Document:

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                                                                     EXHIBIT 4.8

THIS WARRANT AND THE COMMON SHARES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE
NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THIS WARRANT
AND THE COMMON SHARES ISSUABLE UPON EXERCISE OF THIS WARRANT MAY NOT BE SOLD,
OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE
REGISTRATION STATEMENT AS TO THIS WARRANT UNDER SAID ACT OR AN OPINION OF
COUNSEL REASONABLY SATISFACTORY TO JMAR TECHNOLOGIES, INC. THAT SUCH
REGISTRATION IS NOT REQUIRED.

                   Right to Purchase 400,000 Shares of Common Stock of JMAR
                   Technologies, Inc. (subject to adjustment as provided herein)

                          COMMON STOCK PURCHASE WARRANT

No. 2003-1                                            Issue Date: March 21, 2003

         JMAR TECHNOLOGIES, INC., a corporation organized under the laws of the
State of Delaware (the "COMPANY"), hereby certifies that, for value received,
LAURUS MASTER FUND, LTD., or assigns (the "HOLDER"), is entitled, subject to the
terms set forth below, to purchase from the Company from and after the Issue
Date of this Warrant and at any time or from time to time before 5:00 p.m., New
York time, through seven (7) years after such date (the "EXPIRATION DATE"), up
to 400,000 fully paid and nonassessable shares of Common Stock (as hereinafter
defined), no par value, of the Company, at the Exercise Price (as defined
below). The number and character of such shares of Common Stock and the Exercise
Price are subject to adjustment as provided herein.

         As used herein the following terms, unless the context otherwise
requires, have the following respective meanings:

         (a)      The term "Company" shall include JMAR Technologies, Inc. and
any corporation which shall succeed or assume the obligations of JMAR
Technologies, Inc. hereunder.

         (b)      The term "Common Stock" includes (a) the Company's Common
Stock, $.01 par value per share, and (b) any other securities into which or for
which any of the securities described in (a) may be converted or exchanged
pursuant to a plan of recapitalization, reorganization, merger, sale of assets
or otherwise.

         (c)      The term "Other Securities" refers to any stock (other than
Common Stock) and other securities of the Company or any other person (corporate
or otherwise) which the holder of the Warrant at any time shall be entitled to
receive, or shall have received, on the exercise of the Warrant, in lieu of or
in addition to Common Stock, or which at any time shall be issuable or shall
have been issued in exchange for or in replacement of Common Stock or Other
Securities pursuant to Section 4 or otherwise.

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         (d)               The term "EXERCISE PRICE" shall be as follows:

                  (i)      125,000 shares at $1.058 per share;

                  (ii)     75,000 shares at $1.15 per share;

                  (iii)    50,000 shares at $1.33 per share.

         1.       EXERCISE OF WARRANT.

                  1.1      Number of Shares Issuable upon Exercise. From and
after the date hereof through and including the Expiration Date, the Holder
shall be entitled to receive, upon exercise of this Warrant in whole or in part,
by delivery of an original or fax copy of the exercise notice attached hereto as
Exhibit A (the "EXERCISE NOTICE"), shares of Common Stock of the Company,
subject to adjustment pursuant to Section 4. Notwithstanding the foregoing, of
the full 400,000 shares issuable upon exercise of this Warrant, 150,000 shares
of the Common Stock shall only be issuable as follows: for every $20 in
principal of the Note (as defined in Section 9 below) converted into equity, the
Holder will be permitted to exercise this warrant for one share of Common Stock.
By way of example, in the event that the Holder has converted $1,000,000 of the
Note principal into shares of Common Stock, then the Holder will be permitted to
exercise this Warrant with respect to 50,000 of the additional 150,000 shares.
The exercise price for such additional shares shall be 125% of the Fixed
Conversion Price, as defined in the Note, at the time the additional shares
become issuable.

                  1.2      Fair Market Value. Fair Market Value of a share of
Common Stock as of a particular date (the "DETERMINATION DATE") shall mean:

                           (a)      If the Company's Common Stock is traded on
an exchange or is quoted on the National Association of Securities Dealers, Inc.
Automated Quotation ("NASDAQ") National Market or the NASDAQ SmallCap Market,
then the closing or last sale price, respectively, reported for the last
business day immediately preceding the Determination Date.

                           (b)      If the Company's Common Stock is not traded
on an exchange or on the NASDAQ National Market or the NASDAQ SmallCap Market
but is traded on the NASD OTC Bulletin Board or BBX Exchange, then the mean of
the average of the closing bid and asked prices reported for the last business
day immediately preceding the Determination Date.

                           (c)      Except as provided in clause (d) below, if
the Company's Common Stock is not publicly traded, then as the Holder and the
Company agree or in the absence of agreement by arbitration in accordance with
the rules then in effect of the American Arbitration Association, before a
single arbitrator to be chosen from a panel of persons qualified by education
and training to pass on the matter to be decided.

                           (d)      If the Determination Date is the date of a
liquidation, dissolution or winding up, or any event deemed to be a liquidation,
dissolution or winding up pursuant to the Company's charter, then all amounts to
be payable per share to holders of the Common Stock pursuant to the charter in
the event of such liquidation, dissolution or winding up, plus all other amounts
to be payable per share in respect of the Common Stock in liquidation under the
charter,

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assuming for the purposes of this clause (d) that all of the shares of Common
Stock then issuable upon exercise of the Warrant are outstanding at the
Determination Date.

         2.       PROCEDURE FOR EXERCISE.

                  2.1      Delivery of Stock Certificates, etc. on Exercise. The
Company agrees that the shares of Common Stock purchased upon exercise of this
Warrant shall be deemed to be issued to the Holder as the record owner of such
shares as of the close of business on the date on which this Warrant shall have
been surrendered and payment made for such shares as aforesaid. As soon as
practicable after the exercise of this Warrant in full or in part, and in any
event within 3 business days thereafter, the Company at its expense (including
the payment by it of any applicable issue taxes) will cause to be issued in the
name of and delivered to the Holder, or as such Holder (upon payment by such
holder of any applicable transfer taxes) may direct in compliance with
applicable securities laws, a certificate or certificates for the number of duly
and validly issued, fully paid and nonassessable shares of Common Stock (or
Other Securities) to which such Holder shall be entitled on such exercise, plus,
in lieu of any fractional share to which such holder would otherwise be
entitled, cash equal to such fraction multiplied by the then Fair Market Value
of one full share, together with any other stock or other securities and
property (including cash, where applicable) to which such Holder is entitled
upon such exercise pursuant to Section 1 or otherwise.

                  2.2      Exercise.

                           (a)      Payment may be made either in (i) cash or by
certified or official bank check payable to the order of the Company equal to
the applicable aggregate Exercise Price, (ii) by delivery of the Warrant, Common
Stock and/or Common Stock receivable upon exercise of the Warrant in accordance
with Section (b) below, or (iii) by a combination of any of the foregoing
methods, for the number of Common Shares specified in such form (as such
exercise number shall be adjusted to reflect any adjustment in the total number
of shares of Common Stock issuable to the holder per the terms of this Warrant)
and the Holder shall thereupon be entitled to receive the number of duly
authorized, validly issued, fully-paid and non-assessable shares of Common Stock
(or Other Securities) determined as provided herein.

                           (b)      Notwithstanding any provisions herein to the
contrary, if the Fair Market Value of one share of Common Stock is greater than
the Exercise Price (at the date of calculation as set forth below), in lieu of
exercising this Warrant for cash, the Holder may elect to receive shares equal
to the value (as determined below) of this Warrant (or the portion thereof being
exercised) by surrender of this Warrant at the principal office of the Company
together with the properly endorsed Exercise Notice in which event the Company
shall issue to the Holder a number of shares of Common Stock computed using the
following formula:

                  X=Y (A-B)
                      -----
                        A

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         Where X=          the number of shares of Common Stock to be issued to
                           the Holder

               Y=          the number of shares of Common Stock purchasable
                           under the Warrant or, if only a portion of the
                           Warrant is being exercised, the portion of the
                           Warrant being exercised (at the date of such
                           calculation)

               A=          the Fair Market Value of one share of the Company's
                           Common Stock (at the date of such calculation)

               B=          Exercise Price (as adjusted to the date of such
                           calculation)

         3.       EFFECT OF REORGANIZATION, ETC.; ADJUSTMENT OF EXERCISE PRICE.

                  3.1      Reorganization, Consolidation, Merger, etc. In case
at any time or from time to time, the Company shall (a) effect a reorganization,
(b) consolidate with or merge into any other person, or (c) transfer all or
substantially all of its properties or assets to any other person under any plan
or arrangement contemplating the dissolution of the Company, then, in each such
case, as a condition to the consummation of such a transaction, proper and
adequate provision shall be made by the Company whereby the Holder of this
Warrant, on the exercise hereof as provided in Section 1 at any time after the
consummation of such reorganization, consolidation or merger or the effective
date of such dissolution, as the case may be, shall receive, in lieu of the
Common Stock (or Other Securities) issuable on such exercise prior to such
consummation or such effective date, the stock and other securities and property
(including cash) to which such Holder would have been entitled upon such
consummation or in connection with such dissolution, as the case may be, if such
Holder had so exercised this Warrant, immediately prior thereto, all subject to
further adjustment thereafter as provided in Section 4.

                  3.2      Dissolution. In the event of any dissolution of the
Company following the transfer of all or substantially all of its properties or
assets, the Company, prior to such dissolution, shall at its expense deliver or
cause to be delivered the stock and other securities and property (including
cash, where applicable) receivable by the Holder of the Warrant after the
effective date of such dissolution pursuant to Section 3.1 to a bank or trust
company having its principal office in New York, NY, as trustee for the Holder
of the Warrant.

                  3.3      Continuation of Terms. Upon any reorganization,
consolidation, merger or transfer (and any dissolution following any transfer)
referred to in this Section 3, this Warrant shall continue in full force and
effect and the terms hereof shall be applicable to the shares of stock and other
securities and property receivable on the exercise of this Warrant after the
consummation of such reorganization, consolidation or merger or the effective
date of dissolution following any such transfer, as the case may be, and shall
be binding upon the issuer of any such stock or other securities, including, in
the case of any such transfer, the person acquiring all or substantially all of
the properties or assets of the Company, whether or not such person shall have
expressly assumed the terms of this Warrant as provided in Section 4. In the
event this Warrant does not continue in full force and effect after the
consummation of the transactions described in this Section 3, then only in such
event will the Company's securities and property (including cash, where
applicable) receivable by the holders of the Warrant be delivered to the Trustee
as contemplated by Section 3.2.

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                  3.4      Adjustment of Warrant Exercise Price and Number of
Shares upon Issuance of Common Stock. Other than (i) pursuant to warrants,
options or convertible securities that are outstanding as of the date hereof and
warrants, options and convertible securities that may be granted in the future
under any option plan of the Company, or any employment agreement, joint
venture, credit, leasing or other financing agreement or any joint venture or
other strategic arrangement, in each case now or hereinafter entered into by the
Company, (ii) pursuant to any securities issued by the Company to the Holder,
(iii) pursuant to any agreement entered into by the Company or any of its
subsidiaries for the acquisition of another business (whether by stock purchase
or asset purchase, merger or otherwise; ((i), (ii) and (iii) above, are
hereinafter referred to as the "EXCLUDED ISSUANCES")), if the Company at any
time shall issue any shares of Common Stock prior to the complete exercise of
this Warrant for a consideration less than the Purchase Price that would be in
effect at the time of such issue, then, and thereafter successively upon each
such issue, the Purchase Price shall be reduced as follows: (i) the number of
shares of Common Stock outstanding immediately prior to such issue shall be
multiplied by the Purchase Price in effect at the time of such issue and the
product shall be added to the aggregate consideration, if any, received by the
Company upon such issue of additional shares of Common Stock; and (ii) the sum
so obtained shall be divided by the number of shares of Common Stock outstanding
immediately after such issue. The resulting quotient shall be the adjusted
Purchase Price. For purposes of this adjustment, the issuance of any security of
the Company carrying the right to convert such security into shares of Common
Stock or of any warrant, right or option to purchase Common Stock shall result
in an adjustment to the Purchase Price upon the issuance of shares of Common
Stock upon exercise of such conversion or purchase rights..

         4.       EXTRAORDINARY EVENTS REGARDING COMMON STOCK. In the event that
the Company shall (a) issue additional shares of the Common Stock as a dividend
or other distribution on outstanding Common Stock, (b) subdivide its outstanding
shares of Common Stock, or (c) combine its outstanding shares of the Common
Stock into a smaller number of shares of the Common Stock, then, in each such
event, the Exercise Price shall, simultaneously with the happening of such
event, be adjusted by multiplying the then Exercise Price by a fraction, the
numerator of which shall be the number of shares of Common Stock outstanding
immediately prior to such event and the denominator of which shall be the number
of shares of Common Stock outstanding immediately after such event, and the
product so obtained shall thereafter be the Exercise Price then in effect. The
Exercise Price, as so adjusted, shall be readjusted in the same manner upon the
happening of any successive event or events described herein in this Section 4.
The number of shares of Common Stock that the holder of this Warrant shall
thereafter, on the exercise hereof as provided in Section 1, be entitled to
receive shall be increased to a number determined by multiplying the number of
shares of Common Stock that would otherwise (but for the provisions of this
Section 4) be issuable on such exercise by a fraction of which (a) the numerator
is the Exercise Price that would otherwise (but for the provisions of this
Section 4) be in effect, and (b) the denominator is the Exercise Price in effect
on the date of such exercise.

         5.       CERTIFICATE AS TO ADJUSTMENTS. In each case of any adjustment
or readjustment in the shares of Common Stock (or Other Securities) issuable on
the exercise of the Warrant, the Company at its expense will promptly cause its
Chief Financial Officer or other appropriate designee to compute such adjustment
or readjustment in accordance with the terms of the

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Warrant and prepare a certificate setting forth such adjustment or readjustment
and showing in detail the facts upon which such adjustment or readjustment is
based, including a statement of (a) the consideration received or receivable by
the Company for any additional shares of Common Stock (or Other Securities)
issued or sold or deemed to have been issued or sold, (b) the number of shares
of Common Stock (or Other Securities) outstanding or deemed to be outstanding,
and (c) the Exercise Price and the number of shares of Common Stock to be
received upon exercise of this Warrant, in effect immediately prior to such
adjustment or readjustment and as adjusted or readjusted as provided in this
Warrant. The Company will forthwith mail a copy of each such certificate to the
holder of the Warrant and any Warrant agent of the Company (appointed pursuant
to Section 11 hereof).

         6.       RESERVATION OF STOCK, ETC. ISSUABLE ON EXERCISE OF WARRANT.
The Company will at all times reserve and keep available, solely for issuance
and delivery on the exercise of the Warrant, shares of Common Stock (or Other
Securities) from time to time issuable on the exercise of the Warrant.

         7.       ASSIGNMENT; EXCHANGE OF WARRANT. Subject to compliance with
applicable securities laws, this Warrant, and the rights evidenced hereby, may
be transferred by any registered holder hereof (a "TRANSFEROR") with respect to
any or all of the Shares. On the surrender for exchange of this Warrant, with
the Transferor's endorsement in the form of Exhibit B attached hereto (the
"TRANSFEROR ENDORSEMENT FORM") and together with evidence reasonably
satisfactory to the Company demonstrating compliance with applicable securities
laws, which shall include, without limitation, a legal opinion from the
Transferor's counsel that such transfer is exempt from the registration
requirements of applicable securities laws, the Company at its expense but with
payment by the Transferor of any applicable transfer taxes) will issue and
deliver to or on the order of the Transferor thereof a new Warrant of like
tenor, in the name of the Transferor and/or the transferee(s) specified in such
Transferor Endorsement Form (each a "Transferee"), calling in the aggregate on
the face or faces thereof for the number of shares of Common Stock called for on
the face or faces of the Warrant so surrendered by the Transferor.

         8.       REPLACEMENT OF WARRANT. On receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of any such loss, theft or destruction of this
Warrant, on delivery of an indemnity agreement or security reasonably
satisfactory in form and amount to the Company or, in the case of any such
mutilation, on surrender and cancellation of this Warrant, the Company at its
expense will execute and deliver, in lieu thereof, a new Warrant of like tenor.

         9.       REGISTRATION RIGHTS. The Holder of this Warrant has been
granted certain registration rights by the Company. These registration rights
are set forth in a Registration Rights Agreement entered into by the Company and
Purchaser of the Company's Convertible Note (the "NOTE") at or prior to the
issue date of this Warrant.

         10.      MAXIMUM EXERCISE. The Holder shall not be entitled to exercise
this Warrant on an exercise date, in connection with that number of shares of
Common Stock which would result in beneficial ownership by the Holder and its
affiliates of more than 4.99% of the shares of Common Stock of the Company on
such date. For the purposes of the proviso to the

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immediately preceding sentence, beneficial ownership shall be determined in
accordance with Section 13(d) of the Securities Exchange Act of 1934, as
amended, and Regulation 13d-3 thereunder. Subject to the foregoing, the Holder
shall not be limited to aggregate exercises which would result in the issuance
of more than 4.99%. The restriction described in this paragraph may be revoked
upon 75 days prior notice from the Holder to the Company and is automatically
null and void upon an Event of Default under the Note.

         11.      WARRANT AGENT. The Company may, by written notice to the each
holder of the Warrant, appoint an agent for the purpose of issuing Common Stock
(or Other Securities) on the exercise of this Warrant pursuant to Section 1,
exchanging this Warrant pursuant to Section 7, and replacing this Warrant
pursuant to Section 8, or any of the foregoing, and thereafter any such
issuance, exchange or replacement, as the case may be, shall be made at such
office by such agent.

         12.      TRANSFER ON THE COMPANY'S BOOKS. Until this Warrant is
transferred on the books of the Company, the Company may treat the registered
holder hereof as the absolute owner hereof for all purposes, notwithstanding any
notice to the contrary.

         13.      NOTICES, ETC. All notices and other communications from the
Company to the Holder of this Warrant shall be mailed by first class registered
or certified mail, postage prepaid, at such address as may have been furnished
to the Company in writing by such holder or, until any such Holder furnishes to
the Company an address, then to, and at the address of, the last Holder of this
Warrant who has so furnished an address to the Company.

         14.      VOLUNTARY ADJUSTMENT BY THE COMPANY. The Company may at any
time during the term of this Warrant reduce the then current Exercise Price to
any amount and for any period of time deemed appropriate by the Board of
Directors of the Company.

         15.      MISCELLANEOUS. This Warrant and any term hereof may be
changed, waived, discharged or terminated only by an instrument in writing
signed by the party against which enforcement of such change, waiver, discharge
or termination is sought. This Warrant shall be governed by and construed in
accordance with the laws of State of New York without regard to principles of
conflicts of laws. Any action brought concerning the transactions contemplated
by this Warrant shall be brought only in the state courts of New York or in the
federal courts located in the state of New York; provided, however, that the
Holder may choose to waive this provision and bring an action outside the state
of New York. The individuals executing this Warrant on behalf of the Company
agree to submit to the jurisdiction of such courts and waive trial by jury. The
prevailing party shall be entitled to recover from the other party its
reasonable attorney's fees and costs. In the event that any provision of this
Warrant is invalid or unenforceable under any applicable statute or rule of law,
then such provision shall be deemed inoperative to the extent that it may
conflict therewith and shall be deemed modified to conform with such statute or
rule of law. Any such provision which may prove invalid or unenforceable under
any law shall not affect the validity or enforceability of any other provision
of this Warrant. The headings in this Warrant are for purposes of reference
only, and shall not limit or otherwise affect any of the terms hereof. The
invalidity or unenforceability of any provision hereof shall in no way affect
the validity or enforceability of any other provision. The Company acknowledges
that legal counsel participated in the preparation of this Warrant and,
therefore, stipulates that the rule

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of construction that ambiguities are to be resolved against the drafting party
shall not be applied in the interpretation of this Warrant to favor any party
against the other party.

                      [THIS SPACE INTENTIONALLY LEFT BLANK]

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         IN WITNESS WHEREOF, the Company has executed this Warrant under seal as
of the date first written above.

                                             JMAR TECHNOLOGIES, INC.

                                             By:      /s/ Joseph G. Martinez
                                                --------------------------------
                                                      Joseph G. Martinez
                                                      Senior Vice President

Witness:

______________________________

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                                                                       EXHIBIT A

                              FORM OF SUBSCRIPTION
                   (To be signed only on exercise of Warrant)

TO:      JMAR Technologies, Inc.

The undersigned, pursuant to the provisions set forth in the attached Warrant
(No.____), hereby irrevocably elects to purchase (check applicable box):

___    ________ shares of the Common Stock covered by such Warrant; or

___    the maximum number of shares of Common Stock covered by such Warrant
pursuant to the cashless exercise procedure set forth in Section 2.

The undersigned herewith makes payment of the full Exercise Price for such
shares at the price per share provided for in such Warrant, which is
$___________. Such payment takes the form of (check applicable box or boxes):

___    $__________ in lawful money of the United States; and/or

___    the cancellation of such portion of the attached Warrant as is
exercisable for a total of _______ shares of Common Stock (using a Fair Market
Value of $_______ per share for purposes of this calculation); and/or

___    the cancellation of such number of shares of Common Stock as is
necessary, in accordance with the formula set forth in Section 2, to exercise
this Warrant with respect to the maximum number of shares of Common Stock
purchaseable pursuant to the cashless exercise procedure set forth in Section 2.

The undersigned requests that the certificates for such shares be issued in the
name of, and delivered to _______________ whose address is______________________

_____________________________________.

The undersigned represents and warrants that all offers and sales by the
undersigned of the securities issuable upon exercise of the within Warrant shall
be made pursuant to registration of the Common Stock under the Securities Act of
1933, as amended (the "Securities Act") or pursuant to an exemption from
registration under the Securities Act.

Dated:___________________           ____________________________________________
                                    (Signature must conform to name of holder as
                                    specified on the face of the Warrant)

                                    ____________________________________________
                                    (Address)

<PAGE>

                                                                       EXHIBIT B

                         FORM OF TRANSFEROR ENDORSEMENT
                   (To be signed only on transfer of Warrant)

                  For value received, the undersigned hereby sells, assigns, and
transfers unto the person(s) named below under the heading "Transferees" the
right represented by the within Warrant to purchase the percentage and number of
shares of Common Stock of JMAR Technologies, Inc. to which the within Warrant
relates specified under the headings "Percentage Transferred" and "Number
Transferred," respectively, opposite the name(s) of such person(s) and appoints
each such person Attorney to transfer its respective right on the books of JMAR
Technologies, Inc. with full power of substitution in the premises.

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
                                 Percentage                     Number
    Transferees                  Transferred                 Transferred
--------------------------------------------------------------------------------
<S>                              <C>                         <C>

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
</TABLE>

Dated:___________________           ____________________________________________
                                    (Signature must conform to name of holder as
                                    specified on the face of the Warrant)

Signed in the presence of:

_________________________________         ______________________________________
             (Name)                                      (address)

ACCEPTED AND AGREED:                      ______________________________________
[TRANSFEREE]                                             (address)

________________________________
             (Name)<PAGE>

                                                                   EXHIBIT 4.9

         THIS NOTE AND THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF
         THIS NOTE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
         AMENDED. THIS NOTE AND THE SHARES OF COMMON STOCK ISSUABLE UPON
         CONVERSION OF THIS NOTE MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR
         HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT AS
         TO THIS NOTE OR THE SHARES OF COMMON STOCK UNDER SAID ACT OR AN OPINION
         OF COUNSEL REASONABLY SATISFACTORY TO JMAR TECHNOLOGIES, INC., THAT
         SUCH REGISTRATION IS NOT REQUIRED.

                                CONVERTIBLE NOTE

                  FOR VALUE RECEIVED, JMAR TECHNOLOGIES, INC., a Delaware
Borrower ("JMAR"), JMAR RESEARCH, INC., a California Borrower ("JRI"), JMAR/SAL
NANOLITHOGRAPHY, INC. a California Borrower ("JSAL"), JSI MICROELECTRONICS,
INC., a California Borrower ("JME" and together with JRI, JSAL and JMAR, the
"BORROWER"), jointly and severally, hereby promise to pay to LAURUS MASTER FUND,
LTD., c/o Ironshore Corporate Services Ltd., P.O. Box 1234 G.T., Queensgate
House, South Church Street, Grand Cayman, Cayman Islands, Fax: 345-949-9877 (the
"HOLDER") or its registered assigns or successors in interest, on order, without
demand, the outstanding principal amount of all loans made by the Holder to the
Borrower under the terms of this Note (each an "ADVANCE" and collectively the
"ADVANCES"). The aggregate principal amount of all Advances outstanding
hereunder shall not exceed THREE MILLION DOLLARS ($3,000,000), and no Advance
shall be made after March 21, 2006 (the "MATURITY DATE"). The amount and date of
each Advance shall be entered by the Holder into Holder's records, which records
shall be conclusive evidence of the subject matter thereof absent manifest
error.

                  Capitalized terms used herein without definition shall have
the meanings ascribed to such terms in the Purchase and Security Agreement
between the Borrower and the Holder dated the date hereof (the "PURCHASE
AGREEMENT").

                  The following terms shall apply to this Note:

                                   ARTICLE I

                                    INTEREST

                  1.1      Interest Rate. Except as modified by Section 1.2
below, the Borrower shall pay interest at the Contract Rate on the unpaid
principal balance of the Note until such time as such balance or portion thereof
is collected in full in good funds in dollars of the United States of America.
Interest shall be payable in arrears commencing one month from the date hereof
and on the first business day of each consecutive calendar month thereafter, and
on the Maturity Date, accelerated or otherwise, due and payable as described
below.

                  1.2      Default Rate. After the Default Notice Period, the
Default Rate, as defined in the Purchase Agreement, shall apply to the amounts
owed hereunder.

<PAGE>

                                   ARTICLE II

                              ADVANCES UNDER NOTE

                  2.1      Authorized Person.

                  (a)      Any officer of JMAR who has been disclosed to the
Holder in writing as an authorized officer for such purposes (an "AUTHORIZED
PERSON") may request an Advance on any day other than a Saturday, Sunday or
other day when commercial banks located in New York, New York are not open for
commercial banking business. Such request shall be made in writing delivered to
the Holder by not later than 12:00 p.m. on the day of the requested Advance.

                  (b)      The Borrower hereby authorizes the Holder to rely
upon the written instructions of any person identifying himself or herself as an
Authorized Person and upon any signature which the Holder believes to be
genuine, and the Borrower shall be bound thereby in the same manner as if such
person were authorized or such signature were genuine.

         2.2      Limitation on Advances. It is expressly understood that the
Holder is under no obligation to make any Advance to the Borrower under this
Note (whether by reason of any provision hereof or otherwise) (i) if an Event of
Default, as hereinafter defined, has occurred and is continuing, or (ii) if such
Advance or any part thereof would cause the aggregate amount of all Advances
made hereunder to exceed the Accounts Availability.

                                   ARTICLE III

                                CONVERSION RIGHTS

                  3.1.     Conversion into JMAR's Common Stock.

                  (a)      To the extent that Advances have been made hereunder,
the Holder shall have the right, but not the obligation (except as provided in
Section 3.3 hereof), from and after the date hereof, and then, subject to
Section 3.1(c) at any time until the Maturity Date, to convert the principal
portion of the Advances made hereunder and/or interest and fees due and payable
into fully paid and nonassessable shares of common stock of JMAR as such stock
exists on the date of issuance of this Note, or any shares of capital stock of
JMAR into which such stock shall hereafter be changed or reclassified (the
"COMMON STOCK") at the Conversion Price as defined below. In the event that the
Holder elects to convert this Note into Common Stock (to the extent permitted
herein), the Holder shall give notice of such election by delivering an executed
and completed notice of conversion ("NOTICE OF CONVERSION") to JMAR and such
Notice of Conversion shall provide a breakdown in reasonable detail of the
amount of Note principal, interest and fees that are being converted. On each
Conversion Date (as hereinafter defined) and in accordance with its Notice of
Conversion, the Holder shall make the appropriate reduction to the Advances,
interest and fees as entered in its records and shall provide written notice
thereof to the Borrower within 2 business days after the Conversion Date. Each
date on

                                        2

<PAGE>

which a Notice of Conversion is delivered or telecopied to JMAR in accordance
with the provisions hereof shall be deemed a Conversion Date (the "CONVERSION
DATE"). A form of Notice of Conversion that may be employed by the Holder is
annexed hereto as Exhibit A. JMAR will cause the transfer agent to transmit the
certificates representing the shares of the Common Stock issuable upon
conversion of the Note to the Holder by crediting the account of the Holder's
designated broker with the Depository Trust Borrower ("DTC") through its Deposit
Withdrawal Agent Commission ("DWAC") system within three (3) business days after
receipt by JMAR of the Notice of Conversion (the "DELIVERY DATE").

                  In the case of the exercise of the conversion rights set forth
herein the conversion privilege shall be deemed to have been exercised and the
shares of Common Stock issuable upon such conversion shall be deemed to have
been issued upon the date of receipt by JMAR of the Notice of Conversion. The
Holder shall be treated for all purposes as the record holder of such Common
Stock, unless the Holder provides JMAR written instructions to the contrary.

                  (b)      The Conversion Price per share shall be $0.92 (the
"CONVERSION PRICE"); provided, however that if the Conversion Price as adjusted
by this proviso is greater than the Conversion Price prior to such adjustment,
then for every $2 million of conversions made hereunder, the Conversion Price
thereafter shall be increased to equal 103% of the average closing price for the
three days prior to the last day of the period during which such $2 million has
been converted. The Conversion Price is subject to further adjustment as
provided in Section 3.1(e) hereof.

                  If after the Default Notice Period (as defined below) the
Borrower has not repaid in full the amounts then due hereunder or cured the
Event of Default, then the Conversion Price shall be reduced and shall be equal
to the lower of (i) the Conversion Price; or (ii) eighty percent (80%) of the
average of the three lowest closing prices for the Common Stock on NASD OTC
Bulletin Board, NASDAQ SmallCap Market, NASDAQ National Market System, American
Stock Exchange, or New York Stock Exchange (whichever of the foregoing is at the
time the principal trading exchange or market for the Common Stock, the
"PRINCIPAL MARKET"), or on any securities exchange or other securities market on
which the Common Stock is then being listed or traded, for the thirty (30)
trading days prior to but not including the Conversion Date.

                  (c)      Notwithstanding anything contained herein to the
contrary, the Holder shall not be entitled to convert pursuant to the terms of
this Note an amount that wouldresult in the Holder's beneficial ownership (as
defined below) of JMAR Common Stock being in excess of 4.99%. For the purposes
of the immediately preceding sentence, beneficial ownership shall be determined
in accordance with Section 13(d) of the Exchange Act and Regulation 13d-3
thereunder. The Holder may void the conversion limitation described in this
section upon 75 days prior notice to JMAR or upon an Event of Default hereunder.

                  (d)      The Borrower understands that a delay in the delivery
of the shares of Common Stock in the form required pursuant to this Article
beyond the Delivery Date could result in economic loss to the Holder. As
compensation to the Holder for such loss, the Borrower agrees to pay late
payments to the Holder for late issuance of the such shares in the form required
pursuant to this Article III upon conversion of the Note, in the amount equal to
the greater of (i) $500 per business day after the Delivery Date and (ii) the
Holder's actual damages from such delayed delivery. The Borrower shall pay any
payments incurred under this Section in immediately available funds upon demand
and, in the case of actual damages, accompanied by reasonable documentation of
the amount of such damages. Such documentation shall show the number of shares
of Common Stock the Purchaser is forced to purchase (in an open market
transaction) which the Purchaser anticipated receiving upon such conversion, and
shall be calculated as the amount by which (A) the

                                        3

<PAGE>

Purchaser's total purchase price (including customary brokerage commissions, if
any) for the shares of Common Stock so purchased exceeds (B) the aggregate
principal and/or interest amount of the Note, for which such Conversion Notice
was not timely honored.

                  (e)      The Conversion Price and number and kind of shares or
other securities to be issued upon conversion shall be subject to adjustment
from time to time upon the happening of certain events while this conversion
right remains outstanding, as follows):

                           A.       Merger, Sale of Assets, etc. The Borrower at
any time shall consolidate with or merge into or sell or convey all or
substantially all its assets to any other Borrower, this Note, as to the unpaid
principal portion thereof and accrued interest thereon shall thereafter be
deemed to evidence the right to purchase such number and kind of shares or other
securities and property as would have been issuable or distributable on account
of such consolidation, merger, sale or conveyance, upon or with respect to the
number of shares of Common Stock the Holder could have acquired immediately
prior to such consolidation, merger, sale or conveyance based on the Conversion
Price as of the closing date thereof. The foregoing provision shall similarly
apply to successive transactions of a similar nature by any such successor or
purchaser. Without limiting the generality of the foregoing, the provisions of
this Section shall apply to such securities of such successor or purchaser after
any such consolidation, merger, sale or conveyance.

                           B.       Reclassification, etc. If the Borrower at
any time shall, by reclassification or otherwise, change the Common Stock into
the same or a different number of securities of any class or classes, this Note,
as to the unpaid principal portion thereof and accrued interest thereon, shall
thereafter be deemed to evidence the right to purchase an adjusted number of
such securities and kind of securities as would have been issuable as the result
of such change with respect to the number of shares of Common Stock into which
the Note would have been convertible immediately prior to such reclassification
or other change at the Conversion Price as of the effective date for such
reclassification or change.

                           C.       Stock Splits, Combinations and Dividends. If
the shares of Common Stock are subdivided or combined into a greater or smaller
number of shares of Common Stock, or if a dividend is paid on the Common Stock
in shares of Common Stock, the Conversion Price shall be proportionately reduced
in case of subdivision of shares or stock dividend or proportionately increased
in the case of combination of shares, in each such case by the ratio which the
total number of shares of Common Stock outstanding immediately after such event
bears to the total number of shares of Common Stock outstanding immediately
prior to such event.

                           D.       Share Issuance. Subject to the provisions of
this Section, if the Borrower at any time shall issue any shares of Common Stock
prior to the conversion of the portion of the principal amount of the Note
permitted by Section 3.1(a) (otherwise than as: (i) provided in Sections
3.1(e)A, 3.1(e)B or 3.1(e)C or this subparagraph D; (ii) pursuant to warrants,
options or convertible securities that are outstanding as of the Closing Date
and warrants, options and convertible securities that may be granted in the
future under any option plan of the Borrower, or any employment agreement, joint
venture, credit, leasing or other financing agreement or any joint venture or
other strategic arrangement, in each case now or hereinafter entered into by the
Borrower, (iii) pursuant to any securities issued by the Borrower to the Holder;
or (iv) pursuant to any agreement entered into by the Company or any of its
subsidiaries for the acquisition of another business (whether by stock purchase
or asset purchase, merger or otherwise; ((i), (ii) and (iii) above, are
hereinafter referred to as the "EXCLUDED ISSUANCES")) for a consideration less
than the Conversion Price that would be in effect at the time of such issue,
then, and thereafter successively upon each such issue, the Conversion Price

                                        4

<PAGE>

shall be reduced as follows: (i) the number of shares of Common Stock
outstanding immediately prior to such issue shall be multiplied by the
Conversion Price in effect at the time of such issue and the product shall be
added to the aggregate consideration, if any, received by the Borrower upon such
issue of additional shares of Common Stock; and (ii) the sum so obtained shall
be divided by the number of shares of Common Stock outstanding immediately after
such issue. The resulting quotient shall be the adjusted Conversion Price.
Except for the Excluded Issuances for purposes of this adjustment, the issuance
of any security of the Borrower carrying the right to convert such security into
shares of Common Stock or of any warrant, right or option to purchase Common
Stock shall result in an adjustment to the Conversion Price upon the issuance of
shares of Common Stock upon exercise of such conversion or purchase rights.

                  (f)      During the period the conversion right exists, JMAR
will reserve from its authorized and unissued Common Stock a sufficient number
of shares to provide for the issuance of Common Stock upon the conversion of
this Note to the extent permitted by Section 3.1(a). JMAR represents that upon
issuance, such shares will be duly and validly issued, fully paid and
non-assessable. JMAR agrees that JMAR's issuance of this Note shall constitute
full authority to JMAR's officers, agents, and transfer agents who are charged
with the duty of executing and issuing stock certificates to execute and issue
the necessary certificates for shares of Common Stock upon the conversion of
this Note.

                  3.2      Registration Rights. The Holder has been granted
registration rights with respect to the shares of Common Stock issuable upon
conversion of this Note as more fully set forth in a Registration Rights
Agreement dated the date hereof (the "REGISTRATION RIGHTS AGREEMENT.")

                  3.3      Required Conversion. In the event that the volume
weighted average price (as determined by the AQR function on the Bloomberg
terminal) of JMAR's Common Stock for all trades during any 11 consecutive
trading day period on the Principal Market is greater than 118% of the
Conversion Price, then JMAR may, at its sole option, provide the Holder
irrevocable written notice ("CALL NOTICE") requiring the conversion at the
Conversion Price of all or a portion of the Note held by the Holder as of the
date set forth in such Call Notice (the "CALL DATE"), which such date shall be
at least 11 trading days following the date of the Call Notice, provided a
registration statement covering resales of that number of shares of Common Stock
then issuable upon conversion of this Note pursuant to such Call Notice has been
declared effective and is available for use. The amount of Common Stock to be
issued in connection with any such conversion pursuant to a particular Call
Notice pursuant to this Section 3.3 shall not exceed 25% of the aggregate dollar
trading volume of the Common Stock for the 11 trading days immediately preceding
the Call Date. If the volume weighted average price (as determined by the AQR
function on the Bloomberg terminal) of the Common Stock for all trades during
any 11 consecutive trading day period preceding the Call Date falls below 118%
of the Conversion Price during the 11 trading day period preceding the Call
Date, then the Holder will no longer be required to convert the Note pursuant to
such Call Notice. JMAR shall not be permitted to give the Investor more than one
notice during any 22-day period.

                  3.4      Overall Limit on Common Stock Issuable. For so long
as the Borrower is subject to the rules of the Nasdaq Stock Market, the number
of shares of Common Stock issuable by the Borrower and acquirable by the Holder
under all securities issued by the Company to the Holder, shall not exceed
4,769,535 shares, subject to appropriate adjustment for stock splits, stock
dividends, or other similar recapitalizations

                                        5

<PAGE>

affecting the Common Stock (the "MAXIMUM COMMON STOCK ISSUANCE"), unless the
issuance of shares hereunder in excess of the Maximum Common Stock Issuance
shall first be approved by the Borrower's shareholders. If at any point in time
and from time to time the number of shares of Common Stock issued pursuant to
conversion of this Note, together with the number of shares of Common Stock that
would then be issuable by the Borrower in the event of the conversion or
exercise of all other securities issued by the Company, would exceed the Maximum
Common Stock Issuance but for this Section, then upon written notice provided by
the Holder, which such notice shall not be provided until the Holder has been
issued in the aggregate not less than 3,500,000 shares of Common Stock, the
Borrower shall promptly call a shareholders meeting to obtain shareholder
approval for the issuance of the shares of Common Stock hereunder in excess of
the Maximum Common Stock Issuance.

                                   ARTICLE IV

                                EVENT OF DEFAULT

                  If an Event of Default (as defined below) occurs and is
continuing, the Holder may make all sums of principal, accrued but unpaid
interests and other fees then remaining unpaid hereon and all other amounts
payable hereunder due and payable within 5 days of written notice from the
Holder to the Borrower (each occurrence being a "DEFAULT NOTICE PERIOD") of an
Event of Default. If during the Default Notice Period, the Borrower cures the
Event of Default, the Event of Default will no longer exist and any rights the
Holder had pertaining to the Event of Default will no longer exist. If after the
Default Notice Period, the Event of Default has not been cured, all amounts
payable hereunder shall be immediately due and payable, all without further
demand, presentment or notice, or grace period, all of which hereby are
expressly waived. In the event of such an acceleration, the amount due and owing
to the Holder shall be 120% of the outstanding principal amount of the Note
(plus accrued and unpaid interest and fees, if any). The remedies under this
Note shall be cumulative.

                  The occurrence of any of the following events is an Event of
Default ("EVENT OF DEFAULT"):

                  4.1      Failure to Deliver Common Stock or Replacement Note.
The Borrower's failure to timely deliver Common Stock to the Holder pursuant to
and in the form required by this Note.

                  4.2      Stop Trade. An SEC stop trade order or Principal
Market trading suspension of the Common Stock for 5 consecutive days or 5 days
during a period of 10 consecutive days, excluding in all cases a suspension of
all trading on a Principal Market.

                  4.3      Default Under Related Agreement. An Event of Default
occurs under and as defined in the Purchase Agreement dated as of the date
hereof between Borrower and Holder, as such agreement may be amended, modified
and supplemented from time to time.

                                        6

<PAGE>

                                    ARTICLE V

                                  MISCELLANEOUS

                  5.1      Failure or Indulgence Not Waiver. No failure or delay
on the part of the Holder hereof in the exercise of any power, right or
privilege hereunder shall operate as a waiver thereof, nor shall any single or
partial exercise of any such power, right or privilege preclude other or further
exercise thereof or of any other right, power or privilege. All rights and
remedies existing hereunder are cumulative to, and not exclusive of, any rights
or remedies otherwise available.

                  5.2      Notices. Any notice herein required or permitted to
be given shall be in writing and shall be deemed effectively given: (a) upon
personal delivery to the party notified, (b) when sent by confirmed telex or
facsimile if sent during normal business hours of the recipient, if not, then on
the next business day, (c) five days after having been sent by registered or
certified mail, return receipt requested, postage prepaid, or (d) one day after
deposit with a nationally recognized overnight courier, specifying next day
delivery, with written verification of receipt. All communications shall be sent
to (i) the Borrower at the address as set forth on the signature page to the
Purchase Agreement executed in connection herewith and, as the case may be, to
the Borrower at the address as set forth in Section 6(g) of the Registration
Rights Agreement, in each case, and (ii) the Holder at the address set forth on
the signature page to the Purchase Agreement for such Holder, with a copy to
Daniel M. Laifer, Esq., 152 West 57th Street, 4th Floor, New York, New York
10019, facsimile number (212) 541-4434, or at such other address as the
Borrower, the Borrower or the Holder may designate by ten days advance written
notice to the other parties hereto made and delivered in accordance with this
Section 5.2.

                  5.3      Amendment Provision. The term "Note" and all
reference thereto, as used throughout this instrument, shall mean this
instrument as originally executed, or if later amended or supplemented, then as
so amended or supplemented.

                  5.4      Assignability. This Note (except for Article III)
shall be binding upon the Borrower and its successors and assigns, and shall
inure to the benefit of the Holder and its successors and assigns, and may be
assigned by the Holder. Article III and Article V of this Note (excluding
Section 5.6 and 5.7) shall be binding upon the Borrower and its successors and
assigns.

                  5.5      Governing Law. This Note shall be governed by and
construed in accordance with the laws of the State of New York, without regard
to principles of conflicts of laws. Any action brought by either party against
the other concerning the transactions contemplated by this Agreement shall be
brought only in the state courts of New York or in the federal courts located in
the state of New York; provided, however that the Purchaser may choose to waive
this provision and bring an action outside the state of New York. Both parties
and the individual signing this Note on behalf of the Borrower, the Borrower and
the Holder agree to submit to the jurisdiction of such courts. The prevailing
party shall be entitled to recover from the other party its reasonable
attorney's fees and costs. In the event that any provision of this Note is
invalid or unenforceable under any applicable statute or rule of law, then such
provision shall be deemed inoperative to the extent that it

                                        7

<PAGE>

may conflict therewith and shall be deemed modified to conform with such statute
or rule of law. Any such provision which may prove invalid or unenforceable
under any law shall not affect the validity or unenforceability of any other
provision of this Note.

                  5.6      Maximum Payments. Nothing contained herein shall be
deemed to establish or require the payment of a rate of interest or other
charges in excess of the maximum permitted by applicable law. In the event that
the rate of interest required to be paid or other charges hereunder exceed the
maximum permitted by such law, any payments in excess of such maximum shall be
credited against amounts owed by the Borrower to the Holder and thus refunded to
the Borrower.

                  5.7      Security Interest. The holder of this Note has been
granted a security interest in certain assets of the Borrower more fully
described in the Purchase Agreement.

                  5.8      Construction. Each party acknowledges that its legal
counsel participated in the preparation of this Note and, therefore, stipulates
that the rule of construction that ambiguities are to be resolved against the
drafting party shall not be applied in the interpretation of this Note to favor
any party against the other.

                                        8

<PAGE>

        IN WITNESS WHEREOF, the Borrower has caused this Note to be signed in
its name effective as of this 21st day of March, 2003.

                                             JMAR TECHNOLOGIES, INC.

                                             By:    /s/ Ronald A. Walrod
                                                --------------------------------
                                             Name:  Ronald A. Walrod
                                             Title: Chief Executive Officer

                                             JMAR RESEARCH, INC.

                                             By:    /s/ Ronald A. Walrod
                                                --------------------------------
                                             Name:  Ronald A. Walrod
                                             Title: Acting President

                                             JMAR/SAL NANOLITHOGRAPHY, INC.

                                             By:    /s/ Dennis E. Valentine
                                                --------------------------------
                                             Name:  Dennis E. Valentine
                                             Title: Chief Financial Officer

                                             JSI MICROELECTRONICS, INC.

                                             By:    /s/ Dennis E. Valentine
                                                --------------------------------
                                             Name:  Dennis E. Valentine
                                             Title: Chief Financial Officer

                                        9

<PAGE>

                              NOTICE OF CONVERSION

(To be executed by the Holder in order to convert the Note)

         The undersigned hereby elects to convert $_________ of the principal
and $_________ of the interest due on the Note issued by JMAR TECHNOLOGIES, INC.
on March 21, 2003 into Shares of Common Stock of JMAR TECHNOLOGIES, INC. (the
"Company") according to the conditions set forth in such Note, as of the date
written below.

Date of Conversion:_____________________________________________________________

Conversion Price:_______________________________________________________________

Shares To Be Delivered:_________________________________________________________

DTC Number:_____________________________________________________________________

Account Number:_________________________________________________________________

Signature:______________________________________________________________________

Print Name:_____________________________________________________________________

Address:________________________________________________________________________

        ________________________________________________________________________

                                       10

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