MIXED GAS ION LASER

Abstract: A laser (10) that is capable of producing light from a chosen group of frequencies not available using a single gas laser is provided. The laser (10) is capable of producing selected and well defined light wavelengths. The laser (10) is also capable of eliminating unwanted frequencies in order to prevent such frequencies from robbing power from the desired wavelengths. The laser (10) constitutes a multiple gas laser. A combination of argon and krypton is used. Argon is known to produce a good blue laser beam in the area of 488 nm. Mixed with the argon is krypton. Krypton also produces a blue output at 482 nm and 476 nm. In addition, krypton produces strong outputs in red, yellow and green wavelengths (647 nm, 568 nm, and 529 nm respectively). Accordingly, access to each of these colors is provided by the argon-krypton in the mixture. Certain light frequencies are unnecessary and undesirable. Elimination of undesirable wavelengths is accomplished primarily through the optics used. Optics (18, 20) are chosen which transmit unwanted wavelengths. As a result no lasing action takes place at the unwanted wavelengths.

Description: MIXED GAS ION LASER BACKGROUND 1. Field of the Invention The present invention is related to an ion laser which is capable of producing light from a chosen group of frequencies, said group of frequencies not being available using lasers employing a single gas. More particularly, the present invention is related to a compact, continuous output, ion laser which employs a combination of gases, such as argon and krypton gases, such that a controlled laser output of multiple wavelengths can be produced by a single laser. 2. Background of the Invention Lasers are used extensively in industry, science, and entertainment. It will be appreciated that lasers are found to be particularly useful because of their ability to produce a coherent beam of intense light. For many applications it is desirable to produce light having a certain dependable and reproducible wavelength. One type of laser that has achieved widespread acceptance is the ion laser. Among other factors, the ion laser is often preferred because of its potential to be compact in size and inexpensive to manufacture. In essence, the ion laser operates by exciting a gas contained within a tube in order to produce an emission of photons of a particular discrete wavelength. In the typical ion laser, atoms are excited by electrical discharge to an excited ion state. The excited atoms, being inherently unstable, have a tendency to return to a lower energy state. Accordingly, photons of specific frequencies are emitted by the electrically excited atoms in order for those atoms to return to a stable energy state. During this process both heat and light energy are produced. The basic ion laser consists of three primary components. These include a resonator, a laser tube (plasma tube) , and a power supply. The resonator generally holds two reflective surfaces, such as mirrors, in alignment. The mirrors then define the "optical cavity" or the area in which the laser beam is generated. In the typical ion laser, one of the mirrors is totally reflective of light in the desired wavelengths. This mirror is often referred to as a high reflector. The other mirror (output coupler) , is partially transmissive of the subject frequency in order to allow a fraction of the light energy stored in the optical cavity to escape. The escaping energy constitutes the output beam. The laser tube provides optical gain within the resonator, causing it to act as an oscillator of the desired light frequency. In the case of the ion laser, the power supply provides DC voltage and an adjustable current across the plasma tube to sustain a controlled arc discharge through the gas of the laser tube. Direct current also provides for a continuous laser discharge, unlike excimer lasers and other such devices which produce a pulsed output. In the discharge, the ionized atoms of the gas are excited through multiple collisions with accelerated electrons. As mentioned above, ion lasers often use noble gases such as krypton and argon in the laser tube. Thus, stimulated emission from the various excited states to the ground state of the ionized argon or krypton atom produces the required lasing action. Depending on physical conditions of the discharge, a fraction of the noble gas atoms may be double ionized. Stimulated emission from these states occur as well giving rise to multiple frequency discharges. During operation of an ion laser, the photons emitted during an induced transition of the type mentioned above, have the same phase and direction as the inducing electron wave (i.e. , they are coherent with the wave that induces the transition) . A single atom may radiate a photon in any direction. However, many atoms distributed over a finite volume (within the laser tube) , and radiating coherently, cooperate to generate a wave having the same propagation vector as the inducing wave, within the limits of a diffraction pattern. That is, they amplify the inducing wave. Thus, the radiation from induced emission has a spectral distribution identical to that of the inducing radiation. It is found that certain types of atoms produce certain specific wavelengths of radiation during the energy transition and emission of photons. For example, argon, a common substance for use in an ion lasing medium, produces approximately primary nine distinct wavelengths of radiation. The most commonly used wavelengths for laser purposes are at approximately 488 nm and 514 nm. Krypton, another gas used in ion lasers, also produces distinct wavelengths of radiation, including radiation at approximately 647 nm, 568 n , 530 nm, and 520 nm. It will be appreciated that once a distinct wavelength of radiation is isolated, it can be used to produce a lasing action as it oscillates through the optical cavity. For some applications, it is desirable to have more than a single output frequency and it is particularly useful to have output from the laser in both the blue wavelengths, and at least one other usable wavelength. For example, the combinations of blue and yellow and blue and red are found to be particularly useful. One context in which multiple wavelength laser outputs are desired is in the area of scientific research. For example, it has been found that laser produced light is capable of causing certain microscopic structures to fluoresce after being stained with a selected dye. Certain structures fluoresce under blue laser radiation, while other structures fluoresce under red or yellow radiation. Thus, it would often be useful to have the capacity to direct laser produced light of multiple wavelengths onto a particular microscopic sample of interest. Thus, distinct structures could be simultaneously viewed, studied, and compared without the need to switch lasers or to focus multiple lasers. Until now, however, it has been impractical to employ conventional lasers in this context. In order to make this type of use practical it is necessary to provide a laser which produces a constant output and which is sufficiently portable to attach to a microscope or similar apparatus. Known multiple output lasers, are very generally large, expensive and water cooled. Thus, it is impractical to use that type of laser in the context of a microscope. Other problems, such as difficulty in adjustment and the production of different colored output beams of widely varying power also limit the usefulness of existing lasers. Employing known technology it is difficult to select output power, particularly where more than one frequency is involved. Laser beams of specific colors have also been found useful in the printing industry. In the area of color separation it is often desirable to have the capability of irradiating a piece of work with both red and blue light. Other colors may also be useful in certain situations. This reduces the number of steps and the complexity of the color separation process. Again, however, the limitations of existing lasers make the use of lasers in printing less than totally desirable, particularly since it is often necessary to use multiple lasers. In the study of flow dynamics, lasers of particular wavelengths may have great usefulness. One technique which has employed lasers is "Laser Doppler Velocimetry." Using multiple colored laser light, it would be possible to obtain extensive data concerning flow dynamics and to track multiple variables. Such techniques would be useful, for example, in the production and design of aircraft. Thus, it will be appreciated that portable, constant output, ion lasers which could also produce multiple colored outputs would be very useful. In order to achieve a multiple colored laser beams of specific wavelengths, it is conventional in the art to employ multiple lasers. It has been found useful to provide an argon laser and a helium-neon laser together such that the blue produced by the argon laser and the red produced by the helium- neon laser will both be available. Problems with this approach are obvious and have been mentioned briefly above. It is necessary to align two separate and distinct lasers. Alignment of the lasers is critical to the applications discussed above. Yet, in using multiple lasers to produce each individual desired color, it is virtually impossible to produce a coaxial output beam. Thus, alignment problems continue to plague the user. Prior attempts to produce a multiple color output laser have been less than satisfactory in that specific, selected wavelengths have not been available. Rather, many such lasers produce a broad band of wavelengths which may be only marginally useful. At the same time it was not possible to precisely control the output power of the desired frequencies. Thus, production of a usable multiple frequency output beam has been difficult. Another problem is the production of undesirable colors. As mentioned above, conventional multiple color lasers produce a wide spectrum of output frequencies, including frequencies which may degrade desired output. In the case of an argon laser, light of at least nine separate and distinct wavelengths is produced. Many of these wavelengths may not be needed or wanted for a particular application. Accordingly, these wavelengths will reduce the power output of the laser for the desirable wavelengths. This problem is multiplied when multiple lasers are combined. Accordingly, it would be an advancement in the art to provide a mechanism for producing multiple colors of laser light while avoiding the problems encountered in the art. More particularly, it would be an advancement in the art to provide a single, continuous output, ion laser that was able to produce multiple specific wavelengths of light. It would be a related advantage to produce such an ion laser that did not require complex and tedious alignment procedures in order to produce the desired multiple light wavelengths, in that a multiple color coaxial output beam was produced. It would also be an advancement in the art to produce such a device that was capable of eliminating unwanted light wavelengths. It would be another advancement in the art to produce such an ion laser that was portable and inexpensive to manufacture. Such an apparatus is disclosed and claimed herein. BRIEF SUMMARY AND OBJECTS OF THE INVENTION The present invention is related to an ion laser that is capable of producing multiple output frequencies from a chosen group of frequencies. More particularly, the present invention is related to production of such an ion laser that is capable of producing selected and well defined light wavelengths. The laser is also capable of eliminating unwanted frequencies in order to prevent such frequencies from robbing power from the desired wavelengths. Using the present invention it is simple to adjust and select the specific desired output frequencies and output power by adjusting easily manageable operating parameters. These parameters include, for example, pressure within the laser tube. the percentage composition of each gaseous component, and operating voltage. In one preferred embodiment of the present invention, a combination of argon and krypton is used within the laser tube. Argon is known to produce a good blue laser beam in the 488 nm region. Blue is difficult to produce using many other laser media, including specifically krypton. Accordingly, the ability of argon to produce a blue output beam is of particular importance. Krypton also produces a blue output at 482 nm and 476 nm. However, the output of blue by krypton is found to be insufficient for many applications. Krypton in the ion laser environment, however, also produces strong outputs in red, yellow, and green wavelengths (647 nm, 568 nm, and 529 nm respectively) . Accordingly, access to each of these wavelengths is provided by the krypton - argon the mixture. In particular, the mixture provides for simultaneous outputs in the red, yellow, and blue frequencies, the most commonly used frequencies. As was mentioned above, certain light frequencies are unnecessary and undesirable. Production of these frequencies will rob power from the desired wavelengths. For example, it may not be necessary or desirable to produce a green output beam. The present invention, therefore, eliminates the undesirable wavelengths primarily through the optics used. If it is found that green is undesirable in a particular operating environment, optics may be chosen which transmit green. Typically optics are chosen which transmit at least ten percent (10%) and preferably more than twenty percent (20%) of the green, or other undesirable frequency. At this level of transmission, little if any lasing action takes place and the green is eliminated from the resulting output beam. The optics are chosen such that they reflect most of the desired wavelengths. For example, in one embodiment, the optics will transmit in excess of 20% of the green wavelengths, while reflecting in excess of 99% of the desirable red, yellow, and blue wavelengths. Thus, laser output is obtained in the red, yellow, and blue regions, but is prevented in the green region. Using the present invention the percentage of each output frequency can be adjusted by adjusting the gas mix, the pressure within the laser tube, and the voltage. This is important in view of the expected uses of the device. In many such uses it is desired to have an output beam which is comprised of several colors, each of approximately equal power. In many scientific applications, for example, outputs of blue, red, and yellow of approximately 5 mW are preferred. As will be discussed in additional detail below, if output of each of three colors of about 5 mW is desired, it is a simple matter, using the present invention, to adjust the composition of the gas mixture, the pressure in the laser tube, and the voltage in order to achieve the desired output. The present invention is easier to manufacture because of its ability to adjust the output. Furthermore, the device can easily be manufactured such that it is portable and can be air cooled rather than water cooled. This increases its usefulness in many settings, such as use in conjunction with a microscope or other delicate instrumentation. The present invention is also operable over a broad temperature range. At the same time, the present invention produces a multi¬ colored output which is coaxial. That is, there is a single output laser beam which contains multiple colors. Thus, it is not necessary to focus multiple output beams in order to have access to multiple colored laser beams. Accordingly, it is a primary object of the present invention to provide a mechanism for producing multiple colors of laser light while avoiding the problems encountered in the art. More particularly, it is a primary object of the present invention to provide a single mixed gas ion laser that is able to produce multiple specific wavelengths of light output. It is a related object of the invention to provide an ion laser that does not require complex and tedious alignment procedures in order to produce the desired multiple light wavelengths. It is also an object of the present invention to produce such a device which is capable of eliminating unwanted light wavelengths. These and other objects of the present invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the interior of an ion laser. Figure 2 is a graph illustrating the emission spectra of krypton and argon. Figure 3 is a graph illustrating the reflective gain discharge curve for argon. Figure 4 is a graph illustrating the reflective gain discharge curve for krypton. Figure 5 is a perspective view of one acceptable embodiment of a laser tube within the scope of the present invention. Figure 6 is a perspective view of a gas reservoir for use in conjunction with the laser tube illustrated in Figure 5. Figure 7 is a graphical representation of one embodiment of the optics usable within the scope of the present invention. Figure 8 is a graph showing acceptable transmission characteristics of the optics of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be more fully appreciated with reference to the drawings where like numerals designate like parts throughout. Referring now to Figure 1, an ion laser resonator is illustrated and designated 10. While a laser resonator 10 is used to illustrate the operation of the present invention, it will be appreciated that the present invention could be advantageously employed in a wide variety of different ion laser configurations. The resonator 10 is constructed of at least two spaced longitudinal members which are shown in Figure 1 in the form of a set of rods. As illustrated the rods run the approximate length of the resonator 10. In th« illustrated embodiment there are four rods, comprising a pair of lower rods 11 and a pair of upper rods 12, and form the structural foundation of the resonator 10. The rods 11 and 12 are joined together to form an integral structure by at least on spaced transverse member. In the illustrated embodiment there are a pair of end plates 14 which form the spaced transverse members. When the rods 11 and 12 are securely attached to the end plates 14, a laser cavity 16 is formed in the spaced defined by the rods 11 and 12 and the end plates 14. The end plates 14 form the basis for supporting the primary optical elements of the laser. The end plate 14 on one end of the resonator 10 acts as means for supporting a mirror 18, whose operation will become more fully apparent from the discussion below. The end plate 14 on the opposite end of the resonator 10 serves as a support for an output mirror 20, or other similar optical element. Located within the interior of the laser cavity 16 is an ion laser plasma tube 22. In one embodiment of the device, the plasma tube is constructed of ceramic and metal capable of high temperature cycling. The bore material may be any type of acceptable material, such as beryllium oxide. Beryllium oxide is found to have high thermal conductivity and low sputtering characteristics and is, therefore, useful for this purpose. It will be appreciated that the light beam necessary to produce the lasing action is achieved within the laser tube 22. As is well known in the art, ion lasers operate by exciting atoms or ions, such as argon, and then causing those ions to emit photons as they again return to the lower energy state. The emission of photons of a chosen frequency results in a coherent polarized light beam that can form the basis of the lasing action. This is achieved by means well known in the laser art, particularly means for producing a voltage in the laser tube. Also illustrated in Figure 1 is a mechanism for radiating heat generated by the operation of the laser tube 22, in the form of a copper heat sink 24. It may also be desirable to employ one or more fans 26 to cause cool air to flow over the heat sink 24 in order to carry accumulated heat away from the laser tube 22. The heat sink 24 is structured such that it exposes a large amount of surface area while occupying only a small space within the interior of the laser cavity 16. Conventional electronics can be employed in order to power the various features of the laser. Indeed the present invention is useful with many known and existing laser mechanisms. Thus, the electronics associated with the device will not be discussed in further detail, except to indicate that a direct current power supply 23 drives the ion laser. In operation, a light beam is produced by the laser tube 22. That light beam exits the laser tube 22 at either end along the optical axis formed by the bore of the laser tube. For ease of discussion it will be assumed that the beam travels first in the direction of the mirror 18. Once the laser beam encounters mirror 18 it is reflected back along the optical axis (the horizontal axis of the laser cavity 16) . The beam travels back into the laser tube 22 through the bore of the tube, initiating additional photon emission within the tube. The beam then continues out of the tube in the direction of the output mirror 20. As will be discussed in additional detail below, in the case of light of unwanted wavelengths, the output mirror transmits a high percentage (over 10%, and preferably over 20%) of the light. Thus, much of the light of unwanted wavelengths does not travel back through the laser tube, but exits the device. Accordingly, no lasing action takes place with respect to these unwanted wavelengths. The vast majority (over 99%) of the light of the selected desirable wavelengths is then directed back into the device, where the process is repeated numerous times. It will be appreciated that the output mirror partially transmits the light generated within the laser cavity. As a result, a portion of the beam exits the device. This exiting beam constitutes the useable laser beam. As discussed above, the present invention differs from conventional ion lasers in that multiple gases are employed in order to produce multiple selected colors within the output laser beam. For example, argon is known to produce a significant blue output at about 488 nm. This blue output is desirable and useful for numerous applications. At the same time, krypton is known to produce desirable and useful yellow (568 nm) and red (647 nm) laser output, as well a weaker blue output at 482 nm and 476 nm. Table I and Figure 2 show the representative outputs of argon and krypton lasers. The relative gain/discharge of a typical krypton laser is illustrated graphically in Figure 4. The relative gain/discharge of a typical argon laser is illustrated graphically in Figure 3. Thus, the present invention teaches the combination of multiple gases, such as krypton and argon, in the laser tube, in order to avoid the necessity of using two lasers to produce, for example, both a strong blue and additional red and/or yellow output. Table I. Representative Outputs Nominal 4 W argon laser Nominal 750 W krypton laser Wavelength (urn) Power (mW) 0.6471 300 0.5682 130 0.5309 100 0.5208 100 0.4825 50 0.4762 70 0.3507, 0.3564 200 (with special mirrors) In the present invention it has been found that mixtures of krypton and argon within a fairly broad range produce acceptable results. The precise mixture composition chosen will depend upon the desire output and the specific operating environment. It is generally found that argon in the range of from approximately 30% to approximately 45% of the total argon-krypton mixture produces acceptable results for most applications. It is found that by increasing the percentage of argon in the mixture, the blue output is increased, while the yellow and red output is decreased. Similarly, when the percentage of argon in the mixture is decreased, the yellow and red output is increased and the blue output is decreased. Thus, variation of the percentage mixture represents one method of adjusting the output of the laser. In addition, since argon is less conductive than krypton, increasing the percentage of argon in the mixture also results in a less conductive gas mixture. Table II illustrates some representative data obtained employing the present invention. It can be seen that variation of the pressure in the laser tube has a direct impact on which color(s) predominate. For example, reduction of the pressure generally results in an increase in the 476-488 nm blue bands, as a proportion of total output. Thus, if more blue is desired, pressure in the laser tube can be decreased. If less blue is desire, pressure in the tube can be increased. Table II also indicates that variation in voltage can also result in a variation in the output. Thus, varying the voltage is another direct method of adjusting the device to produce a desired mixture of output frequencies and output powers. Table II also indicates that by proper adjustment of the operating parameters, it is possible to achieve red, yellow, and blue outputs of approximately equal output power. As was discussed above, equal output powers in the 5 mW range (i.e. from about 4 to about 8 mW) are often desired. From Table II it can be seen that this is achievable at a number of different pressures, concentrations, and voltages using the present invention. Table II. Representative Experimental Results Percentage argon—30% Pressure Voltage Current Percentage argon—40% Pressure Voltage Current 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 Percentage argon—40% In summary, Table II shows that by varying the pressure, voltage, and the relative percentages of argon and krypton, output can be varied within predictable and desirable ranges. In the data presented, essentially all of the outputs measured were within the range needed for usable output beams of the selected wavelengths for most applications. Figure 5 illustrates the general construction of the laser tube 28 employed in a representative embodiment of the present invention. The cathode cap 50 is illustrated as being removed from the tube and the cathode end cap weld assembly is illustrated. On the opposite end of the laser tube 28, the anode end cap 52 weld assembly is illustrated. The laser tube 28 and its component parts are constructed in the same general manner as known ion lasers. The bqre braze assembly 54 is illustrated in the center of Figure 5. In one embodiment of the device the bore is constructed such that it is approximately 0.050 inches in diameter and 3.0 inches in length. The manner of construction of laser bores is known to those skilled in the art. 20 light that strikes the mirrored surface of reflector 62. The opposite side of the laser cavity is defined by a partially reflecting output mirror 64. Light is shown traveling through the area defined by high reflector 62 and output mirror 64, with a certain portion of the light exiting through output mirror 64. In this embodiment of the invention, output mirror 64 is comprised of an interior surface representing a one meter concave mirror and an exterior surface of a 31.5 cm convex mirror. The exterior surface aids in converging the beam as it exits the laser. The output mirror is also constructed such that it transmits a high percentage of unwanted light wavelengths. For example, for most applications it is desirable to eliminate the green frequencies. This is accomplished by known coating technology. Generally an ion beam deposit of an oxide coating is applied which reflects desirable wavelengths and transmits undesirable wavelengths, such as those in the green wavelengths. In one embodiment, optics are constructed whereby the transmission for the 488 nm blue light is approximately 1.5%. Transmission for the 568 nm yellow band is approximately 0.5% and transmission for the 647 nm red band is approximately 0.5%. Thus, a very high percentage of these wavelengths are reflected, resulting in efficient lasing action. At the same time, transmission of the 520-530 green bands is over 20%. Accordingly, there is insufficient reflection of the green wavelengths to provide adequate lasing action. The general performance of such a set of optics is graphically illustrated in Figure 8. In Figure 8 transmission is plotted on the vertical axis and wavelength is plotted on the 19 Figure 6 is an illustration of an optional gas reservoir 58. The anode end cap weld assembly 52a is illustrated and is essentially the same piece as is illustrated in Figure 5. The primary difference is the addition of portal 56 which is attached to the gas reservoir by means of tube 60. Thus, an additional source of gas is provided for feeding the laser tube. As a result, the gas reservoir 58 provides additional stability to the device during operation, as well as means for varying pressure within the laser tube. The pressure of the gas is stabilized by the additional volume provided by the attached reservoir. Accordingly, better long term performance and stability is achieved, as well as providing additional means for controlling pressure. In one embodiment of the device, the laser tube is designed to operate in TEMoo mode and to provide a polarized output beam. The laser tube is housed in an aluminum resonator structure of the typed described above. Laser head cooling is accomplished by using two high volume fans as illustrated above. Beam diameter l/e2 is 0.65mm and beam divergence if 0.95 mrad. Full angle polarization is less than 100:1 and mode, as mentioned above, is TEMoo. Another important feature of the present invention is the ability to eliminate unwanted wavelengths, while preserving desirable wavelengths. This is accomplished by design of the optics of the laser. Figure 7 is a schematic representation of one preferred embodiment of the optics. As illustrated in Figure 7, one end of the laser cavity is defined by a flat high reflector 62. High reflector 62 reflects essentially all of the horizontal axis. It can be seen that transmission for the desirable blue, red and yellow wavelencths is low, whereas transmission for the undesirable green wavelengths is high. In summary, the present invention provides a mechanism for producing multiple colors of laser light while avoiding the problems encountered in the art. The present invention also provides a single ion laser that is able to produce multiple specific wavelengths of coaxial light output. The present invention also produces a laser that does not require complex and tedious alignment procedures in order to produce the desired multiple light wavelengths. The present invention provides a device that is capable of eliminating unwanted light wavelengths. The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. What is claimed and desired to be secured by United States Letters Patent is:

Claims: 1. A constant output ion laser having the capability of producing laser output beams containing more than one predetermined frequency in the visible range, each said frequency having an output power within a predetermined range, said ion laser comprising: an ion laser tube, said ion laser tube containing a mixture of at least two gases; optical means disposed along at least one optical axis and defining an optical cavity, said optical cavity bounding at least a portion of said gas mixture; means for exciting said at least two gases contained within said optical cavity sufficiently to produce lasing, said exciting means resulting in a continuous output of laser light at at least two frequencies during operation of said laser; means for controlling the output power of each of said predetermined light frequency. 2. A constant output ion laser as defined in claim 1 wherein said means for controlling the output power of each of said predetermined light frequency comprises means for controlling the pressure within said laser tube. 3. A constant output ion laser as defined in claim 1 wherein said means for controlling the output power of each of said predetermined light frequency comprises means for controlling the operating voltage and current of said laser. 4. A constant output ion laser as defined in claim 1 wherein said means for controlling the output power of each of said predetermined light frequencies comprises means for varying the relative percentages of each of said gases in said laser tube. 5. A constant output ion laser as defined in claim 1 wherein said gases comprise argon and krypton. 6. A constant output ion laser as defined in claim 5 wherein said predetermined light frequencies comprising at least one red frequency, at least one yellow frequency, and at least one blue frequency. 7. A constant output ion laser as defined in claim 6 wherein the output power of each of said frequencies is in the range of from about 4 mW to about 8 mW. 8. A mixed gas ion laser comprising: a laser tube containing a mixture of at least two noble gases, said gases being chosen such that upon excitation, photons of at least two predetermined frequencies are emitted; an optical cavity bounded on opposite ends by optics such that if the gases within the laser tube are sufficiently excited, lasing occurs within the optical cavity at said predetermined frequencies; means for exciting the gases within the laser tube sufficiently that lasing occurs, said exciting means operating on direct current such that a constant output of laser light is produced; means for adjusting the output power of said laser such that light at said predetermined frequencies is emitted from said laser within predetermine power ranges. 9. A mixed gas ion laser as defined in claim 8 wherein said means for adjusting output power comprises means for adjusting the ratio of said noble gases to one another within said laser tube. - 10. A mixed gas ion laser as defined in claim 8 wherein said means for adjusting output power comprises means for adjusting the pressure of said noble gases within said laser tube. 11. A mixed gas ion laser as defined in claim 8 wherein said means for adjusting output power comprises means for adjusting the operating voltage of the laser. 12. A mixed gas ion laser as defined in claim 8 wherein said gases comprise krypton and argon. 13. A mixed gas ion laser as defined in claim 9 wherein argon comprises from about 30% to about 45% of the total gaseous mixture. 14. A mixed gas ion laser as defined in claim 10 wherein krypton comprises substantially the remainder of the gaseous mixture. 15. A mixed gas ion laser as defined in claim 8 wherein said optics are chosen such that they are substantially transmissive of unwanted frequencies. 16. A mixed gas ion laser as defined in claim 15 wherein said optics transmit more than approximately 10% of said unwanted frequencies. 17. A mixed gas ion laser as defined in claim 12 wherein said laser produces photons in the red, yellow, and blue frequency ranges. 18. A mixed gas ion laser as defined in claim 17 wherein said laser produces coaxial output beams in the red, yellow, and blue frequency ranges. 19. An ion laser capable of emitting light of more than one color comprising: an ion laser tube containing a mixture of at least two gases; optical means disposed along at least one optical axis and defining an optical cavity, said optical cavity bounding at least a portion of said gas mixture; means for exciting said at least two gases comprising a direct current power supply, said exciting means resulting in a continuous output of laser light at at least two frequencies; means for controlling the output power of each said frequencies comprising means for controlling the gas pressure within the laser tube, means for controlling the mixture of the gases within the laser tube, and means for controlling the direct current provided for exciting said gases.

Inventors: OSTLER KEVIN, OSTLER, KEVIN
Applicants: ION LASER TECH, ION LASER TECHNOLOGY
Application year: 1991
Main classification: H01S3
IPC codes: H01S3