2123 4th St., Berkeley, CA 94710 Ph#: 510-644-1869, Fx#: 510-644-0118
e-mail: sales@femtochrome.com;
http: www.femtochrome.com

FR-103MN AUTOCORRELATOR
Specifications:* Resolution: ~ 1fs* Minimum Pulsewidth: < 5fs* Maximum Pulsewidth: ~ 40ps '* Scan Range: > 75ps '* Sensitivity: [PavPpk]min=10-7W2 "* Wavelength Range: 410-5000nm* Interferometric/Background-free* Crosscorrelation Option* Fiber Coupled/ Free Space* Low Rep Rate Option (> 4Hz)
* Computer Data Acqusition Option" 10-8W2 w/HS version. w/ PMT [550-1700nm]

The FR-103MN is a compact, dispersion-free, 'real-time' NL crystal autocorrelator for the measurementof temporal width of ultrashort laser pulses. Offering unsurpassed sensitivity, resolution and dynamicrange, it is easy to operate. The FR-103MN is perfectly suited for the monitoring of low power lasers
as encountered in optical communications, as well as ultrashort (fs/ps) pulses from any mode-locked
laser over UV-5000nm spectral range.

DISPERSION-FREE, HIGH RESOLUTION
Dispersion is negligible in the FR-103MN for pulsewidths down to ~5fs. Using high reflective
metallic-coated optics [the only transmissive element is an ultrathin (<<1um) pellicle beamsplitter], anunprecedented resolution approaching 1fs [limited only by the NL crystal thickness]is attained.

ROTATING PARALLEL (//) MIRROR ASSEMBLY
Rapid scan, periodic optical delay is introducedby means of a parallel (//) mirror assembly.*
This unique mechanism results in uniform anderror-free delay generation. Large delays areeasily generated, with dispersion-freeinterferometric resolution.

LINEARITY
The delay generated by the // mirror assembly is an exact sinusoidal function of time. The entire scan
range occurring within small angles, linear approximation is excellent. [The error in the measured
FWHM autocorrelation is < 0.5%, even for a pulsewidth as long as 40ps]. Optical delay generation isuniform, devoid of errors (position uncertainty) that can be encountered in other delay methods.
Furthermore, the autocorrelation delay axis can be linearized precisely by the numerical application of
the exact sine function.
The theoretical calibration factor (CF) of the FR-103MN is not prone to any change since the uniform
rotation rate of the // mirrors is crystal locked. Additionally, a translation stage w/micrometer featured
on the fixed arm of the Michelson Interferometer set-up allows the user to experimentally check andverify the CF.

_____________________________________*Z.A.Yasa and N.M.Amer, Optics Commun., V36, 406 (1981)

HIGH SENSITIVITY & DYNAMIC RANGE

The unmatched sensitivity of the FR-103MN is demonstrated by its noise equivalent signal level of[PavPpk]min = 10-7W2 *. This is further augmented by a dynamic range of ~104.

Commercial fiber laser (1552nm) pulse [450fs/ 1mW avg. power], measured by the FR-103MN.

WAVELENGTH RANGES (/BBO/KDP/IR/xxxx)

Three optimal NL crystals provide operation to ~ 5000nm. The standard unit comes with one NL
crystal, customer specified:/BBO/KDP/IR

410-600nm
510-1100nm
850-5000nm.

These NL crystals accept vertically polarized input beams, they are BBAR coated and fundamental
blocking filters are provided for their operational range. For long term reliability, a desiccators isprovided to protect the crystal when not in use. The standard NL crystal thickness is customer specified(0.1mm/0.3mm/1mm), with attention to the trade-off between resolution (thinner NL crystal) andsensitivity (thicker NL crystal).
Typically, a 0.3mm crystal thickness can be considered sufficient for pulsewidths down to ~30fs. With
shorter pulses, a thinner crystal is necessary. For sub 10fs pulsewidths, a custom (<25µm) NL crystal
thickness will need to be specified.

/xxxx PD modules for extended IR wavelengths
The photomultiplier (PMT) in the standard FR-103MN covers the 410-1800nm operation. This range
can be extended in the IR, by plug-in photodiode (PD) modules (/xxxx) which mount in front of thePMT enclosure. The PD module selections are:

/1100
/2200
/3000

1100-2200nm
2200-3400nm
3000-5000nm

Sensitivity is greatly reduced when operating with these PD modules since they lack the gain asprovided by a PMT. Typically, a minimum of ~ 5mW avg. power is needed for a subpicosecond
modelocked pulse, over the wavelengths covered by these modules.

OPTIONS:CROSSCORRELATION (/CC)
The FR-103MN has a built-in auxiliary port for crosscorrelation of two spatially separate synchronizedbeams. A fiber adapter can be installed also at the CC port [/FA(CC)].

INTERFEROMETRIC OPERATION (/IO)
Standard (Michelson Interferometer) configuration of FR-103MN
utilizes non-collinear (background-free) SHGmethod.* Optionally,
it can be converted to provide collinear (interferometric) SHG.
Using the highest resolution setting (<1fs) of its integration-timeswitch, fringe resolved autocorrelation is obtained. [This setting isof lowest gain, for which higher input power levels may benecessary].

FIBER ADAPTER OPTION (/FA)
An optional gimbal mount with a collimator is installed over the variable input aperture of the FR103MN, for easy connection of fiber-coupled beams. Factory aligned, repeated connections with noneed for realignment is facilitated. The /FA is easily removable for a free-space input beam. Its
standard adapter is FC [FC/PC or FC/APC]. For operation at 1550nm, a PM-DSF patchcord can beattached to the /FA. The collimator of the /FA is focus adjustable to obtain good collimation ifnecessary to use over a significantly wide wavelength range. A ƛ/2 plate holder is also provided within
the /FA assembly, for the user to install one for their wavelength of operation, if needed for polarization
control.
The /FA option can also be applied to the CC port [/FA(CC)].
____________________________________________________*

E.P.Ippen, C.V.Shank and A.Dienes, APL, V.21, p.348(1972

LOW REP RATE OPTION (/LRR)
The rotation rate of the // mirrors is locked ( phase locked loop) to the repetition rate (submultiple) of
the input beam. With a linear phase modulation superimposed on the rotation rate, autocorrelation
traces are readily accumulated (~ 15secs) and continuously monitored for any rep rate (> 4Hz) laser.
This mode is particularly useful for < 100Hz rep. rate lasers.
HIGH SENSITIVITY VERSION (/HS)
The standard uniform rotation of the // mirrors is modified in this version of the FR-103MN, by meansof a control mechanism. When this version (/HS) is selected, two modes of operation are available:
1. Uniform rotation (as in the standard FR-103MN, but with a lower refresh rate (typically 2Hz))
2. Controlled movement such that the // mirrors slow down greatly (4 selectable speeds ) over a period
when the pulses on the two arms of the Michelson Interferometer set up are overlapping. The// mirrors speed up outside this range, to return quickly for a repetition of the cycle.
Whereas the standard FR-103MN ( w/o LRR) provides 'real-time' autocorrelation for typically> 100kHz lasers, this version (FR-103MN/HS) renders the unit suitable for 'real-time' autocorrelationof lasers with any rep rate > 100Hz. This is particularly useful for kHz amplified lasers.
Higher sensitivity is also attained in this version, with its longer integration times available.
COMPUTER DATA ACQUISITION OPTION (CDA)
A data acquisition board is installed in the FR-103MN/CDA, providing an interface (USB) with any
PC w/ Windows OS. Its associated software allows traces to be displayed, analyzed [averaged and/orfit with typical pulseshapes (Gaussian and Sech2)] or saved.

SPECIFICATIONS:* Resolution: ~ 1fs* Minimum Pulsewidth: < 5fs* Maximum Pulsewidth: ~ 40ps
* Scan Range: > 75ps
* Sensitivity: [PavPpk]min=10-7W2 (w/PMT over 550-1700nm)* Wavelength Range: 410-5000nm* Interferometric/Noncollinear* Fiber Coupled/ Free Space* Crosscorrelation Option* Low Rep Rate Option (any rep rate > 4Hz)
* Computer Data Acqusition Option*(/HS)...High Sensitivity Version ('real-time' autocorrelation for >500Hz input rep rates)

2123 4th Street, Berkeley, CA 94710 Ph#: 510-644-1869, Fx#: 510-644-0118
e-mail: sales@femtochrome.com;
http: www.femtochrome.com