Femto Easy, ultrafast instrumentation

Fast FROG

Based on Second Harmonic Generation, Fast FROG is reliable and compact. Key design features, such as the wavefront division technique and the use of our mini imaging spectrometer MISS, make the Fast FROG very easy to use and versatile while leading to accurate measurements. Six models are available, covering different pulse duration ranges from sub-5 fs to 10 ps, over a broad spectral range. Two designs are available: one for long pulses mainly relying on transmission optics, and one for ultrashort pulses which is fully achromatic.

Features

  • Easy to use: no calibration and no tweaking necessary
  • User-friendly and powerful software (STAR : Software Technology for Acquisition and retrieval)
  • Can access Spatio-Temporal couplings (Spatial Chirp, Pulse Front Tilt)
  • Versatile: instant-swap of spectrometer for different wavelength ranges
  • Broad available spectral range (480 – 2100 nm)
  • Phase loop compatible with several pulse shaper for fast compression
  • Suitable for any repetition rate.
  • Single-pulse extraction possible up to 150 kHz laser repetition rate (with Enhanced detection option)
  • Sub-5 fs can be measured
  • Achromatic and non-dispersive (FC and FS models)
  • Fiber connector available (FC/APC, FC/PC)

Specifications

Fast FROG models FC FS PS1 PS3 PS5 PS10
Pulse duration range min 4 fs 10 fs 50 fs 100 fs 150 fs 300 fs
max 150 fs 250 fs 1 ps 3.5 ps 5 ps 10 ps
Accessible spectral range (nm) 480 - 21001 800 - 21001
Spectral Window Δλ (nm) 580 1 420 1 300 1
Input pulse repetition rate single-shot to GHz2
Single-pulse measurement Up to 150 kHz laser repetition rate (with Enhanced detection option, or 40 kHz without)
Min input pulse energy 3 Single-shot 250 µJ 1 µJ 1 µJ
1 kHz 10 µJ 100 nJ 50 nJ
50 MHz 20 nJ 1 nJ 200 pJ
1 GHz n/a 50 pJ 25 pJ
Input polarization linear horizontal or vertical
Detection CMOS 12 Bits - 3 Mpx - 72 dB
PC Interface USB 3.1 (or GigE as an option)
Beam height (mm) 69 - 148
Dimensions (mm) 326 x 194 x 129

1 Effective spectral bandwidth to be defined within the accessible spectral range according to customer’s requirements. Additional spectrometers can be provided to address different spectral windows.

2 The measurements are averaged over several pulses for laser with repetition rate higher than 150 kHz.

3 Those values give an order of magnitude, with "low energy" option when applicable. The exact sensitivity depends on many parameters (pulse duration, beam profile, wavelength...)

Options

Option Description
Additional crystals The default Fast FROG configuration includes one crystal. To extend the wavelength range of the device, additional plug&play crystals can be ordered and swapped within the system in seconds
Additional MISS spectrometer The default Fast FROG configuration includes one imaging spectrometer MISS. To extend the wavelength range of the device, additional plug&play MISS spectrometers can be ordered and swapped within the system in seconds
Enhanced detection Replacement of the default camera embedded in the Fast FROG by a higher performance one to increase the specifications of the system (better temporal resolution and spectral resolution, single pulse extraction up to 150 kHz)
Fiber input connector Plug&play collimation module with fiber connector. Can be mounted on the Fast FROG to easily switch the input from free-space to fiber. No alignment required.
High dynamic range Software mode to increase the dynamic of the Fast FROG signal acquisition from 12 to 16 bits. Not compatible with pure single-shot measurement as 2 images are necessary to build one FROG trace
Low energy Internal module to increase the sensitivity of the Fast FROG when the laser power is too weak
Phase loop Software mode to use the Fast FROG to perform spectral phase feedback loop with a pulse shaper (contact use to check pulse shaper compatibility)
Phase matching Default Fast FROG configuration works for a given central wavelength. Phase matching allows tuning the SHG crystal to measure different central wavelengths with the best SNR
Pulse Front Tilt / Spatial Chirp measurement Measurement of spatio-temporal couplings in the software. Correction of FROG trace accordingly for better accuracy of the retrieval
Small beam Internal module to increase the input beam diameter when it is too small for the Fast FROG (necessary for beams typically in the range of few mm or less)
Trigger Synchronization of the Fast FROG detection to an external signal for accurate laser single pulse extraction up to 80 kHz (150 kHz with the Enhanced detection option)

Software

Furthermore it is very user friendly, the Fast FROG software comes with an optimized retrieval algorithm, that allows you to retrieve time and spectral information in real time.
The image is a screenshot of the FROG software interface.

GigaHertz / low energy (pJ) measurement sample

FROG SEAM modelocked measurement example: 1.78 GHz rep. rate, 28 pJ per pulse, 50 mW avg. power
This is a FROG measurement performed with Fast FROG PS1 with a low energy option and small beam option.
The measured laser was a SESAM modelocked VECSEL developed at ETH Zurich1, assembled, amplified and CEO stabilized at the University of Neuchatel2.
This was the very first measurement of a GHz rep. rate Laser with a single-shot device.