Light Conversion Geco: Scanning Auto-correlator



  • Measures pulse duration in 10 fs – 20 ps range
  • Single set of optics for 500 – 2000 nm range
  • High resolution voice coil driven delay line
  • Non‑collinear intensity and collinear interferometric autocorrelation traces
  • Onboard pulse‑analysis software for pulse duration measurements
  • Integrated controller and computer
  • Non‑dispersive polarization control
  • FROG and FTIR ready

Operation of the Light ConversionGECO autocorrelator is based on noncollinear second harmonic generation in a nonlinear crystal, producing intensity autocorrelation trace directly related to the input beam pulse duration. One arm of the fundamental pulse is delayed by means of a magnetic linear positioning stage, providing fast, reliable motion with < 0.15 fs resolution. GECO can acquire a full intensity autocorrelation trace of 10 fs to 20 ps pulses and covers the full 500 nm to 2000 nm wavelength range.

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Thorlabs: Autocorrelator for Femtosecond Lasers

Autocorrelator Alignment A1 780

  • Ultrafast Pulse Width Characterization for 650 - 1100 nm
  • For Pulses from 40 fs to 1 ps, or Pulses Down to 15 fs with Precompensation
  • Selectable Gain up to 70 dB to Accommodate Large Range of Input Powers
  • Interferogram Signal Output through BNC
  • Scan Rate of 5 Hz
  • Compact Footprint: 6.90" x 5.53" x 4.82"

Thorlabs' FSAC Interferometric Autocorrelator provides approximate pulse width measurements in the 650 - 1100 nm wavelength range. Well suited for diagnostics of femtosecond Ti:Sapphire lasers, it consists primarily of a modified Michelson interferometer with a nonlinear detector at the output.

A BNC connector outputs the autocorrelation signal, which can be viewed on any oscilloscope with >1.5 MHz bandwidth. An example of the direct output from the FSAC is shown in the graph to the right. A photodiode amplifier with selectable gain from 0 dB to 70 dB provides compatibility with a large range of optical input powers, up to a maximum average power of 150 mW.

Intuitive, easy-to-reach controls on the outside of the enclosure allow the user to optimize the resolution and fringe contrast. The controls for the delay arm enable a full scan range of 50 fs to 10 ps (i.e., ±25 fs to ±5 ps), and a micrometer tunes the detector's position for maximum signal.

Interferometric Autocorrelator G1 780

This interferometric autocorrelation was obtained using teh Thorlabs Octavius® laser.  Precompensating Mirrors were used to chirp the beam prior to entering the autocorrelator.



Femtochrome manufactures state-of-the-art instruments for the characterization of ultrafast optical laser pulses.