Complete Pulse Characterization with the FROG Option available for pulseCheck Autocorrelators
pulseCheck and FROG Option
Second Harmonic Generation FROG is the most popular spectrometer-less Frequency-resolved Optical Gating method. Most of the pulseCheck autocorrelators by APE optionally integrate FROG and give access to complete pulse characterization. The addition of a special nonlinear crystal module and dedicated software opens the door to complete spectral and temporal pulse characterization. The FROG Option enables the pulseCheck to measure the spectral and temporal bandwidth and phase with just a few adjustments to the autocorrelator.
The FROG Option consists of:
- FROG crystal(s)
- A plane FROG mirror
- FROG measurement and retrieval software
Wavelength and Pulse Coverage
The various crystals available guarantee coverage of wavelengths from 420 nm right up to 2200 nm, of pulse widths from 20 fs to 6 ps, and a spectral resolution starting as high as 0.1 nm. For each crystal the software includes calibration data that enables to tune the crystal to a given
wavelength to achieve phase-matching. The Frequency-resolved Optical Gating option is designed for laser repetition rates above 10 kHz and is available for the pulseCheck autocorrelator series (except for SM models).
FROG Pulse Characterization Software
The software provides the laser pulse intensity as a function of time and frequency (wavelength). This is visualized in form of the common FROG trace diagram. With the implemented phase matching routine from pulseCheck, it only is a matter of seconds to automatically find the required phase matching tuning angle.
|FROG Crystals||Wavelength Range||Pulse Width Range||Spectral Resolution|
|VIS-I-200||420 ... 550 nm||200 ... 6000 fs||0.1 nm|
|VIS-I-50||420 ... 550 nm||50 ... 200 fs||0.3 nm|
|VIS-I-20||420 ... 550 nm||20 ... 70 fs||1 nm|
|VIS-II-150||550 ... 700 nm||150 ... 2000 fs||0.1 nm|
|VIS-II-50||550 ... 700 nm||50 ... 200 fs||0.3 nm|
|VIS-II-20||550 ... 700 nm||20 ... 60 fs||2 nm|
|NIR-200||700 ... 900 nm||200 ... 5000 fs||0.1 nm|
|NIR-50||700 ... 900 nm||50 ... 500 fs||0.2 nm|
|NIR-20||700 ... 900 nm||20 ... 50 fs||3 nm|
|IR-I-150||900 ... 1200 nm||150 ... 900 fs||0.2 nm|
|IR-I-60||900 ... 1200 nm||60 ... 200 fs||1 nm|
|IR-I-30||900 ... 1200 nm||30 ... 60 fs||5 nm|
|IR-II-100||1200 ... 1600 nm||100 ... 700 fs||0.5 nm|
|IR-II-50||1200 ... 1600 nm||50 ... 100 fs||2 nm|
|IR-II-30||1200 ... 1600 nm||30 ... 50 fs||9 nm|
|Ext. IR-I-50||1800 ... 2200 nm||50 ... 200 fs||19 nm|
Our FROG option is not available with the pulseCheck SM (Stepper Motor) series.
Please send us the serial number of your pulsecheck if you would like to upgrade an exisiting pulseCheck with FROG.
Email & Phone Contacts
APE has distributors around the world to give you the best support. Choose a country to find your local sales contact:
Retrieving Spectral and Temporal Phase
With the software, a FROG trace can be retrieved iteratively directly after recording the trace – or using a saved FROG trace. The raw measurement data are displayed in the “source frog trace” window of the software. The time and frequency axes are automatically rescaled to fulfill the relationship between time and frequency that is defined by the Fourier transformation. Additionally, the software will automatically optimize all start parameters for the retrieval algorithm. Thus, in most cases no additional user input is necessary.
A comparison of Frequency-resolved Optical Gating (FROG) with Spectral Phase Interferometry for Direct Electric-field Reconstruction (Spider)
In comparison with other pulse characterization methods, FROG Frequency-resolved Optical Gating offers some differences. The following table gives some aspects that could be considered.
- Optical setup similar to an Autocorrelator scheme
- Highly variable for different parameter ranges (pulse duration, wavelength)
- Direct sampling in the time domain possible
- Iterative fitting algorithm may make data interpretation more complex
- Measure spectrally broadband pulses in single shot mode often not possible
- Relatively complex setup
- Direct measurement in the spectral domain (amplitude and phase)
- Intrinsically single shot
- Insensitive to intensity noise
- Fast and direct reconstruction mathematics
- Unambiguous in the sign of the chirp and time
- Different parameter ranges often require an optimized single-setup