Jan 2005Swamp Optics LLCRequest Info
Since the 1960s, ultrashort laser pulses have been measured using autocorrelators. Unfortunately, autocorrelators yield only rough measurements of the pulse length and give no information regarding the pulse phase (color vs. time) or its spatiotemporal distortions. Swamp Optics' Grenouille (GRating Eliminated No-nonsense Observation of Ultrashort Incident Laser Light E-fields) Model 8-20 not only measures the precise pulse intensity vs. time and frequency, but also yields the pulse phase vs. time and frequency, its spatial profile, and the two most important spatiotemporal distortions. It is also a simple and compact device requiring no alignment.
Grenouille is a simple version of frequency-resolved optical gating (FROG), a well-known and robust technique for measuring ultrashort pulses. Grenouille uses a Fresnel biprism to split the pulse in two and recombine the two (automatically aligned in space and time) in a thick second-harmonic-generation crystal. The thick crystal then gates one pulse with the other and also spectrally resolves the gated pulse, yielding a spectrogram of the pulse. Because spatiotemporal distortions in the pulse introduce characteristic distortions in the measured spectrogram, the instrument also can measure the two most important such pulse distortions: spatial chirp and pulse-front tilt; these are present in most ultrashort pulses but have gone unmeasured for many years. It can measure a single ultrashort pulse or a high-repetition-rate train of them.
The Grenouille Model 8-20 measures 700- to 1100-nm pulses of 20- to 200-fs duration and is less expensive than most autocorrelators.