DazScope^TM pulse optimization system

The DazScopeTM is a pulse controller system primarily designed to minimize the pulse duration of ultra-short laser systems characterized by amplified bandwidth (FWHM) ranging from 10nm to 50nm (i.e. transform limited durations ranging from 20fs to100fs).

Have a look to our DazScope specifications The Dazscope is sensitive to phase distorsions that are poorly characterized by autocorrelation techniques, as evidenced in the following simulations and experimental results

The DazScopeTM / DazzlerTM solution consists of a DazzlerTM pulse shaper located upstream of the amplifier, and of a compact optical head (non linear crystal, focusing optics and spectrometer, located after amplification, measuring the laser second harmonic spectrum (SHG spectrum).

In the pulse measurement step, the DazzlerTM is used to add pure second order phase to the pulse under study. The amount of chirp generated in the DazzlerTM is varied according to a well defined sequence, and the corresponding SHG spectra are recorded. The DazScopeTM software generates the chirp sequence and uses the observed SHG spectra to retrieve the pulse spectral phase. In particular, second, third and fourth order phase terms are precisely determined, and this measurement is fed back to the DazzlerTM for proper flattening of the pulse spectral phase. The key factor in retrieving high fidelity high spectral resolution phase measurements with the DazScopeTM / DazzlerTM integrated solution is the DazzlerTM ability to produce large and accurate chirps.

UPGRADE YOUR EXISTING LASER SET UP Since a significant number of CPA amplifiers now include a DAZZLER pulse shaper in their front-end, it is highly convenient to use the DazScope not only to correct but also to characterize the amplified pulses. Most techniques for characterizing the phase of short pulses can be divided into three successive steps: a linear filter, a non linear interaction (e.g. SHG) and a spectral measurement of the output. In the case of Frequency Resolved Optical Gating (FROG), the linear filtering consists in generating two time-shifted replica of the original pulse. Such a measurement can be easily reproduced with a DazzlerTM using acoustic waves to generate replicas of the optical pulses. However, in the case of pre-shaping in front of a CPA laser chain, methods that rely on pulse replicas are not favored. Indeed, the corresponding pulse structure will, in general, not propagate in the amplifier without being strongly distorted (e.g. a train of pulses will be obtained instead of two pulses) and may even cause major damage to the amplifier. Conversely, in the DazScopeTM approach, phase-only shaping is used, producing negligible non linear effects in a strongly chirped CPA amplifier.