Experimental and theoretical investigation of timing jitter inside a stretcher-compressor setup

Abstract

In an optically synchronized short-pulse optical-parametric chirped-pulse amplification (OPCPA) system, we observe a few-100 fs-scale timing jitter. With an active timing stabilization system slow fluctuations are removed and the timing jitter can be reduced to 100 fs standard deviation (Std). As the main source for the timing fluctuations we could identify air turbulence in the stretcher-compressor setup inside the chirped pulse amplification (CPA) pump chain. This observation is supported by theoretical investigation of group delay changes for angular deviations occurring between the parallel gratings of a compressor or stretcher, as they can be introduced by air turbulence.

Generation and Parametric Amplification of Few‐Cycle Light Pulses at Relativistic Intensities

“…However, as the effect is two orders of magnitude larger than the previously calculated value of 17 as [56], the presented considerations might be helpful for the proper design of jitter-stabilization systems for applications where other jitter sources have already been suppressed and where fs-precision is required, e.g. for the synthesis of few-cycle pulses.…”

“…4 in [56]) regarding the impact of pointing on the timing jitter is in our opinion not entirely correct. The missing aspect in their calculation is the non-collinear angle between the intersecting beams in the cross-correlation setup used to measure the jitter (cf.…”

“…* Note, that at the same time a direct contribution of beam pointing via geometrical elongation of the optical path outside the stretcher and compressor was excluded. It can be shown, however, that due to the non-collinear geometry of the diagnostic setup the calculated pointing-induced jitter of 17 as [56] underestimates the contribution by about two orders of magnitude. For details see Appendix A.3.…”

“…Since a system matching these demanding specifications is not commercially available, a set of amplifiers as well as a scheme for dispersion control were developed by Izhar Ahmad [53,54], Sandro Klingebiel [55][56][57], Christoph Wandt [58,59] and co-workers. In the following we will briefly summarize the essential ideas and setups and discuss the modifications we performed to further improve the system.…”

Optical beam transport to a remote location for low jitter pump-probe experiments with a free electron laser

“…The main part of the laser oscillator output seeds a chirped-pulse regenerative amplifier followed by a single pass amplifier, which delivers 100 fs range pulses with up to 7 mJ of energy per pulse. As it is known, due to the long effective path in the regenerative amplifier, the amplified pulses typically exhibit temporal drifts that may exceed few hundred fs [19] and could obviously be a problem for obtaining stable seeded FEL operation. So, as a first step of our work an active compensation of these drifts has been implemented.…”