Programmable generation of terahertz bursts in chirped-pulse laser amplification

Vinzenz Stummer,Edgar Kaksis,Audrius Pugžlys,Tobias Flöry,Gergő Krizsán,Andrius Baltuška,József András Fülöp,János Hebling,Gyula Polónyi

doi:10.1364/optica.403184

Abstract

Amplified bursts of laser pulses are sought for various machining, deposition, spectroscopic, and strong-field applications. Standard frequency- and time-domain techniques for pulse division become inadequate when intraburst repetition rates reach the terahertz (THz) range as a consequence of inaccessible spectral resolution, requirement for interferometric stability, and collapse of the chirped-pulse amplification (CPA) concept due to the loss of usable bandwidth needed for safe temporal stretching. Avoiding the burst amplification challenge and resorting to lossy post-division of an isolated laser pulse after CPA leaves the limitations of frequency- and time-domain techniques unsolved. In this Letter, we demonstrate an approach that successfully combines amplitude and phase shaping of THz bursts, formed using the Vernier effect, with active stabilization of spectral modes and efficient energy extraction from a CPA regenerative amplifier. As proof of concept, the amplified bursts of femtosecond near-infrared pulses are down-converted into tunable THz-frequency pulses via optical rectification.

Highlights

Laser pulse bursts with high energies up to multi-millijoules at various intraburst repetition rates have already found their way into a number of applications, such as materials processing[1], pulsed laser deposition[2], laser induced breakdown spectroscopy (LIBS)[3] and seeding of free electron lasers[4]
For high intraburst repetition rates, there exists a fundamental limitation of the achievable burst energy in conventional chirped pulse amplification (CPA) systems which prevents access to the multi-mJ regime
This limitation originates from the buildup of spectral modes that are mapped into the time domain as strong spikes on the temporal intensity profile of the stretched overlapping pulses circulating in the laser amplifier

Summary

Introduction

Laser pulse bursts with high energies up to multi-millijoules at various intraburst repetition rates have already found their way into a number of applications, such as materials processing[1], pulsed laser deposition[2], laser induced breakdown spectroscopy (LIBS)[3] and seeding of free electron lasers[4]. For high intraburst repetition rates, there exists a fundamental limitation of the achievable burst energy in conventional CPA systems which prevents access to the multi-mJ regime.

Results

Conclusion