Adaptive acousto-optic technique for femtosecond laser pulse shaping

Abstract

We discuss the theoretical and experimental investigation of acousto-optic dispersive tunable filters, based on quasi-collinear geometry of light-sound interaction in a tellurium dioxide single crystal. The geometry uses the effect of strong acoustic anisotropy in the paratellurite as well as peculiarities of acoustic wave reflections at the free boundary of the crystal. A mathematical concept for determination of optical, electrical, and constructional parameters of the filters is developed. Different experimental acousto-optic filters intended for femtosecond pulse shaping are designed and tested. Preliminary experiments are performed in a subpetawatt optical parametric chirped pulse amplification laser system. The experimental data conform completely with the predicted data.

eXawatt Center for Extreme Light Studies

“…To obtain the minimum (Fourier-transform-limited) duration of femtosecond pulses, a precise control of both the group velocity dispersion and the higher-order dispersions is required. For this purpose, an acousto-optic programmable dispersion filter [ 51 , 76 ] is used in the frontend (see Section 2.1). The pulse spectrum has a shape close to the 12th-order super-Gaussian.…”

Measurement of amplified binary-modulated chirped laser pulses generated by different acousto-optic pulse shaping algorithms

“…In this work, we report direct time-domain assessment of a programmable millijoule-level pulse source based on a high-resolution pulse shaper and a Ti:sapphire RA. Laser pulse envelopes were synthesized at the stretcher input with an AO dispersion delay line (AODDL) [17] and measured at the RA output with a picosecond-resolution streak camera [18,19]. It was found that the rise/fall time of chirped binary modulated laser pulses is affected by the sign of SOD introduced by acousto-optic diffraction in the AODDL.…”

Acousto-optical adaptive correction of a chirped laser pulse spectral profile in a Nd-phosphate glass regenerative amplifier

“…As a consequence, a short duration of the compressed pulse comparable with the initial one is expected. An acousto-optical light dispersive delay line (LDDL) is a convenient instrument for the desired modification of the spectrum of the chirped pulse [13][14][15][16].…”

“…Recently, LDDL devices have been used in high-power laser systems for pulse shaping. They are capable of controlling spectral amplitudes and phases in order to form the optimal spectral composition of the emission and compensate for higher-order dispersions [14][15][16]. The principle of collinear acousto-optical interaction of the electromagnetic wave in a crystal with frequency-and amplitude-modulated ultrasound underlies the operation of devices of this class [13].…”

“…A recent survey [20] covers modern aspects of ultrashort pulse control and compares LDDLs with other pulse shaping methods. Usually, the LDDL crystal is placed at the output of the master oscillator and thereafter the amplification of the chirped pulse takes place [16,21,22]. Thus, the device forms predistortions of the optical pulse, which means that optimal conditions must be ensured for pulse compression after it has passed through the amplifier chain.…”