Sub-250-mrad, passively carrier-envelope-phase-stable mid-infrared OPCPA source at high repetition rate.

An all-optical and passively carrier-to-envelope-phase-stabilized (CEP-stabilized) optical parametric chirped pulse amplification (OPCPA) system is demonstrated with sub-250-mrad CEP stability over 11 min and better than 100 mrad over 11 s. This is achieved without any electronic CEP stabilization loop for 160 kHz pulse repetition rate in the few cycle regime.

Optical parametric generation in CdSiP2.

We report efficient generation of picosecond pulses in the near- and mid-IR in the new nonlinear material CdSiP(2) pumped at 1.064 µm by an amplified mode-locked Nd:YVO(4) laser at a 100 kHz repetition rate. By using single-pass optical parametric generation in 8-mm-long crystal cut for type I(e→oo) noncritical phase matching, an average idler power of 154 mW at 6.204 µm together with 1.16 W of signal at 1.282 µm has been obtained for 6.1 W of pump at photon conversion efficiencies of 15% and 23%, respectively. Signal pulse durations of 6.36 ps are measured for 9 ps pump pulses.

Six-cycle mid-infrared source with 3.8 µJ at 100 kHz.

We report on the shortest pulses to date from a mid-IR optical parametric chirped pulse amplification: 67 fs duration with 3.8 µJ energy operating at 3.2 µm. The system is all solid state and diode pumped and operates at 100 kHz with unprecedented power stability of 0.75%rms over 30 min.

Ultrashort pulse characterization in the mid-infrared.

We describe a second-harmonic-generation frequency-resolved optical gating measurement device optimized for the characterization of few-cycle pulses in the mid-IR spectral range. The system has a temporal range of 100 ps with resolution of 0.12 fs, and it is capable of measuring pulses as short as 1.5 cycles (15 fs) at 3 microm. Through interchangeable beam splitters and detectors it covers a wavelength range from 800 nm to 5 microm with up to 0.5 cm(-1) resolution. We demonstrate measurement of a richly featured 3.2 microm pulse with 9.6 cycle duration, recovering the main pulse of 96 fs, as well as low-intensity post-pulses with picosecond offset. We also characterize a 100 fs pulse after dispersion through a 1 cm sapphire plate, comparing the measured phase difference with the calculated one.

Design and simulation of few-cycle optical parametric chirped pulse amplification at mid-IR wavelengths.

We present a design for a novel carrier to envelope phase stable optical parametric chirped pulse amplification source in the mid-infrared. We calculate the amplification of a 3.1 microm seed pulse, generated via DFG from a two-colour fibre laser, using a fully three dimensional OPCPA code. We combine this with a ray-tracing code to model pulse compression using a grating compressor and a deformable mirror for programmable phase compensation. The simulation models the complete system based on FROG measurements of the commercially available fibre laser, ensuring the simulation is realistic. The obtained results indicate energetic pulses of 56 fs duration, corresponding to 5.2 cycles, can be produced with calculated pulse energies of up to 9.6 microJ at a central wavelength of 3.3 microm.

Mode-locked ring lasers for the backscattering measurement of mirrors.

A new method for measuring the backscattering produced by mirrors is presented. A mode-locked ring laser allows us to achieve more sensitivity than with any other technique. The present sensitivity to a minimum intensity backscattering coefficient (ratio of backscattered versus incident intensity) of 10(-15) can be enhanced through stabilization. We compare results realized with this technique with results issued from classical bidirectional reflectance distribution function measurements.