High-conversion-efficiency optical parametric chirped-pulse amplification system using spatiotemporally shaped pump pulses.

High-conversion-efficiency, high-stability optical parametric chirped-pulse amplification is demonstrated with a spatiotemporally shaped pump laser system. Broadband 5-mJ pulses are produced at a 5-Hz repetition rate with a pump-to-signal conversion efficiency of 29% and energy stability better than 2% rms. To our knowledge this is the highest conversion efficiency and stability achieved in an optical parametric chirped-pulse amplification system.

Design of a highly stable, high-conversion-efficiency, optical parametric chirped-pulse amplification system with good beam quality.

An optical parametric chirped-pulse amplifier (OPCPA) design that provides 40% pump-to-signal conversion efficiency and over-500-mJ signal energy at 1054 nm for front-end injection into a Nd:glass amplifier chain is presented. This OPCPA system is currently being built as the prototype front end for the OMEGA EP (extended performance) laser system at the University of Rochester's Laboratory for Laser Energetics. Using a three-dimensional spatial and temporal numerical model, several design considerations necessary to achieve high conversion efficiency, good output stability, and good beam quality are discussed. The dependence of OPCPA output on the pump beam's spatiotemporal shape and the relative size of seed and pump beams is described. This includes the effects of pump intensity modulation and pump-signal walk-off. The trade-off among efficiency, stability, and low output beam intensity modulation is discussed.

One-way imaging with an aberrated reference beam.

We demonstrate image reconstruction by way of four-wave mixing for a signal that makes a single pass through a distorting medium. Both the signal and the reference originate from the same source and propagate through the same disturbance. In the four-wave mixing process, phase aberrations are subtracted out. A read beam from a second source reconstructs the undistorted image, yielding a phase conjugate without a double pass through the disturbance. Good reconstructed image fidelity is demonstrated for static distortions if the phase mismatch between the signal and the reference beams is minimized. If there is significant phase mismatch, reconstructed image fidelity is poor. We show that this technique can also be used to measure the autocorrelation function of the disturbance when the mismatch between the signal and the reference in the four-wave mixing scheme is varied.