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We demonstrated a high-pulse energy, femtosecond-pulse source based on optical parametric chirped-pulse amplification. We successfully amplified 1-[micro]m broadband oscillator pulses to 31 mJ and recompressed them to 310-fs pulse duration, at a 10-Hz repetition rate. The gain in our system is 6 X [10.sup.7], achieved by the single passing of only 40 mm of gain material pumped by a commercial Q-switched Nd:YAG laser. This relatively simple system replaces a more complex Ti:sapphire regenerative-amplifier-based chirped-pulse amplification system. Numerous features in design and performance of optical parametric chirped-pulse amplifiers make them a preferred alternative to regenerative amplifiers based on Ti:sapphire in the front end of high-peak-power lasers. OCIS codes: 190.4970, 140.7090, 140.3280.

The design, manufacture and performance of laser diode array heatsinks is presented. Based on laminar flow microchannel cooling technology, the heatsink consists of diode bars individually fastened to chip carriers which are then attached to a back plane cooler. It thus maintains a low thermal impedance and efficiency for the cooling liquid's circulation. A proposed architecture for large two-dimensional laser diode arrays is also shown.

The design, manufacture and concepts behind a modular diode-pump source for lasers based on microchannel cooling technology are presented. The proposed pump packages were developed for direct high power pumping of slab lasers. They were tested for performance and efficiency on a neodymium-doped ytrrium aluminum garnet slab laser using a 20% subset of the 80 pump diode packages. It yielded 70 W of average power at 100 microsecond pulsewidths.

Advances in optical parametric devices, in particular those requiring high conversion efficiency, rely on pump laser and gain medium properties. We describe and theoretically model the source of dephasing due to angular deviation from ideal phase matching in optical parametric amplification. Real laser beams have angular content, which is described by their spatial frequency spectrum. Such beams cannot be treated as single plane waves in nonlinear interactions. Our mathematical model is based on a plane wave decomposition of Gaussian and top-hat beams into their components in spatial frequencies. Several popular nonlinear materials (beta-barium borate, lithium borate, and potassium dihydrogen phosphate) are examined for phase matching angles and dephasing is rigorously calculated. The impact of the beam angular content on small signal gain and on conversion efficiency in the strongly depleted regime is evaluated numerically. In addition, a criterion is formulated for beam quality tolerance in optical parametric amplifiers, for critical and noncritical phase matching. The impact of initial conditions in optical parametric amplification is considered. Our calculations are intended primarily for devices pumped with long (nanosecond) pulses. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]