Marcy Valley

Active tracker laser (ATLAS)

A high brightness diode-pumped, Nd-YAG solid state laser has been designed, fabricated, and tested. This phase conjugated master oscillator/power amplifier (MOPA) device produces 20-ns Q-switched pulses at 2500 Hz at an average power of 690 W and a beam quality of 1.1/spl times/DL when the pump diodes are operated at 27.5% duty cycle. With an external KTP doubler, this device has produced 175 W of green average power at a beam quality of 1.5 /spl times/ DL and a conversion efficiency of 45% over continuous operating times as long as one hour. This 1.06 /spl mu/m result is believed to be the highest average power brightness achieved, and the 532-nm performance is both the highest average green power and the highest average brightness ever reported.

Active Tracker Laser (ATLAS)

A phase conjugated Nd:YAG amplifier has demonstrated 690 W average power and 1.1 ×DL beam quality. The frequency doubled output was 175 W at 1.5 ×DL and 45% conversion efficiency. This is the highest average green power and highest average brightness reported.

Diode-pumped Nd:YAG laser for precision laser machining

Results are presented on a high power, diode‐pumped, pulsed Nd:YAG laser for precision laser machining. The laser is an unstable resonator with a graded reflectivity outcoupler, generating a beam with excellent beam quality. The gain medium is a single zig‐zag slab, pumped symmetrically by diode arrays. The use of diode arrays minimizes the thermal loading on the slab, and the zig‐zag path averages thermal distortions in the zig‐zag dimension. Measurements of beam divergence as a function of diode duty‐cycle will be presented. Available pulse formats will also be discussed. To date, the laser has produced 720 W at 20% diode duty‐cycle with a stable cavity and 550 W at 20% duty cycle with an unstable cavity in close agreement with model predictions. The beam divergence has been measured to be 1.7 times diffraction‐limited at 20% duty cycle. The laser has been operated with pulse lengths from 20 μs to 1 ms and is being used to obtain laser processing data, with some results shown.

Modeling high-brightness kW solid state lasers

Several kW-class solid-state lasers at TRW are described with an emphasis on the performance modeling used to aid development of high brightness operation. Comparisons of results and analysis are presented for key aspects of high power, diode pumped, Nd:YAG lasers and amplifiers that use zigzag slab configurations to minimize thermal effects. Devices described include multi-kW power oscillators suitable for high power machining, welding, and material processing; and phase conjugated master oscillator/power amplifiers (MOPAs) which provide short pulse, high brightness beams for active tracking, photolithography, or remote sensing. Laboratory measurements are in good agreement with predictions of diode pump profile and absorption efficiency; slab extraction efficiency and thermal load; and slab OPD.

A 900 W high-brightness diode-pumped Nd:YAG phase-conjugated laser

A short-pulse, single-mode, diode-pumped Nd:YAG laser based on phase-conjugated MOPA architecture produces 928 Watts at 2500 Hz with BQ~ 1.1 xDL.

Kilowatt-class diode-pumped industrial lasers

TRW is developing two diode-pumped Nd:YAG laser designs (called DP1 and DP2) for high-brightness laser machining. Two DP1 lasers have been built; one has operated at its design limit of 1000 W with a stable resonator, and the other at 55 W with an unstable resonator at reduced duty cycle, in agreement with model predictions.