Microchip lasers

Microchip lasers are miniature diode-pumped solid-state devices formed by dielectrically coating thin platelets of gain media. Their simplicity and small size give them the potential for inexpensive mass production, while their cw output characteristics are comparable to those of the best conventional devices. By incorporating a thin platelet of a second material into the device, tunable cw lasers and picosecond Q-switched microchip lasers have been produced which outperform larger devices in many aspects. Electrooptically tuned devices have demonstrated a flat-band tuning response of 15 MHz/V at modulation rates from de to 1.3 GHz. Pulses as short as 115 ps, with peak powers of 80 kW, have been generated by electrooptically Q-switched microchip lasers, and pulse repetition rates as high as 2.25 MHz have been demonstrated. Passively Q-switched devices generate pulses as short as 218 ps and produce peak powers in excess of 130 kW, without the need for switching electronics. A variety of miniature nonlinear optical devices, including harmonic generators, parametric amplifiers, parametric oscillators, and fiber-based Raman amplifiers, have been used to frequency convert the output of these lasers, accessing the entire spectrum from 5 mu m to 190 nm in extremely compact optical systems. (C) 1999 Published by Elsevier Science B.V. All rights reserved.