Microchip lasers and applications*

Microchip lasers are small solid-state lasers characterized by short resonator lengths (~1 mm) and monolithic flat-flat cavities. The first feature enables solid-state lasers operating in new performance regimes while the second attribute allows inexpensive fabrication of the devices in robust packages. In the simplest of these devices, cw lasers, the laser is fabricated by polishing a wafer of gain medium with surfaces that are flat and parallel with a thickness of the desired resonator length. Resonator mirrors are deposited on the polished faces to form the cavity and then the wafer is diced. Devices with more functionality are fabricated by using two wafers to form the laser, one of which can be an electro-optic material or a saturable absorber material, that are bonded together. Frequency-modulated (>1.3-GHz modulation bandwidth) and Q-switched lasers (220-ps-long pulses with passive Q-switching) have been demonstrated using these techniques.