Acousto-Optically Tunable Laser

摘要

Acousto-optical tuning has been implemented for an α-Al_2O_3: Ti~(3+) laser pumped by a 30 W Cu-vapor laser, which is a generator-amplifier system operating at 15,625 Hz, with a pulse duration of 50 nsec. The system can select an arbitrary laser wavelength in the IR range for approximately 64 usec. Experimentally the transformed IR beam has been varied in the visible and UV range. Recently, fempto-second tunable lasers have been used for fast-process spectroscopy. A Ti-doped sapphire crystal is used as an active element in such lasers. It generates optical beams in a range of 0.6… 1 μm. Usually, the second harmonic of a neodymium yttrium-aluminum garnet laser is used to pump the laser. The main generation line is 1.064 μm. The optical beam wavelength is usually tuned using a dispersive element, like a prism or grid, mechanically tuning it to the necessary wavelength. We propose to replace the prism with an acousto-optic filter for tuning. The time needed to change wavelengths is approximately 64 μsec, several thousand times faster than mechanical methods.