title: Tunable single frequency thulium:YAG microchip laser with external feedback.
abstract: By use of the reflection of an uncoated external etalon, a diode-pumped thulium-doped YAG microchip laser was forced into a single-frequency mode. The wavelength of the single-frequency radiation was tunable over 15 nm simply by translation of the etalon relative to the laser. Output powers of 45 mW were achieved in a monolithic setup that is insensitive to vibrations. The origin of the single-frequency oscillation is the wavelength-dependent reflection of the etalon, which is coupled back into the laser resonator. This method permits the combination of inherently stable, single-frequency resonator geometries such as microchips with laser materials that have broad tuning ranges.
authors.affiliation: Institut für Laser-Physik, Universität Hamburg, Jungiusstrasse 9a, Hamburg 20355, Germany.
authors.forename: F F
authors.initials: FF
authors.lastname: Heine
authors.forename: G
authors.initials: G
authors.lastname: Huber