Patent ID: 7535938
Filing Date: 2009-05-19
Classification: H01S

Abstract:
1. A monolithic microchip laser comprising: a first gain medium longitudinally pumped by a first laser beam from one end to produce a first fundamental wave linearly polarized; a second gain medium longitudinally pumped by a second laser beam from one end to produce a second fundamental wave linearly polarized along a direction orthogonal to the polarization of the first fundamental wave; a birefringent crystal, called beam-combining birefringent crystal, in which one of the fundamental waves is an e-ray and the other wave is an o-ray; and at least two nonlinear optical crystals for frequency conversion; wherein the birefringent crystal is sandwiched in between the gain media and the nonlinear optical crystals, all these crystals are optically bonded each other to form a monolithic structure, at least one nonlinear optical crystal is disposed at each side of the beam-combining birefringent crystal, at least one nonlinear optical crystal is optically bonded to the birefringent crystal, at least one nonlinear optical crystal is optically bonded to the gain medium; wherein frequency mixing takes place in one or more nonlinear optical crystal(s) optically bonded to the birefringent crystal; wherein the two fundamental waves are generated in two separate cavities, the resonant cavity that supports laser oscillation polarized normal to the principal plane of the birefringent crystal is linear while the resonant cavity that supports laser oscillation with polarization in the principal plane of the birefringent crystal is bent at each end faces of the birefringent crystal by an angle equivalent to the walk-off angle, the only common portion of the two cavities is the nonlinear optical crystal wherein frequency mixing of the first and the second fundamental waves take place; wherein the two pump beams are parallel to each other and are separated by a distance equal to the length of the beam-combining birefringent crystal multiplied by the tangent walk-off angle; wherein the pump beams are optically coupled to their corresponding gain media through any one of the followings: