Optical amplifier with two orthogonal zig-zag slab gain media for optical phase distortion compensation

摘要

An optical amplifier for use with a solid state laser which includes a pair of elongated slabs of a solid state lasing material, such as a rare earth doped yttrium-aluminum-garnet (YAG) crystal. Two embodiments of the invention are disclosed. In both embodiments of the invention, each of the elongated slabs is formed with a square or generally rectangular cross-section. The slabs are configured such that the longitudinal axes of the slabs are generally co-axial aligned and the slabs are orientated such that the major axis of the slabs are generally orthogonal. By configuring the two slabs to be orthogonal with respect to one another, the integrated thermal lens becomes azimuthally symmetric and can be compensated by a simple external lens. In addition, the negative lensing affect along the major axis of one slab is used to compensate for the positive lensing affect along the minor axis of the other slab and vice versa, thus minimizing the affects of the astigmatism. In an alternate embodiment of the invention, a dove prism is used to rotate the beam instead of rotation of the slabs. <IMAGE>