Assembly and method for preventing depolarisation of linear polarised light when transilluminating crystals

摘要

A solid-state laser or a gas laser comprises crystals having a {111} or {100} crystal plane and a [111] or [100] crystal axis. Surface of the crystals is formed by the crystal plane onto which the linear-polarized light impinges at an angle of 45-75[deg] . The crystal is disposed so that the light after entering the crystal propagates as parallel as possible to the crystal axis and/or that a system for preventing the formation of a temperature gradient in the crystal comprises a tempering unit. The light impinges at a Brewster angle. The laser comprises a light producing unit for producing coherent intensified light by a stimulated emission. The light producing unit comprises an optical resonator cavity containing a laser-active medium and having window(s) for out-coupling laser light; and an energy pump for producing laser transition regions in the active medium as well as optionally other optical elements irradiated by laser light. An exit window of the resonator and/or the other optical elements irradiated by the laser light comprise a crystalline material that is arranged so that the crystal plane forms the surface onto which the laser light impinges and that the laser light propagates within the crystal as parallel as possible to the crystal axis. The laser includes a tempering unit for the exit window and/or for the optical elements irradiated by the laser light. The tempering unit prevents the formation of temperature gradients in the direction of the light path in the exit window and/or in the optical elements irradiated by the laser light. The tempering unit prevents the formation of the temperature gradient in all spatial directions, and produces at least the temperature of the hottest spot in the irradiated material. The tempering unit comprises a Peltier element and/or a temperable gas stream and/or a heat radiator. An independent claim is included for a method of preventing and/or minimizing the depolarization of linear-polarized light during the transmission of light through the crystals having the crystal plane and the crystal axis, comprising using the crystal plane as the crystal surface onto which the polarized light impinges and orienting the crystal so that the linear-polarized light impinges on the crystal surface plane at an angle of 45-75[deg] and the light propagates in the crystal as parallel as possible to the crystal axis and/or so that the formation of a temperature gradient in the crystal is prevented by the tempering unit.