Polarization states and output powers of a CO_2 laser with an electro-optic phase retarder

Abstract

We study the power output and polarization state of a CO(2) laser that contains both passive polarization-sensitive elements (Brewster plates) and an active phase-retarding electro-optic modulator (CdTe crystal). The theoretical threshold condition (i.e., the retardation required to extinguish the laser) is obtained from a cavity round-trip Jones matrix. We show that adding extra Brewster plates may be counterproductive in that the required retardation voltage increases. We calculated the output power, which depends on the saturated gain properties of the active media, by iterative modeling, with the elliptically polarized light propagated repeatedly around the cavity. We compare the theory with results from a folded rf-excited waveguide CO(2) laser (Laser Ecosse Model CM3500). Theory and experiment are in fair agreement for low powers. As expected, at high powers there are extra difficulties in modeling the cavity behavior, probably because of distortions induced in and by the crystal.

Fabrication of Achromatic Infrared Wave Plate by Direct Imprinting Process on Chalcogenide Glass

“…nfrared wave plates are necessary components for applications such as infrared imaging polarimetry and control of the polarization state of infrared lasers. [1][2][3] Currently, commercially available wave plates consisting of infrared transmissive crystalline materials, such as CdS and CdSe crystals, can accomplish the necessary phase retardation for infrared applications. 4) However, these crystals are very expensive.…”