GLAN LASER

The Glan Laser prism polarizer is made of two calcite prisms which are assembled with an air space. This polarizer is a modification of the Glan Taylor type and is designed to have less reflection loss at the prism junction. This polarizer is available with none, one, or two escape windows. The one without escape windows is made for low-energy lasers. The escape windows allow the rejected ordinary beam to escape out of the polarizer, which makes it more desirable for high-energy lasers. The polished faces of the side window are in the fragile cleavage plane of the calcite. The surface quality of these faces is relatively poor as compared to that of entrance and exit faces. No scratch dig surface quality specifications are assigned to these faces.

Unlike the Glan Taylor, this polarizer is made of non-UV calcite except by special order and is for use in the visible and near IR spectrum up to 2.3 microns. The angular polarized field of this polarizer is not symmetrical to the normal at the entrance face and is dependent on wavelength; e.g., at 1.4 microns, the semi-polarized field of a Glan Laser becomes almost zero on one side and 7 degrees on the other side of the normal. Therefore, for use at wavelengths longer than 1.4 microns, the polarizer should be tilted appropriately. If mounted, the polarizer is supplied appropriately tilted in the mount—the tilt results in a slight increase in Fresnel reflection loss at the uncoated air-spaced interface. A tilted and V-coated Glan Laser has transmission in the low 90% range at and around the narrow wavelength region of the coating wavelength.

Glan Laser polarizer with none, one and two escape windows are mounted in standard round mounts. Glan Laser Q-Switch is mounted in standard square mount. The polarized field F1 and F2 of all these is the same as shown in the plot below.