Zero-Order Beam Holographic Disk Test Method
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
This article describes a simple method for testing holographic optical elements (HOEs) to measure their diffraction efficiency and to locate gel defects. The equipment required to perform the method includes a laser, a fixture for mounting the HOE in the path of the laser beam, a solid- state video camera, optical elements for expanding a laser beam so that it fully illuminates the HOE, and a lens for focussing the zero-order or undiffracted portion of the beam passing through the HOE onto the detector array for the solid-state camera. The method includes the following steps: 1) The laser is energized before a HOE is brought into position. The solid-state camera captures a reference image of the laser beam. Both S and P polarization orientations can be recorded.