The Study On Detection Method Of Beam Parallelism Of Infrared System

In this dissertation, the various beam parallelism test methods was studied. Due to reduce the cost and enhance the resolution, for the measurement of large diameter optical device and system, the scanning pentaprism test method was utilized because of its special optical property that pentaprism makes the output light strictly perpendicular to the input light.An infrared collimation based on CCD detection device was designed to test the beam parallelism of infrared system. The optical system has been selected and designed. The measurement accuracy of the infrared collimator is up to 2 seconds.The testing device was mainly composed of a high surface accuracy and a guide rail with high straightness accuracy to measure the beam parallelism of large diameter collimator system which works on 1064nm wavelength and the diameter is Φ500mm. The beam under testing is divided by pentaprism into several sub-apertures to be tested in sequence. The light spot images of each sub-aperture have been captured by the combine use of infrared collimator and CCD detector, the centers of light spot have been obtained, the angle deviations could be figured out by the calculation of offset errors of each sub-aperture. Through processing and analyzing experimental data, the parallelism of large diameter infrared light could be evaluated.