Optoelectronic Detecting Of Optical Properties Of Optical Transmit Antenna

Laser is one of the most important inventions of the 20th century. Since 1960, the first laser was invented in the world, it has attracted considerable attentions and is applied quickly for its characteristics of direction, coherence and intensity. Optical transmit antenna which works as a pivotal component in the laser system is paid more and more attentions. The primary function of the optical transmit antenna is to collimate far-field divergence of the laser beam and reduce the size of the laser beam in the far-field in order to increase the range of the laser action.After introduced a q parameter, the propagation of the laser beam in the common optical system is deduced in terms of the ABCD law. The characteristics of the Gaussian beam through a lens are summarized. Based on the feature of the Gaussion beam, requirements of the test system of the optical transmit antenna are given. Then according to the requirements, we design the test system and choose the devices for the experiment. The test system is set up. We also give the testing principles and the ways of the system to measure the transmittance, the magnification scale of the beam, the demagnification scale of the divergence and the adjustment of the object lens and the eye lens in the optical transmit antenna.Then, using the MATLAB software, the processing on the two original CCD images of the laser beam through and not through the optical transmit antenna is performed. After application the image enhancement (with histogram equalization and grey level adjustment ) and the image smoothing (with spatial equalization filtering, median filtering and Wiener filtering), we find they cannot remove the noise of the background. So we use the way of the threshold filtering to decollate the laser beam from the original image. Utilizing two kinds of methods, the threshold of the original image is obtained. Meanwhile, the original images are decollated with the binary level threshold and grey level threshold. The center of the mass and radius of the beam are calculated. The demagnification scale of the divergence of the optical transmit antenna is extracted. Finally, the transmittance and the magnification scale of the optical transmit antenna are also measured by the testing system.