Confocal paraboloids: some comments

Impact of an axial non-confocal antenna on the on-orbit lasercom receiver analyzed by the simplified combination method of ray tracing and diffraction theory

For an on-orbit lasercom receiver, the space thermal environment, microgravity environment and the adjustment error will deform the optical antenna, distorting the received wavefront and deteriorating the system performance. The axial non-confocal antenna is a deformed antenna caused by the despace of the secondary or primary mirror. Based on the simplified combination method of ray tracing and diffraction theory (simplified CMRD, or SCMRD), the calculation model of the normalized intensity distribution (NID) and the normalized received power (NRP) is established for an axial non-confocal antenna. The numerical results show that, the axial non-confocal antenna will flatten the received light spot, causing interruption of the communication link and deterioration of the bit error rate (BER) performance. The quantitative relations of the NID versus the axial non-confocal distance and the NRP versus the axial non-confocal distance would provide a reference for optical design, structural design, thermal design, assembly and adjustment accuracy design and detector selection. Besides, the numerical results are compared to those calculated by the wavefront fitting method and CMRD. The pros and cons of all methods are discussed. This work would advance the development of extending the SCMRD to analyze other deformed antennas' impact on an on-orbit lasercom receiver.

Inexpensive, high-quality optical relay for use in confocal scanning beam imaging

An inexpensive, high optical-quality relay lens made up of two eyepieces arranged in an afocal assembly for use in confocal scanning laser imaging is described. In the past we have used relays, within our confocal microscopes, made up of achromats with long focal lengths (> or = 10 cm), which take up large optical tracks and suffer from significant amounts of astigmatism and curvature of field. We quantify aberrations associated with achromat and eyepiece relays using CODE V optical design and analysis software. The eyepiece relay is found to be more compact, better corrected, and not significantly more expensive than its achromat counterpart. In addition to being used to interconnect two scanning mirrors optically as well as scanning mirrors with microscope objectives, it can form part of the optics in a confocal scanning laser MACROscope-Microscope system (Biomedical Photometrics, Inc., Waterloo, Ontario, Canada). Due to design constraints, the MACROscope-Microscope system cannot incorporate a conventional wide-field microscope into its structure such as is done in most commercial confocal microscopes. The eyepiece relay is used as a stand-alone, compact optical link between the scanning mirrors and the microscope objective. This consequently makes the MACROscope-Microscope system more compact and easier to commercialize.