Research On The Performance Of High Efficiency Opticalsystem In Dual-mode Lidar

The laser device, detector and the optical system are the three factors that will infl-uence the performance of dual-mode lidar.As the laser device and detector have beenselected, it is important to study the optical system to improve the performance of the dual-mode lidar. The traditional structure of optical system in dual-mode lidar is refraction-reflection system, in which the center will be covered and the efficiency is low. The light splitting rate of the conventional beam splitter mirror is70%-80%, which still haveroom to improve.Anew optical system in dual-mode lidar will be designed based on the traditional structure.This thesis discusses the beam splitting method of system efficiency. Firstlyintroduces the working principle of the detection using beam splitter system, secondly,for laser and infrared small viewing Angle and low transmittance improved method isput forward, make the laser viewing Angle from the original3.5°to7°, infraredwavelengths of viewing Angle from the original6.9°and10.4°.Spectral transmittanceof system theory of laser rise from85.3%to99%, the system of infrared transmittanceof wave theory rise from85.9%to99%.This thesis also discusses the efficient design of a laser array receiving system.First of all, the analysis of the laser array receiving system. Then, the design of laserreceiving system, mainly containing the design of the optical fiber array, and the designof membrane structure. Finally, the analysis of the laser in the receiving system, microlens, and the coupling efficiency of optical fiber. When the longitudinal displacement,lateral displacement, angle offset within a certain range, the laser receiving system as awhole theory of coupling efficiency over93%.Main body structure of the dual-mode lidar optical system is analyzed in this thesis,in view of the center block, refraction type compound detecting total diameter structureis put forward, and complete the infrared optical system, laser optical system is anefficient design. Composite detection optical system of9.7μm infrared transmittanceraised from61.1%to66.3%,1.064μm laser system through rate raised from62.9%to72.7%, and the refraction system not to block center beam quality. By the simulation ofthe laser optical system, infrared optical system dispersion spot diameter17μm/22μm,respectively, are less than the bin size of the array detector, help to eliminate crosstalk,improve the overall efficiency.