用于高能激光系统的共孔径光学装置设计

Design of optical device with co-aperture for high energy laser system

高能激光系统的主要工作方式是利用其精跟踪模块将发射激光传输聚焦至闭环跟踪条件下的目标上,使之受到毁伤或失效。为实现该工作方式,本文研究设计了一套共孔径光学收发装置。该装置的发射系统主要由离轴两反式主望远镜模块、伽利略透射式调焦望远镜模块和光束馈送模块共同组成二级扩束系统,接收系统主要由离轴两反式主望远镜模块、精跟踪成像模块和光束馈送模块共同组成长焦距光学系统,其中光束馈送模块由二向色镜、快速反射镜等光学元件组成。以非相干空间合束的基模高斯光作为激光光源,利用光学设计软件对该装置进行了优化设计。对于发射系统,获得了激光经过调焦望远镜模块不同的调焦量调制后,传输至0.5~5 km处的光斑分布情况,且激光波前像差RMS值均优于λ/20;对于接收系统,由各模块一同构成的成像光学系统的性能经优化后接近衍射极限,其中系统传递函数在70 lp/mm时大于0.6,最后通过样机实验也验证了设计的正确性。本文的设计和实验结果证实了该共孔径光学收发装置结构合理,性能可靠,满足高能激光系统的工程应用需求。

The working principle of high energy laser systems is focusing the transmitting laser beam onto target while the target is tracked in a closed-loop using a fine tracking module,so that the target can be damaged or invalidated.In order to achieve this,an optical device with a co-aperture is designed for high-energy laser systems.The emitting system of this device is a two-stage beam expander consisted of an off-axis two-trans primary telescope module,a Galileo transmission telescope module for focusing,and a beam-feeding module.The receiver of this device is a long-focus optical system consisted of the same off-axis two-trans primary telescope module,an imaging module for fine tracking,and the same beam-feeding module,which is composed of a dichroic mirror,a fast mirror and other optical elements.Using an incoherent combination laser in space as laser source,we use optical design software in both the sequential mode and the non-sequential mode to design and simulate this device.The simulation results show that for the emitting system,the distribution of the spot at 0.5~5 km is obtained after the laser is modulated by different focusing quantities in the focusing telescope module.The RMS value of the laser wavefront is found to be better thanλ/20 in the emitting system.In addition,the performance of the imaging optical system approaches the diffraction limit after optimizing,and the system transfer function is greater than 0.6 at 70 lp/mm.A prototype experiment is carried out to verify the correctness and rationality of this design.The results of this paper confirm that this optical transceiver possesses reasonable structure and reliable performance,which meets the engineering requirements of high-energy laser system applications.