Design Of Lightweight Optical Remote Sensing System By Binary Optical Technology

Binary optics is a new and developing branch of optics based on the optical wave diffraction theory, and a leading science formed by coupling optics and microelectronics. Binary optical element, also called diffractive optical element, has many advantages, such as small size, light weight, replicating easily, low cost, high diffraction efficiency, many design variables, wide range of optional materials, peculiar chromatic dispersion performances, and so on. Therefore it has been proved to be very useful in many practical applications, for instance ultra-precision manufacturing, optical fiber communication, image processing, biomedicine, national defense, and military affairs, etc. Applying binary optical technology on the optical remote sensing system can realize the reduction of system's size and weight, reduce the cost of system, make optical designer be flexible in materials'choice and can meet the requirement of modern optical system's design. With the aid of the modern advanced microelectronics, micromechanism and manufacturing techniques, binary optical technology can achieve more applications on aviation optical remote sensing system.The theories related to hybrid optical remote systems are investigated in this thesis, which mainly include the design of apochromatic refractive/diffractive hybrid system, design of achromatic and athermalized refractive/diffractive hybrid system, design of reflective/diffractive hybrid broad bandwidth telescope with very large aperture and analysis of the hybrid optical systems'performances. The main work can be summarized as follows:1. Based on the primary aberration theory, a method of correcting secondary spectrum is proposed. An apochromatic refractive system and an apochromatic refractive/diffractive hybrid system based on a binary optical element are designed under the concept of equivalent glass. The results show that comparing with the traditional apochromatic system, the size and weight of the apochromatic hybrid system can be reduced and the imaging quality is better, the MTF is more than 0.75, the maximal secondary spectrum is only 0.025mm,the correction ability is 10 times better than the refractive system's.2. An achromatic refractive system is designed utilizing the primary aberration theory. Applying a diffractive optical element on the refractive system is studied deeply and an achromatic refractive/diffractive hybrid system is designed. The imaging quality is excellent and the MTF is above 0.8 under natural temperature. By using athermalisation method, making optical materials'focal shift equal to assembly material's, the athermalized system can be realized. Then the athermalisation method is improved by the least square method. The performance of system can be stable within 20°~100°.3. Related theories of the telescope's eyepiece, objective and the structure of the system are researched in details. Based on achromatic math condition and Schupmann system, a reflective/diffractive hybrid telescope with very large aperture about 25 meters is designed, which utilizes a type of planed and transmissive diffractive element with very large aperture as objective. The MTF of the system is above 0.4,the size of diffuse spot is closed to the diffraction-limited spot's. Substituting ordinary diffractive lenses, multiorder diffractive lenses are introduced to improve the performance of the system, so telescope can get broader bandwidth. Result shows that, the telescope can provide nearly diffraction-limited imaging quality with either single-band, multiband or continuous coverage.4. The various optical performances and evaluating factors of the hybrid optical systems are studied deeply. An integrated set of theories which evaluate and analyze the systems are constructed. The diffractive efficiency of diffractive element, the effection on the optical system induced by environment and the tolerance of hybrid optical systems are analyzed.