Research On Typical Imaging Features Of A Photon Sieve

Photon sieve is a new class of diffractive optical element, consisting of a great number of pinholes properly distributed over the Fresnel zones. The photon sieve has many imaging advantages and structural advantages: A photon sieve is able to suppress the side lobes and other diffraction orders which is good for reaching higher imaging contrast; A photon sieve has a higher spatial resolution with the same feature size and overcomes the limitation which is caused by the minimum feature size; A photon sieve is small and lightweight, requires no additional support structures.The photon sieve also has image defects: 1) In the imaging process, the photon sieve has obvious achromatic property; 2) The clear aperture of photon sieve greatly decreases, and diffraction efficiency is lower. This paper will research the imaging features of photon sieve from several aspects, including achromatic property, diffraction efficiency and imaging contrast. The structure parameters of a photon sieve are also studied in this paper to analyze the relationship between focusing properties and different structures. The contents and the innovation can be generalized as:1. The imaging theory of the photon sieve. The scalar and vector diffraction theory are applied to analyze the optical transmission, focusing properties of Fresnel zone plate and photon sieve. By analyzing imaging characters, we obtain the method to design the photon sieve including the exact selection conditions of the pinhole size and radial position.2. Analyzing the achromatic property of the photon sieve. Photon sieve suffers from large chromatic aberration, therefore, all those photon sieves can work only at a designed single wavelength. By using refraction lens,we design a chromatic aberration compensation system. This system is able to realize a continuous broad spectral range imaging and focusing. We analyze the focusing properties of this diffractive-refractive hybrid imaging system from theory and simulation, testifying the correctness of this system. Meanwhile, the photon seive is used more widely.3. Imaging properties of composite photon sieve.The diffraction efficiency of photon sieve is lower, so we propose a new kind of photon sieve, which combining zone plate with photon sieve. The theoretical analysis and experimental analysis are displayed. Compared with traditional photon sieve, the composite photon sieve not only improves diffraction efficiency but also increases imaging contrast and depth of focus. By studying the structure parameters of composite photon sieve, we obtain the factors that influencing imaging quality.4. This paper proposes an idea that replacing traditional photon sieve with composite photon sieve in telescope system, which can make imaging quality of the new telescope system better.