Study On Fourier Telescopy In Theory And Experiment

Fourier telescopy(FT for short) is an optical interference high-resolution imaging method mainly for remote and very dim targets, and as an important research direction in high-resolution imaging technology in the future, FT has broad application prospects. In this paper, several aspects both in theory and experiment have been researched and analyzed as follows:Firstly, the imaging principle of FT was deduced in detail, including how to modulate the target spatial spectrum information into the time-history signal, and how to demodulate the signal. Also with the characteristics of T-figurative configuration, the phase-closure algorithm on eliminating atmospheric phase distortion was clearly elaborated.Then the imaging process and a number of key factors were analyzed and simulated, particularly, on the mechanism of how to overcome the atmospheric turbulence. The simulation results show that when the transmitter aperture is at the size of about 10cm, high quality image could be reconstructed at the atmospheric turbulence condition of Cn² < 10^-13m^2/3 .At the same time, a new approach of processing the signal based on the all-phase Fourier transform for object reconstruction has been devised. Compared with the traditional approach, this method can avoid frequency errors of the reflected signal. So, it is of great advantage to applying FT to fast-moving targets, and to eliminating the piston jitter of atmospheric aberrations and the spectrum-shift error of acoustic-optic modulators, all of which lead to the frequency errors of signal.Finally, an experimental scheme based on diverging light has been put forward to verify the feasibility of this imaging technology and both of one and two-dimension objects have been reconstructed successfully in laboratory. Besides, there are several useful references for building field's FT system which could be offered by this scheme. Firstly, it simulated the T-figurative configuration properly, which is helpful to study the field transmitter array while the field's requirement is not mature. Secondly, the scheme is based on diverging light to illuminate the target. As consequences, on one hand, not only does it approach the practical situation, but also it makes the laser faculae overlap together on target's surface all the time, which is good at improving the signal-to-noise level of the reflected signal because the energy of the light was used at utmost. And on the other hand, it will be referential to aim the target and to avoid the atmospheric turbulence further more in field's system design.