M.Sc Thesis


M.Sc StudentRabi Yaron
SubjectNovel Optical Imaging Techniques Using a Directional
Detector and Doppler Effect
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROF. Moshe Horowitz


Abstract

In this work we demonstrate two novel imaging techniques. The first technique is based on a directional detector. The output of the directional detector is affected only by light beams that propagate in a narrow angular window around a predefined direction. A light beam that propagates in another direction does not significantly affect the output of the detector. The directional detector is implemented using an interference effect and a finite width detector. The coherent detection used in the setup also enables to detect weak reflections from the object. The directional detector was analyzed theoretically and demonstrated experimentally. A reduced model was developed in order to estimate dependence of the system angular resolution on its parameters. A directional detectors array enables to reduce the effect of diffraction and scattering, and hence reconstruction techniques based on non-diffracting sources may be implemented. The second imaging technique we demonstrated theoretically is called Doppler imaging. We assume that the object contains several scatterers. The object is mounted on a rotary stage and it is illuminated by a monochromatic light. Due to Doppler effect, scatterers at different locations have a different Doppler shift. Due to the stage rotation, the Doppler shift of the reflected light changes in time. We apply the Gabor transform to obtain a time-frequency map of the detected signal. The result of the Gabor transform is used to reconstruct the object profile.