Adaptive beam shaping using electro-optic micro-lenses, and hybrid acousto-optics

The control of laser beam shape is of great importance for many applications, such as imaging, telecommunications and materials processing. The ability to adaptively implement this process will add another degree of freedom to further enhance its modularity. In this work we explore two different techniques to achieve such goal.; In the first technique we implement and characterize adaptive electro-optic micro-lens array. By splitting the optical beam wavefront and/or distorting such wavefront, one can achieve beam shaping. We provide the basis for such systems using electro-optic microlenses. Since characterization of microlens arrays is quite challenging, the adaptive microlens characterization will provide another hurdle for rapid device prototyping. We introduce, for the first time, a simple technique that allow for in-situ characterization with minimum tools required. Using a simple z-scan we can determine the microlens focal length and characterize its aberration properties. We have used finite element analysis to model the lenslet array and found the model is in agreement with the measured data. We also address lens design and optimization issues to achieve aberration free optical system.; Second, we implement hybrid acousto-optics with feedback for beam shaping. We demonstrate that using electronic feedback one can obtain beam shaping in a hybrid acousto-optic device. Feedback as used and illustrated in the dissertation helps to generate the additional sound pressure which can give additional beam shaping. Previous analysis of hybrid acousto-optic devices with feedback have been restricted to plane wave treatments only. We show that over a region of convergence, one can achieve beam shaping by using the detected optical output and feeding it back electronically, together with the external radio frequency (RF) input signal. This is fundamentally different than just increasing the electrical input to the transducer. In general, we can also select, in this way, a certain range of spatial frequencies at the optical detector and use this for feedback purposes. We can selectively feed back a range of spatial frequencies of the optical beam, and hence have better control over the resulting beam shape.