Acousto-Optic Cells with Non-Uniform Length of Light and Sound Interaction

G.A.Knyazev, V.B.Voloshinov (Department of Oscillation Physics, Faculty of Physics, Moscow State University, Moscow, Russia)

e-mail: volosh@osc162.phys.msu.su

The paper examines operation of acousto-optic cells designed with cross section of acoustic columns different from the traditional rectangular form. Generation in the cells of the acoustic  waves with the complicated cross section of the acoustic beams may be provided if driving  electrodes of piezoelectric transducers of the cells are fabricated in form of an ellipse, a rhomb  or with some other shape different from the rectangular one. It is evident that application of the  transducers possessing the complicated shape of the electrodes results in unequal lengths of light and sound interaction over cross section of an incident optical beam. The analysis proves that the unequal lenghts of light and sound interaction for the partial optical rays composing the  incident optical beam may cause some kind of smoothing and averaging of the cell transfer  function. Moreover, the non-uniform lengths of the interaction also provide suppression of side lobes if all the diffracted optical energy at the cell output is taken into account. As found, the  efficiency of the lobes suppression depends on the shape of the driving electrodes. Therefore, one obtains a relatively simple and unique facility to control and to suppress the level of the side  lobes. As proved, the desired suppression may be obtained by a corresponding design of the  piezoelectric transducers.


Section : 9