Abstract

Cascaded slabs of birefringent crystals or prisms may be used to generate arrays of spots or to interconnect emitting, receiving, or modulating devices. The input light for each slab can be unpolarized, circularly polarized, or polarized linearly at 45° to the reference plane, which is defined as a plane that contains both ordinary and extraordinary rays. The output light for a given stage is then resolved into two linearly polarized orthogonal component polarizations. The crystal in the next stage is rotated by 45° so that each linearly polarized wave from the output of the previous stage has components parallel and perpendicular to the new reference plane. This process may be repeated with each stage, doubling the number of spots to be formed. The thickness of each crystal slab stage controls the displacement of the spots it creates. All the stages may be optically contacted or cemented to greatly reduce reflections and scatter. This technique may be particularly useful for subarray generation where a sparse regular array of beams (e.g., as produced by a microlaser array with relatively wide element spacings) can be transformed into a much denser spot array with approximately the same lateral extent.

© 1991 Optical Society of America