Relaxation of mask design for single shot phase imaging with a coded aperture.
We present a method of relaxing the conditions of mask design in single shot phase imaging with a coded aperture (SPICA) for extending the applications of SPICA. SPICA, based on compressive sensing, enables the acquisition of wide, high resolution optical complex fields in a single exposure without the need for reference light. In our previous work on SPICA, a coded aperture (CA) was implemented with only amplitude modulation, resulting in a low transmission factor and low light efficiency because of the need for an independent phase retrieval process in the reconstruction. We attempt to alleviate these limitations by adapting a reconstruction algorithm to directly associate the phase retrieval process with a sparsity based reconstruction. With this approach, it is possible to realize SPICA with an amplitude modulation based CA having a high transmission factor, a phase modulation based CA, and a complex amplitude (amplitude and phase) modulation based CA. We verified the effectiveness of these relaxed CA designs numerically and experimentally.
Applied optics