Enhanced intensity variation for multiple-plane phase retrieval using a spatial light modulator as a convenient tunable diffuser

Abstract

In the multiple-plane phase retrieval method, a tedious-to-fabricate phase diffuser plate is used to increase the axial intensity variation for a nonstagnating iterative reconstruction of a smooth object wavefront. Here we show that a spatial light modulator (SLM) can be used as an easily controllable diffuser for phase retrieval. The polarization modulation at the SLM facilitates independent formation of orthogonally polarized scattered and specularly reflected beams. Through an analyzer, the polarization states are filtered enabling beam interference, thereby efficiently encoding the phase information in the axially diverse speckle intensity measurements. The technique is described using wave propagation and Jones calculus, and demonstrated experimentally on technical and biological samples.

Multiwavelength Absolute Phase Retrieval from Noisy Diffractive Patterns: Wavelength Multiplexing Algorithm

“…These BM3D filters are derived from the group-wise sparsity priors for the filtered variables. The derivation is based on the Nash equilibrium formulation for the phase retrieval instead of the more conventional constrained optimization with a single criterion function as it is in Equation (14). We do not show here this derivation as it is quite similar to developed in [32].…”

“…A dataset of recorded intensity patterns which is characterized by diversity of one or several parameters of the optical setup is a crucial moment of the phase retrieval problems. Defocusing and phase modulation are known as effective instruments in order to achieve the measurement diversity sufficient for reliable phase reconstruction (e.g., [12][13][14][15]). Various types of diffraction optical elements can be used for design of phase imaging systems [16].…”

Enhancing Multi-Distance Phase Retrieval via Unequal Interval Measurements

“…Moreover, the iterative method suffers from low convergence speed because the key issue in valid phase recovery is sufficient intensity variation. To facilitate a change in the diffraction intensity received by the sensor, speckle illumination [21][22][23][24][25][26][27][28][29][30][31][32] was proposed on the basis of SBMIR. However, speckle noise will cause aliasing and leakiness during the final reconstructions.…”

Lensless LED matrix ptychographic microscope: problems and solutions

“…To make full use of the dynamic range of the camera, a diffuser (randomly scattering medium) is placed on top of the aperture to introduce a range of random angles into the beam. Another benefit of using diffuser in the intensity measurement is the improvement of phase retrieval results [12] [13]. The measured diffraction patterns are then fed into a phase retrieval algorithm to produce the complex (both modulus and phase) image of the specimen.…”