Programmable Spectral Filter Arrays using Phase Spatial Light Modulators

Vishwanath Saragadam, Vijay Rengarajan, Ryuichi Tadano, Tuo Zhuang, Hideki Oyaizu, Jun Murayama, Aswin C. Sankaranarayanan

Abstract: Computational imaging has always benefited from tools that modulate light along the many dimensions of its plenoptic function. This paper provides a practical architecture for achieving spatially varying spectral modulation using a liquid crystal phase spatial light modulator (SLM). The use of a phase SLM, however, results in strong optical aberrations due to the unintended phase modulation, thereby precluding spectral modulation at high spatial resolutions. To mitigate this, we provide a careful and systematic analysis of the aberrations arising out of phase SLMs for the purpose of spatially varying spectral modulation; this analysis results in a dual strategy of “good patterns” that minimize the optical aberrations and a deep restoration network that overcomes any residual aberrations. We show a number of unique operating points with our prototype including single- and multi-image hyperspectral imaging, material classification (fewer than two images), and dynamic spectral filtering at video rates.