Conventional optical elements have curved surfaces that necessitate light beam to be centered on the geometrical center of the optical elements (along with normal incidence) to avoid undue beam deflections, and thereby, avoid beam misalignment and distortions. In compact and portable optical devices, misalignment of the order of a few micrometers can cause significant operational issues. This strict dependency on beam alignment can be removed by designing optical elements with flat surfaces. We are working on design and experimental demonstration of flat optical devices operating in visible and infrared wavelengths.

Determining the transfer function of a reconstructive spectrometer using measurements at two wavelengths, Optics Letters, 48(14), 3753-3756 (2023).

Reconstructive Spectrometer using Photonic Crystal Cavity, Optics Express, 29, 17, 26645-26657 (2021).

Translationally Invariant Generation of Annular Beams using Thin Films, IEEE Photonics Technology Letters, 32, 1273-1276 (2020).

Surface and volume imaging without altering or disturbing the object under investigation is critical in semiconductor device development and medical diagnostics. We are working on developing optical techniques that enable imaging over large areas in a non-invasive manner. 

Diffraction Imaging of Cracks in Self-assembled Photonic Crystals, Optical Materials, 91: 189-194 (2019).