3 papers
physics.optics2025
All-passive upconversion of incoherent near-infrared light at intensities down to 10 W/cm
Rabeeya Hamid, Demeng Feng, Pournima Narayanan +10
Frequency upconversion, which converts low-energy photons into higher-energy ones, typically requires intense coherent illumination to drive nonlinear processes or the use of exter…
physics.optics2025
Preventing overfitting in infrared ellipsometry using temperature dependence: fused silica as a case study
Shenwei Yin, Jin-Woo Cho, Demeng Feng +6
Fitting oscillator models to variable-angle spectroscopic ellipsometry (VASE) data can lead to non-unique, unphysical results. We demonstrate using temperature-dependent trends to…
physics.optics2025
Self-referencing photothermal common-path interferometry to measure absorption of Si3N4 membranes for laser-light sails
Tanuj Kumar, Demeng Feng, Shenwei Yin +12
Laser-light sails are a spacecraft concept wherein lightweight "sails" are propelled by high-intensity lasers. We investigated the near-infrared absorption of free-standing membran…