| Setup for two experiments demonstrating phonon-enhanced nonlinearity in hBN, in transmission geometry. a Experimental setup for THG experiments. Detection is performed with PbS and MCT detectors, a lock-in amplifier, and boxcar-averaging. b Experimental setup for pump-probe FWM experiments. The time-delay is controlled by a mechanical delay stage with sub-1 µm step size. The pump and probe are both focused onto the sample with a reflective objective with 0.5 numerical aperture. Detection is performed with a silicon photomultiplier tube and lock-in amplifier. Credit: Nature Communications (2023). |
