Photonics Seminar

This seminar will focus on nonlinear optical phenomena in semiconductor optical microcavities and on a novel approach to back focal plane imaging.
In the first part, I will discuss optical bistability observed in CdTe-based microcavities. I will describe the preparation of transmissive optical microcavities using a water-assisted detachment technique, as well as the results of nonlinear transmission measurements performed with a tunable laser source. Two distinct types of hysteresis loops were observed experimentally, including a previously unreported form with an unusual direction and shape. A corresponding theoretical model will be presented that fully reproduces these features and confirms their physical origin.
The second part will be devoted to the fabrication and application of ellipsoidal polymer microlenses, which serve as high-numerical-aperture microscopic objectives printed directly onto the surface of photonic structures. I will outline the numerical design process based on ray-tracing simulations and the 3D microprinting fabrication technique. Experimental optical measurements will demonstrate that these microlenses enable momentum-resolved imaging over extended wavevector ranges that are otherwise difficult to access, particularly under cryogenic conditions. Finally, I will show that integrating such microlenses allows for simultaneous acquisition of multiple spatially resolved momentum-space images of exciton-polaritons (so-called multiplexed back focal plane imaging), while also reducing the excitation pulse energy required to reach the polariton condensation threshold.