Előadó: Benjamin Klee (Wigner RCP SZFI)

Előadás címe: Directional white-light emitters powered by a low-power continuous-wave IR laser diode: Unexplained non-linear optical effects as a result of disorder

Dátum: 2022. június 28., 10:00

Helyszín: 1-es épület Tanácsterem, illetve online: https://wigner-hu.zoom.us/j/83609942103?pwd=VlJYcytQQ1BVSVZ0aEFQbWovenl… Meeting ID: 836 0994 2103 Passcode: 067877


A few years ago materials consisting of small molecules with a pseudo-tetrahedral structure have been found to exhibit a strong non-linear optical response to infrared laser irradiation: In a crystalline state, the well known second-harmonics generation (SHG) effect occurs while in an amorphous state instead a continuous spectrum covering the visible regime (hence appearing white) is observed. The most interesting property of this white-light generation (WLG) effect is that the low divergence of the exciting laser is retained during the process, providing a highly directional source of white light. Multiple materials have been found to exhibit this effect but still its existence in an unknown sample cannot be predicted and the mechanism of this effect is yet to be understood. In this talk, I will give an overview of the current knowledge of this active field of research. Since amorphicity seems to be a requirement for the WLG effect, I will focus on problems and progress regarding the structure determination of these materials.