Оптический семинар. Зограф, Устименко

George Zograf (ITMO University)

'Stimulated Ramanemission from resonant silicon nanoparticle'

Abstract: All-dielectric resonantnanostructures emitting light have emerged as a novel platform fornanophotonics. Particularly, spontaneous Raman scattering enhanced in smallMie-resonant nanoparticles was successfully applied for in-situ nanothermometyduring nanoparticles heating for data storage and biomedical applications. Herewe demonstrate experimentally the transition from spontaneous to stimulatedRaman scattering in an optimized silicon nanoparticle with all dimensionssmaller than the wavelength of incident/emitted photons. The transition ismanifested as threshold-like nonlinear growth of Raman signal from a certainlevel of pumping cw-laser intensity. The smallest volume of silicon nanoresonatorsupporting stimulated is around 0.1 μm3 operates at the optical mode with aquality factor of around 100. Our finding paves the way for nanoscale Si Ramanlaser being prospective for multifunctional photonic nanodevices.

Nikita Ustimenko (ITMO University)

'All-dielectricmetalenses: properties and prospects'

Abstract: Optical metasurfaces, in a certain way structured arrays of dielectricor metal nanoparticles, are a subject of great interest to modernnanophotonics. The ability to arbitrarily change the wavefront and polarizationof the electromagnetic waves, the ultra-low thickness, unprecedentedfunctionality and high efficiency make metasurfaces one of the most promisingelements of electro-optical devices. One of such devices is a thin andlightweight lens – metalens. This report examines all-dielectric metalenses andits main features, possible applications and existing problems, discusses theprospects for the development and metalenses applications, and also givescomparison between metalenses and refractive lenses.