ИСТИНА

Embedding semiconductor light emitting nanostructures such as quantum dots (QDs) or quantum wells into chiral metasurfaces or photonic crystal slabs allows to create compact sources of circularly polarized light including lasers [1-3]. For example, a circularly polarized photoluminescence of achiral InAs quantum dots from a GaAs/AlGaAs waveguiding structure with chiral photonic slab was demonstrated, with a degree of circular polarization exceeding 95% [4]. Recently a close to circularly polarized lasing was reported [5] at room temperature and under optical pump from an AlAs/AlGaAs Bragg microcavity with GaAs quantum wells in the active region and chiral etched upper distributed Bragg refractor. A close to circular lasing of this structure was also demonstrated at low temperature in the exciton-polariton regime [6]. Chiral freestanding semiconductor structures such as shown schematically in the Figure can work in a metasurface regime, if the period of modulation is less than the light wavelength. In my talk I will discuss the physical mechanisms allowing to control the polarization state of light emission from photonic structures with chiral photonic crystals and metasurfaces. Figure: Shematic of a chiral waveguiding structure. One period of a square chiral grating of rectangular nanopillars is shown. Green color marks a semiconductor (e.g., GaAs), thin yellow layer shows the position of layer with light emitting QDs. References [1] K. Konishi, et al., Phys. Rev. Lett. 106, 057402 (2011). [2] A. A. Maksimov, et al., Phys. Rev. B 89, 045316 (2014). [3] S. V. Lobanov, et al., Optics Lett. 40, 1528 (2015). [4] S. V. Lobanov, et al., Phys. Rev. B 92, 205309 (2015). [5] A. A. Demenev, et al., Appl. Phys. Lett. 109, 171106 (2016). [6] V. D. Kulakovskii, et al., to be published.