Circularly polarized lasing in chiral modulated semiconductor microcavity with GaAs quantum wells

Abstract

We report the elliptically, close to circularly polarized lasing at ω = 1.473 and 1.522 eV from an AlAs/AlGaAs Bragg microcavity with 12 GaAs quantum wells in the active region and chiral-etched upper distributed Bragg refractor under optical pump at room temperature. The advantage of using the chiral photonic crystal with a large contrast of dielectric permittivities is its giant optical activity, allowing to fabricate a very thin half-wave plate, with a thickness of the order of the emitted light wavelength, and to realize the monolithic control of circular polarization.PACS numbers: 71.36.+c, 42.65.Pc, 42.55.Sa Modern nanofabrication technologies allow to realize photonic structures -photonic crystals and metamaterials -with extraordinary optical properties 1-3 . In particular, chiral photonic structures are known to demonstrate a giant optical activity, several orders of magnitude stronger than natural materials 4-9 . Recently, it has been demonstrated that incorporating a chiral photonic structure into a planar GaAs waveguide or a semiconductor microcavity (MC) with embedded lightemitting achiral InAs quantum dots (QD) allows to achieve highly circularly polarized light emission, without applying magnetic field and without the need of thick quarter-waveplates 10-12 . The effect is due to the modification of the symmetry and density of environmentally allowed electromagnetic modes relative to that in free space due to the chiral nanostructuring, which, in turn, affects the spontaneous emission rate, directional pattern, and polarization 13,14 . This method has considerable advantages: small size, very simple operation, and compatibility with semiconductor fabrication process. In this Letter we demonstrate that the method works for the stimulated emission as well, and demonstrate a highly circularly polarized lasing from an AlGaAs/AlAs microcavity with chirally etched top Bragg mirror with GaAs quantum wells (QW) in the active cavity. To the best of our knowledge, previously the elliptically polarized lasing with a good degree of circular polarization with monolithic control of circular polarization was realized only on a quantum cascade laser in the THz range of frequencies 15 .A chiral photonic crystal (CPC) is fabricated from the AlAs/AlGaAs/GaAs high Q-factor MC grown by molecular beam epitaxy on a (001)-oriented GaAs. The full planar cavity consists of a lower and an upper Bragg reflectors with 27 and 23 pairs of AlAs/Al 0.20 Ga 0.80 As layers, respectively, with 3 nm GaAs smoothing layer after each pair in the Bragg reflectors and an active layer with three groups of four 13 nm GaAs QWs separated by 4 nm AlAs bariers. The nominal thicknesses of the AlAs and Al 0.20 Ga 0.80 As layers in Bragg mirrors are (68 ± 3) nm and (58 ± 3) nm, respectively. The Bragg pairs are deposited on the wafer with a slight wedge from the center to the circumference, resulting in a blueshift of the cavity resonance which can amount up to ≈200 meV.. It consists of the central group of four GaAs QWs with three AlAs barriers ...

Two-dimensional semiconductors in the regime of strong light-matter coupling

“…Second, both from fundamental and practical viewpoints studies of chirality effects for excitons in two-dimensional materials interacting with light are very promising in view of recent predictions of substantial natural optical activity in TMDC MLs stacks 110 . Furthermore, realizations of combined systems with TMDC MLs embedded in chiral cavities open up possibilities of realizing room temperature circularly polarized lasing 111 .…”

Random Lasing with a High Degree of Circular Dichroism by Chiral Plasmonic Gold Nanoparticles

“…For CPL generation via nano-sized devices, various types of two- and three-dimensional metamaterials have been developed. − Yet, the use of metamaterials invariably requires a complicated fabrication process with high precision. Other methods have also been suggested for direct generation of CPL, such as organic light-emitting diodes, vertical-cavity surface-emitting lasers, semiconductor quantum well lasers, and external-cavity lasers based on small organic molecules (SOMs). − However, most of the methods mentioned above share the same issue of a complicated and delicate fabrication process to achieve them. In particular, it is worth noting that SOMs are natural materials that possess chirality in their structures, thereby exhibiting circular dichroic properties: Cerdán et al have demonstrated CPL emission by utilizing SOMs in conjunction with an external laser cavity, with a luminescence dissymmetry factor between 0.1 and 0.2. , Although this type of device can yield CPL emission, SOMs naturally have relatively small CD quantified with an extinction dissymmetry factor in the order of 10 –4 –10 –2 , , and the use of the external laser cavity moreover hinders the possibilities for using it in direct nano-photonic applications.…”

Laser Ablated Nanocrystalline Diamond Membrane for Infrared Applications

“…In this work, we studied a diamond metamembrane with "chiral morphology" of surface patterns. It is well known that chiral structures have great possibilities in circular polarization filtering (see [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]). One example involves three-dimensional chiral photonic crystals that show giant circular dichroism in the near-infrared range due to their polarization-dependent photonic stop bands [ 47 , 48 , 49 ].…”

“…Unlike C symmetrical structures, metasurfaces with C symmetry demonstrate circular dichroism in transmission along the normal direction to the sample surface [ 52 ]. In references [ 41 , 42 , 43 , 44 , 45 ], the authors used C symmetrical metasurfaces to obtain the circularly polarized visible and near-infrared photoluminescence of semiconductor quantum dots. Due to the scalability of Maxwell’s equations, the wavelengths of optical resonances in C symmetrical metasurfaces can be shifted to the middle infrared by increasing their thickness and period.…”