Controlling circular polarization of light emitted by quantum dots using chiral photonic crystal slabs
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We study the polarization properties of light emitted by quantum dots that are embedded in chiral photonic crystal structures made of achiral planar GaAs waveguides. A modification of the electromagnetic mode structure due to the chiral grating fabricated by partial etching of the waveguide layer has been shown to result in a high circular polarization degree ρc of the quantum dot emission in the absence of external magnetic field. The physical nature of the phenomenon can be understood in terms of the reciprocity principle taking into account the structural symmetry. At the resonance wavelength, the magnitude of |ρc| is predicted to exceed 98%. The experimentally achieved value of |ρc|=81% is smaller, which is due to the contribution of unpolarized light scattered by grating defects, thus breaking its periodicity. The achieved polarization degree estimated removing the unpolarized nonresonant background from the emission spectra can be estimated to be as high as 96%, close to the theoretical prediction.
Lobanov , S V , Tikhodeev , S G , Gippius , N A , Gippius , N A , Maksimov , A A , Filatov , E V , Tartakovskii , I I , Kulakovskii , V D , Weiss , T , Schneider , C , Gessler , J , Kamp , M & Hoefling , S 2015 , ' Controlling circular polarization of light emitted by quantum dots using chiral photonic crystal slabs ' Physical Review. B, Condensed matter and materials physics , vol 92 , no. 20 , 205309 . DOI: 10.1103/PhysRevB.92.205309
Physical Review. B, Condensed matter and materials physics
©2015 American Physical Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at http://dx.doi.org/10.1103/PhysRevB.92.205309
This work has been funded by the project SPANGL4Q, under FET-Open Grant No. FP7-284743, and RFBR Projects No. 13-02-12144 and No. 14-02-00778.