Temperature Dependence of Highly Excited Exciton Polaritons in Semiconductor Microcavities

Abstract

Observations of polariton condensation in semiconductor microcavities suggest that polaritons can be exploited as a novel type of laser with low input-power requirements.The low-excitation regime is approximately equivalent to thermal equilibrium, and a higher excitation results in more dominant nonequilibrium features. Although standard photon lasing has been experimentally observed in the high excitation regime, e-h pair binding can still remain even in the high-excitation regime theoretically. Therefore, the photoluminescence with a different photon lasing mechanism is predicted to be different from that with a standard photon lasing. In this paper, we report the temperature dependence of the change in photoluminescence with the excitation density. The second threshold behavior transited to the standard photon lasing is not measured at a lowtemperature, high-excitation power regime. Our results suggest that there may still be an electron-hole pair at this regime to give a different photon lasing mechanism.

Photoluminescence of high-density exciton-polariton condensates

“…2(b)]. As the highdensity regime is reached, the linewidth narrows again to the photon decay rate κ, a behavior consistent with current experimental observations [32,33] (See Supplemental Material showing additional experimental data). The mean number of cavity photons n ph and excitons n ex is shown in Fig.…”

“…The above cases have been restricted to the steadystate regime where a constant pump P LP is used. In a realistic experimental situation probing the high-density regime, a pulsed excitation is typically used in order to excite the condensate due to limitations in the laser power [32,33]. It is therefore a relevant question whether the inherent transient dynamics of the pumping gives any qualitative differences to the PL spectra.…”

Highly excited exciton-polariton condensates

“…ever, as presented in Ref. [21], the linewidth in the high excitation regime at 8 K is still much broader compared with that at 200 K.…”

Photoluminescence and gain/absorption spectra of a driven-dissipative electron-hole-photon condensate

“…(46) and (47) determined by Eq. (38), which char-acterizes the collective motion of the condensate, directly affects PL and gain/absorption spectra. As discussed in Ref.…”

“…This modifies the Berezinskii-Kosterlitz-Thouless scaling in equilibrium to the Kardar-Parisi-Zhang scaling, which was originally discussed in the context of randomly grown interfaces [25]. In addition, the nonequilibrium feature of the polariton system has brought considerable interest as to how a BEC state of polaritons may evolve into a standard semiconductor laser [19,20,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”