Spontaneous Symmetry Breaking in a Polariton and Photon Laser

Abstract

We report on the simultaneous observation of spontaneous symmetry breaking and long-range spatial coherence both in the strong- and the weak-coupling regime in a semiconductor microcavity. Under pulsed excitation, the formation of a stochastic order parameter is observed in polariton and photon lasing regimes. Single-shot measurements of the Stokes vector of the emission exhibit the buildup of stochastic polarization. Below threshold, the polarization noise does not exceed 10%, while above threshold we observe a total polarization of up to 50% after each excitation pulse, while the polarization averaged over the ensemble of pulses remains nearly zero. In both polariton and photon lasing regimes, the stochastic polarization buildup is accompanied by the buildup of spatial coherence. We find that the Landau criterion of spontaneous symmetry breaking and Penrose-Onsager criterion of long-range order for Bose-Einstein condensation are met in both polariton and photon lasing regimes.

Optical control of spin textures in quasi-one-dimensional polariton condensates

“…A recent study shows that a transfer of the polarization of a nonresonant excitation laser to polariton condensates occurs for excitation powers slightly above the condensation threshold and that the transfer efficiency decays with increasing pump power [52]. We also profit from the former fact to nonresonantly create polariton condensates with a predominant circular polarization.…”

Room-Temperature Spin Polariton Diode Laser

“…However, it has been experimentally demonstrated that the orientation of this polarization is stochastic and hence the polarization cannot be experimentally recorded in the steady state [4,5]. Linear polarization can be observed in the steady state output only by pinning along a preferred crystallographic axis [6][7][8][9][10] and the degree of polarization decreases at high pumping levels due to the depinning effect caused by polariton-polariton repulsive interactions and self-induced Larmor precession of the Stokes vector of the condensate [11].…”

“…Information can be encoded onto both the intensity as well as the polarization of light in an optical communication system, thus effectively doubling the bandwidth of communication channels [27,30]. There have been several reports of excitonpolariton spintronic switches [31,32] and circularly polarized polariton lasers [5,[12][13][14]33]. In particular, Amo et al have demonstrated a non-local, all-optical exciton-polariton spin switch based on a pump and probe scheme in a semiconductor microcavity, wherein a localized trigger switches on a large pump area and thus controls the polarization of the full emission [31].…”

Динамика спинорной экситон-поляритонной системы в латерально сжатых GaAs микрорезонаторах при резонансном фотовозбуждении

“…Большинство исследований свойств поляритонных конденсатов до настоящего времени проводилось в усло-виях межзонного возбуждения [8][9][10][11]. В этих условиях возбуждаются свободные электроны и дырки в кванто-вых ямах в активной области МР, которые сначала свя-зываются в долгоживущие экситоны.…”

“…Кроме того поляритонные системы в отличие от бозе-конденсатных фаз холодных атомов допускают возможность формирования сильно неравно-весных макроскопически когерентных состояний, между которыми возможны неравновесные переходы, которыми можно управлять на масштабе микрометров и пико-секунд [7]. Наконец, дополнительная спиновая степень свободы у поляритонов ведет к экстраординарным свой-ствам как бозе-конденсата, так и его возбуждений, исследование которых представляет интерес не только с академической точки зрения.Большинство исследований свойств поляритонных конденсатов до настоящего времени проводилось в усло-виях межзонного возбуждения [8][9][10][11]. В этих условиях возбуждаются свободные электроны и дырки в кванто-вых ямах в активной области МР, которые сначала свя-зываются в долгоживущие экситоны.…”