Direct Observation and Optical Manipulation of Exciton-polariton Parametric Scattering Lasing in Temporal
Junxing Dong, Si Shen, Jingzhuo Wang, Lisheng Wang, Yifan Zhang, Huashan Li, Xianghu Wang, Wei Gao, Yongzheng Fang, Hai Zhu
TL;DR
This work demonstrates direct observation and ultrafast optical control of non-degenerate exciton-polariton parametric scattering (PPS) lasing in a ZnO microcavity at room temperature. It uses resonant two-photon absorption with a near-IR femtosecond pump to excite the LP2 state and generate signal- and idler-states on LP1 and LP3 that satisfy energy and momentum conservation $\hat{E}_S(k_S)+\hat{E}_I(k_I)=2\hat{E}_P(k_P)$ and $k_S+k_I=2k_P$. An optical trigger seeds the PPS, delivering up to $6.91$ dB amplification and revealing a sub-picosecond response time of $0.4$ ps, enabling ultrafast coherent control. Coupled Gross–Pitaevskii simulations reproduce the PPS dynamics and phase matching, validating the platform for ultrafast polariton-based devices and PPS lasers.
Abstract
The hybrid light-matter character of exciton-polaritons gives rise to distinct polariton parametric scattering (PPS) process, which holds promise for frontier applications in polaritonic quantum devices. However, the stable excitation and coherent optical manipulation of PPS remain challenging due to scattering bottlenecks and rapid dephasing effect in polariton many-body systems. In this study, we first report the direct observation and optical amplification of non-degenerate intermode PPS lasing at room temperature (RT). The specific polariton branch of strong-coupled nanobelt planar microcavity is resonantly excited by a near-infrared (NIR) femtosecond laser via two-photon absorption (TPA) scheme, and the non-degenerate signal- and idler-states are stimulated. Angle-resolved dispersion patterns clearly reveal the evolution of the pump-, signal-, and idler-states under different excitation powers. Based on our self-constructed ultrafast femtosecond resonant optical trigger set-up, a selective enhancement and modulation of the signal-state is realized. Furthermore, the dynamic measurements of nonlinear signal-state enhancement process demonstrate a sub-picosecond response time (0.4ps), confirming its potential for ultrafast optical manipulation. Our work establishes a platform for exploring TPA-driven PPS laser and provides a novel optical modulation route for polariton-based optoelectronic devices.