Observation of Analogue Dynamic Schwinger Effect and Non-Perturbative Light Sensing in Lead Halide Perovskites

TL;DR

This paper demonstrates that lead halide perovskites exhibit an analogue of the dynamical Schwinger effect, enabling non-perturbative light sensing and amplification, with potential applications in ultra-sensitive optical detection.

Contribution

It shows that methylammonium lead-bromide perovskite can exhibit the analogue dynamical Schwinger effect and can be used for non-perturbative electric field sensing and light amplification.

Findings

Observation of photoluminescence consistent with the analogue Schwinger effect.

Demonstration of non-perturbative light amplification in perovskites.

Potential for ultra-sensitive, broadband optical sensing.

Abstract

Dielectric breakdown of physical vacuum (Schwinger effect) is the textbook demonstration of compatibility of Relativity and Quantum theory. Although observing this effect is still practically unachievable, its analogue generalizations have been shown to be more readily attainable. This paper demonstrates that a gapped Dirac semiconductor, methylammonium lead-bromide perovskite (MAPbBr$_3$), exhibits analogue dynamical Schwinger effect. Tunneling ionization under deep sub-gap mid-infrared irradiation leads to intense photoluminescence in the visible range, in full agreement with quasi-adiabatic theory. In addition to revealing a gapped extended system suitable for studying the analogue Schwinger effect, this observation holds great potential for non-perturbative field sensing, i.e., sensing electric fields through non-perturbative light-matter interactions. First, this paper illustrates this by measuring the local deviation from the nominally cubic phase of a perovskite single crystal, which can be interpreted in terms of frozen-in fields. Next, it is shown that analogue dynamic Schwinger effect can be used for nonperturbative amplification of non-parametric upconversion process in perovskites driven simultaneously by multiple optical fields. This discovery demonstrates the potential for material response beyond perturbation theory in the Schwinger regime, offering extremely sensitive light detection and amplification across an ultrabroad spectral range not accessible by conventional devices.