# Three dimensional trapping of light with light in semiconductor planar microcavities

## TL;DR

This paper demonstrates a method for full three-dimensional light trapping in a semiconductor microcavity using an all-optical approach, enabling tunable confinement through laser-induced refractive index changes at room temperature.

## Contribution

It introduces a novel all-optical scheme for 3D light trapping in a planar microcavity, controlled by laser excitation and thermal effects, with potential applications in light modulation.

## Key findings

- Strong 3D light trapping evidenced by spectral and spatial emission changes
- Laser-induced refractive index increase creates an effective photonic potential
- Thermal effects play a central role in the trapping dynamics

## Abstract

When light is confined in all three directions and in dimensions of the order of the light wavelength, full discretization of the photon spectra and distinctive phenomena occur, the Purcell effect and the inhibition of emission of atoms being two paradigmatic examples. Diverse solid-state devices that confine light in all three dimensions have been developed and applied. Typically the confinement volume, operating wavelength, and quality factor of these resonators are set by construction, and small variations of these characteristics with external perturbations are targeted for applications including light modulation and control. Here we describe full 3D light trapping, that is set and tuned by laser excitation in an all-optical scheme. The proposed device is based on a planar distributed Bragg reflector GaAs semiconductor microcavity operated at room temperature. Lateral confinement is generated with an attractive effective photonic potential tailored by the increase in the cavity spacer refractive index, induced by carriers photoexcited by a focused laser. Strong three dimensional trapping of light is evidenced by the laser-induced changes on the spectral, spatial, and k-space distribution of the emission. The dynamics of the laser induced photonic potential is studied using modulated optical excitation, highlighting the central role of thermal effects at the origin of the observed phenomena.