Linearly polarized remote-edge luminescence in GaSe nanoslabs

TL;DR

This paper reports highly linearly polarized remote-edge luminescence in GaSe nanoslabs, originating from out-of-plane dipoles converted via spin-flip, with polarization aligned toward the excitation spot, revealing new optical mode behavior.

Contribution

It introduces the observation of highly polarized remote-edge luminescence in GaSe nanoslabs and explains its origin through index-guided modes and dipole conversion mechanisms.

Findings

REL has a polarization degree above 0.90

REL is dominated by an index-guided optical mode

Out-of-plane dipoles are converted from in-plane dipoles via spin-flip

Abstract

We report highly linearly polarized remote luminescence that emerges at the cleaved edges of nanoscale gallium selenide slabs tens of micrometers away from the optical excitation spot. The remote-edge luminescence (REL) measured in the reflection geometry has a degree of linear polarization above 0.90, with polarization orientation pointing toward the photoexcitation spot. The REL is dominated by an index-guided optical mode that is linearly polarized along the crystalline $c$-axis. This luminescence is from out-of-plane dipoles that are converted from in-plane dipoles through a spin-flip process at the excitation spot.