# The interaction of twisted Laguerre-Gaussian light with a GaAs photocathode to investigate photogenerated polarized electrons

## TL;DR

This study explores how twisted Laguerre-Gaussian light interacts with GaAs photocathodes to produce polarized electrons, revealing polarization dependencies on wavelength, polarization state, and orbital angular momentum.

## Contribution

It demonstrates the generation and measurement of polarized electrons influenced by light's angular momentum components at specific wavelengths.

## Key findings

- Polarization of photogenerated electrons varies with wavelength.
- Orbital and spin angular momentum influence electron polarization.
- Near bandgap excitation enhances polarization effects.

## Abstract

The interaction of Laguerre-Gauusian light at select wavelengths from 690 to 810 nm with a p-type gallium arsenide (GaAs) photocathode photonic device and the production of photogenerated electrons was investigated. Spin angular momentum (SAM) and orbital angular momentum (OAM) were generated using linear or circular polarization and q-plates. The degree of polarization P from the photogenerated electron signal was measured. At an excitation of 695 nm ($E=1.78$ $eV$), $P_{OAM}=~2.1 \%$, $P_{SAM}=~1.3 \%$ and $P_{SAM, OAM (q=1)}= ~3.4\%$, whereas, at 800 nm ($E=1.55$ $eV$), near bandgap, $P_{OAM}=~-14.7\%$, $P_{SAM}=~-2.6\%$ and $P_{SAM,OAM (q=1)} = ~4.0\%$.