Andreev Optoelectronics

TL;DR

This paper introduces a theoretical model for light interaction with Andreev bound states in superconductor--semiconductor junctions, revealing optical control and transduction capabilities that expand the potential for quantum device applications.

Contribution

It presents a novel model for light--Andreev interaction, enabling optical manipulation and microwave transduction of Andreev states in hybrid junctions.

Findings

Two optical absorption resonances separated by twice the bound state energy.

Optical pumping can populate or empty Andreev states, resetting the junction.

Andreev bound states can serve as optical--to--microwave transducers.

Abstract

Superconducting weak-link junctions host electron--hole hybridized excitations called Andreev bound states. These have attracted significant interest for the role they play in the device microelectronic operation and for quantum information applications. Andreev physics has so far been synonymous with the microwave range. However, the maturation of superconductor--semiconductor hybrid junctions opens the door to the characterization, and manipulation, of Andreev states by light. Here we introduce a model for light--Andreev interaction, with distinct features: Electrons transitioning into Andreev levels can sidestep Pauli exclusion, resulting in two optical absorption resonances separated by twice the bound state energy. One resonance populates the Andreev state and the other empties it; pumping both resets the junction and prevents saturation. Given their natural microwave coupling, we show how Andreev bound states can operate as optical--to--microwave transducers. We illustrate these effects with realistic device parameters. Our results highlight the possibilities in the new field of Andreev optoelectronics.