Perspectives on epitaxial InGaP for quantum and nonlinear optics

TL;DR

This paper reviews the emerging epitaxial InGaP platform's potential for advancing nonlinear and quantum optics, highlighting its high nonlinearity, low losses, and applications in quantum information processing.

Contribution

It provides a comprehensive overview of InGaP $ ext{chi}^{(2)}$ nonlinear integrated photonics, emphasizing recent experimental achievements and potential solutions to current limitations.

Findings

Achieved high-efficiency second-harmonic generation.

Enabled quantum nonlinear optics at the single-photon level.

Demonstrated broad applications in quantum information processing.

Abstract

Nonlinear optical materials are essential for the development of both nonlinear and quantum optics and have advanced recently from bulk crystals to integrated material platforms. In this Perspective, we provide an overview of the emerging InGaP $\chi^{(2)}$ nonlinear integrated photonics platform and its experimental achievements. With its exceptional $\chi^{(2)}$ nonlinearity and low optical losses, the epitaxial InGaP platform significantly enhances a wide range of second-order nonlinear optical effects, from second-harmonic generation to entangled photon pair sources, achieving efficiencies several orders of magnitude beyond the current state of the art. Moreover, the InGaP platform enables quantum nonlinear optics at the few- and single-photon levels via passive nonlinearities, which has broad implications for quantum information processing and quantum networking. We also examine the current limitations of the InGaP platform and propose potential solutions to fully unlock its capabilities.