Ultrafast-nonlinear ultraviolet pulse modulation in an AlInGaN polariton waveguide operating up to room temperature

D M Di Paola,J.-F Carlin,Z Zaidi,I Shelykh,R Butté,D N Krizhanovskii,A V Yulin,N Grandjean,M S Skolnick,R P A Emmanuele,P M Walker,J Ciers

doi:10.1038/s41467-021-23635-6

Abstract

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. These rely on a strong intensity dependent (nonlinear) refractive index capable of modulating optical pulses on sub-picosecond timescales and on length scales suitable for integrated photonics. Currently there is no platform that can provide this for the UV spectral range where broadband spectra generated by nonlinear modulation can pave the way to new on-chip ultrafast (bio-) chemical spectroscopy devices. We demonstrate the giant nonlinearity of UV hybrid light-matter states (exciton-polaritons) up to room temperature in an AlInGaN waveguide. We experimentally measure ultrafast nonlinear spectral broadening of UV pulses in a compact 100 μm long device and deduce a nonlinearity 1000 times that in common UV nonlinear materials and comparable to non-UV polariton devices. Our demonstration promises to underpin a new generation of integrated UV nonlinear light sources for advanced spectroscopy and measurement.

Highlights

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing
Microresonator Kerr frequency combs[5] can provide high repetition rate pulse trains starting from continuous wave (CW) light, and supercontinuum generation provides light sources with octave spanning spectra[4,6]
UV pulse nonlinear modulation has not been observed in AlInGaN-based devices, despite the importance of AlInGaN for this spectral range

Summary

Introduction

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. Their excitonlike interactions lead to nonlinearity at least 1000 times larger than in weakly coupled semiconductors[28,29] This has allowed observation of nonlinear phenomena such as parametric scattering[30], superfluidity[31], solitons[32] and optical continuum generation[33] as well as quantum light sources[7,34]. The AlInGaN material system we use is highly robust and a mature and leading semiconductor technology for opto-electronics, with epitaxially grown wafers available commercially and strong excitonic optical transitions up to room temperature in the UV spectral range[36,37]. Our combination of high nonlinearity and room temperature operation in an on-chip device in a mature material system shows the great potential of AlInGaN-based polaritons for ultrafast nonlinear optics in the technologically important UV spectral range

Methods

Results

Conclusion