Quantum Fourier transform spectroscopy of biexciton

TL;DR

This paper demonstrates quantum Fourier transform spectroscopy using biexciton photon pairs in CuCl, revealing spectral information through two-photon interference that differs from classical methods and offers new insights into exciton states.

Contribution

First experimental demonstration of two-photon quantum interference spectroscopy of biexcitons in a semiconductor, reconstructing spectra via Fourier transform of quantum interference patterns.

Findings

Reconstructed biexciton luminescence spectra from quantum interference data

Connected spectral features to exciton states in CuCl

Showed potential of quantum interferometry for solid-state spectroscopy

Abstract

Fourier transform spectroscopy with classical interferometry corresponds to the measurement of a single-photon intensity spectrum from the viewpoint of the particle nature of light. In contrast, the Fourier transform of two-photon quantum interference patterns provides the intensity spectrum of the two photons as a function of the sum or difference frequency of the constituent photons. This unique feature of quantum interferometric spectroscopy offers a different type of spectral information from the classical measurement and may prove useful for nonlinear spectroscopy with two-photon emission. Here, we report the first experimental demonstration of two-photon quantum interference of photon pairs emitted via biexcitons in the semiconductor CuCl. Besides applying Fourier transform to quantum interference patterns, we reconstruct the intensity spectrum of the biexciton luminescence in the two-photon sum or difference frequency. We discuss the connection between the reconstructed spectra and exciton states in CuCl as well as the capability of quantum interferometry in solid-state spectroscopy.