Physical Review Research (Jan 2022)

Photon indistinguishability measurements under pulsed and continuous excitation

  • Ross C. Schofield,
  • Chloe Clear,
  • Rowan A. Hoggarth,
  • Kyle D. Major,
  • Dara P. S. McCutcheon,
  • Alex S. Clark

DOI
https://doi.org/10.1103/PhysRevResearch.4.013037
Journal volume & issue
Vol. 4, no. 1
p. 013037

Abstract

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The indistinguishability of successively generated photons from a single quantum emitter is most commonly measured using two-photon interference at a beam splitter. Whilst for sources excited in the pulsed regime the measured bunching of photons reflects the full wave-packet indistinguishability of the emitted photons, for continuous wave (cw) excitation, the inevitable dependence on detector timing resolution and driving strength obscures the underlying photon interference process. Here we derive a method to extract full photon wave-packet indistinguishability from cw measurements by considering the relevant correlation functions. The equivalence of both methods is experimentally verified through a comparison of cw and pulsed excitation measurements on an archetypal source of photons, a single molecule.