Absorption spectroscopy at the ultimate quantum limit from single-photon states

Beccie Solweling Whittaker, Chris Erven, Alex Neville, Monica Berry, Jeremy O'Brien, Hugo Cable, Jonathan Matthews

Research output: Contribution to journalArticle (Academic Journal)peer-review

36 Citations (Scopus)
329 Downloads (Pure)

Abstract

bsorption spectroscopy is routinely used to characterise chemical and biological samples. For the state-of-the-art in laser absorption spectroscopy, precision is theoretically limited by shot-noise due to the fundamental Poisson-distribution of photon number in laser radiation. In practice, the shot- noise limit can only be achieved when all other sources of noise are eliminated. Here, we use wavelength-correlated and tuneable photon pairs to demonstrate how absorption spectroscopy can be performed with precision beyond the shot-noise limit and near the ultimate quantum limit by using the optimal probe for absorption measurement—single photons. We present a practically realisable scheme, which we characterise both the precision and accuracy of by measuring the response of a control feature. We demonstrate that the technique can successfully probe liquid samples and using two spectrally similar types of haemoglobin we show that obtaining a given precision in resolution requires fewer heralded single probe photons compared to using an idealised laser.
Original languageEnglish
Article number023013
Number of pages9
JournalNew Journal of Physics
Volume19
DOIs
Publication statusPublished - 2 Feb 2017

Structured keywords

  • Bristol Quantum Information Institute
  • QETLabs

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