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arXiv · 1508.00849

Quantum-enhanced absorption spectroscopy

Rebecca Whittaker·Chris Erven·Alex Neville·Monica Berry·Jeremy L. O'Brien·Hugo Cable·Jonathan C. F. Matthews
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Abstract

Absorption spectroscopy is routinely used to characterise chemical and biological samples. For the state-of-the-art in 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 sub-shot-noise absorption spectroscopy. We measure the absorption spectra of spectrally-similar biological samples---oxyhaemoglobin and carboxyhaemoglobin---and show that obtaining a given precision in resolution requires fewer heralded single probe photons compared to using an ideal laser.

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Rebecca Whittaker, Chris Erven, Alex Neville, Monica Berry, Jeremy L. O'Brien, Hugo Cable, Jonathan C. F. Matthews. 2015-08-04. Quantum-enhanced absorption spectroscopy. https://doi.org/10.1088/1367-2630%2Faa5512

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