Measuring protein concentration with entangled photons

Andrea Crespi, Mirko Lobino, Jonathan C.F. Matthews, Alberto Politi, Chris R. Neal, Roberta Ramponi, Roberto Osellame, Jeremy L. O'Brien

Research output: Contribution to journalArticlepeer-review

111 Citations (Scopus)
33 Downloads (Pure)


Optical interferometry is amongst the most sensitive techniques for precision measurement. By increasing the light intensity, a more precise measurement can usually be made. However, if the sample is light sensitive entangled states can achieve the same precision with less exposure. This concept has been demonstrated in measurements of known optical components. Here, we use two-photon entangled states to measure the concentration of a blood protein in an aqueous buffer solution. We use an opto-fluidic device that couples a waveguide interferometer with a microfluidic channel. These results point the way to practical applications of quantum metrology to light-sensitive samples.

Original languageEnglish
Article number233704
JournalApplied Physics Letters
Issue number23
Publication statusPublished - 4 Jun 2012
Externally publishedYes


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