Harnessing Quantum Light for Enhanced Sensing of Biokinetic Processes*

Biokinetic processes are attributes used to characterize how systems interact on a molecular level which can be used for biomedical applications such as drug synthesis. One method to measure these processes is using a plasmonic sensor; the precision of which depends on the number of photons used in the study. Plasmonic sensors use photon-phonon interactions to extract information, and as such the shot noise limit (SNL) of the number of photons imposes a limit on the minimum amount of information that can be extracted. All classical light sources have some fundamental uncertainties in the number of photons they produce which sets the best measurement performance bounded by the SNL. By using the four-wave mixing (FWM) process, one can create two quantum entangled beams of light which have a quantum correlated number of photons for any given moment in time. Using these two quantum correlated beams of light, the SNL can be overcome thus improving the precision of the measurement. In this study, we report a quantum-enhanced sub-SNL measurement of the biokinetic process of bovine serum albumin (BSA) and demonstrate the quantum advantage of using entangled beams of light for biomedical applications.