Point and shoot microvibrometry for biological applications

The capabilities of an experimental setup combining the functions of a conventional microscope with a custom built self-mixing interferometer to characterize the contractile motion of living cells in both the transversal and longitudinal directions were explored. The use of discrete wavelets to denoise experimental signals combined with the application of a Hampel filter was shown to outperform standard denoising methods found in the self-mixing literature. Furthermore, an efficient iterative method to reliably estimate the optical feedback level and the linewidth enhancement factor was developed. Experimental displacements of microspheres, used as phantoms for living cells, were reconstructed with a resolution better than 0.15 lambda using the proposed reconstruction method. These results substantiate the claim that the proposed reconstruction method will enable the measurement of the contractile motion of individual cardiomyocytes with a resolution approaching 100 nm

Quantum-enhanced absorption spectroscopy with bright squeezed frequency combs

Absorption spectroscopy is a widely used technique that permits the detection and characterization of gas species at low concentrations. We propose a sensing strategy combining the advantages of frequency modulation spectroscopy with the reduced noise properties accessible by squeezing the probe state. A homodyne detection scheme allows the simultaneous measurement of the absorption at multiple frequencies and is insensitive to dispersion across the absorption profile. We predict a significant enhancement of the signal-to-noise ratio that scales exponentially with the squeezing factor. An order of magnitude improvement beyond the standard quantum limit is possible with state-of-the-art squeezing levels facilitating high precision gas sensing.Comment: 7 pages, 3 figure

Estimating the concentration of chiral media with bright squeezed light

The concentration of a chiral solution is a key parameter in many scientific fields and industrial processes. This parameter can be estimated to high precision by exploiting circular birefringence or circular dichroism present in optically active media. Using the Quantum Fisher information formalism, we quantify the performance of Gaussian probes in estimating the concentration of chiral analytes. We find that bright-polarization squeezed state probes provide a quantum advantage over equally bright classical strategies that scales exponentially with the squeezing factor for a circularly birefringent sample. Four-fold precision enhancement is achievable using state-of-the-art squeezing levels and intensity measurements.Comment: 6 pages, 2 figures, revised text and supplementary material

Point and shoot microvibrometry for biological applications

The capabilities of an experimental setup combining the functions of a conventional microscope with a custom built self-mixing interferometer to characterize the contractile motion of living cells in both the transversal and longitudinal directions were explored. The use of discrete wavelets to denoise experimental signals combined with the application of a Hampel filter was shown to outperform standard denoising methods found in the self-mixing literature. Furthermore, an efficient iterative method to reliably estimate the optical feedback level and the linewidth enhancement factor was developed. Experimental displacements of microspheres, used as phantoms for living cells, were reconstructed with a resolution better than 0.15 lambda using the proposed reconstruction method. These results substantiate the claim that the proposed reconstruction method will enable the measurement of the contractile motion of individual cardiomyocytes with a resolution approaching 100 nm

The advantage of coherent states in ring resonators over any quantum probe single-pass absorption estimation strategy

Quantum states of light have been shown to enhance precision in absorption estimation over classical strategies. By exploiting interference and resonant enhancement effects, we show that coherent-state probes in all-pass ring resonators can outperform any quantum probe single-pass strategy even when normalized by the mean input photon number. We also find that under optimal conditions coherent-state probes equal the performance of arbitrarily bright pure single-mode squeezed probes in all-pass ring resonators.Comment: 7 pages, 4 figures, typos corrected, expanded section 3 and conclusio

Coherent states in ring resonators outperform any quantum probe single-pass absorption estimation strategy

By leveraging interference and resonance enhancement effects, we find all-pass ring resonators with coherent-state probes can estimate absorption more precisely than any quantum probe single-pass strategy, including those using squeezed or Fock states

Quantum-limited absorption estimation with ring resonators

Coherent-state probes in appropriately designed all-pass ring resonators outperform any quantum probe single-pass absorption estimation strategy, including those using Fock or bright squeezed states

Advantage of coherent states in ring resonators over any quantum probe single-pass absorption estimation strategy

Quantum states of light have been shown to enhance precision in absorption estimation over classical strategies. By exploiting interference and resonant enhancement effects, we show that coherent-state probes in all-pass ring resonators can outperform any quantum probe single-pass strategy even when normalized by the mean input photon number. We also find that under optimal conditions coherent-state probes equal the performance of arbitrarily bright pure single-mode squeezed probes in all-pass ring resonators