We report detailed studies of the dynamics of monolayer colloid suspensions using two independent... more We report detailed studies of the dynamics of monolayer colloid suspensions using two independent experimental techniques: patterned fluorescence correlation spectroscopy (PFCS) and digital video fluorescence microscopy (DVFM). PFCS is a versatile method that uses sensitive fluorescence detection to measure wavevector-dependent time correlation functions. The systems studied consist of 1 micron charge-stabilized, poly(styrene) spheres in a thin capillary cell ( 1.2
Control of nuclear centration in the C. elegans zygote by receptor-independent Gα signaling and m... more Control of nuclear centration in the C. elegans zygote by receptor-independent Gα signaling and myosin II
Time-dependent spatial distributions of density fluctuations in synthetic and biological systems ... more Time-dependent spatial distributions of density fluctuations in synthetic and biological systems are determined from purely incoherent fluorescence signals. This is accomplished using a new method, Fourier imaging correlation spectroscopy (FICS), that is based on the detection of ...
Rochester Conference on Coherence and Quantum Optics (CQO-11), 2019
We introduce optical lock-in detection in coincidence photon counting to enhance the extraction o... more We introduce optical lock-in detection in coincidence photon counting to enhance the extraction of information in “quantum-light spectroscopy”, based on using time-frequency entangled photon pairs to probe a molecular sample. The sample is placed inside a Mach-Zehnder interferometer, into which photons are injected and detected in coincidence at the interferometer output. Clear signatures of two-photon interference (both ‘Hong-Ou-Mandel’ and ‘N00N’) are observed and separated into distinct information channels. In addition to achieving an increased signal-to-noise ratio (SNR) at low count rates, the experiment uses a “down-sampling” technique that increases the efficiency of data collection by an order of magnitude.
While two-photon absorption (TPA) and other forms of nonlinear interactions of molecules with iso... more While two-photon absorption (TPA) and other forms of nonlinear interactions of molecules with isolated time-frequency-entangled photon pairs (EPP) have been predicted to display a variety of fascinating effects, their potential use in practical quantum-enhanced molecular spectroscopy requires close examination. This paper presents a detailed theoretical study of quantum-enhanced TPA by both photon-number correlations and spectral correlations, including an account of the deleterious effects of dispersion. While such correlations in EPP created by spontaneous parametric down conversion can increase the TPA rate significantly in the regime of extremely low optical flux, we find that for typical molecules in solution this regime corresponds to such low TPA event rates as to be unobservable in practice. Our results support the usefulness of EPP spectroscopy in atomic or other narrow-linewidth systems, while questioning the efficacy of such approaches for broadband systems including mole...
We report detailed studies of the dynamics of monolayer colloid suspensions using two independent... more We report detailed studies of the dynamics of monolayer colloid suspensions using two independent experimental techniques: patterned fluorescence correlation spectroscopy (PFCS) and digital video fluorescence microscopy (DVFM). PFCS is a versatile method that uses sensitive fluorescence detection to measure wavevector-dependent time correlation functions. The systems studied consist of 1 micron charge-stabilized, poly(styrene) spheres in a thin capillary cell ( 1.2
Control of nuclear centration in the C. elegans zygote by receptor-independent Gα signaling and m... more Control of nuclear centration in the C. elegans zygote by receptor-independent Gα signaling and myosin II
Time-dependent spatial distributions of density fluctuations in synthetic and biological systems ... more Time-dependent spatial distributions of density fluctuations in synthetic and biological systems are determined from purely incoherent fluorescence signals. This is accomplished using a new method, Fourier imaging correlation spectroscopy (FICS), that is based on the detection of ...
Rochester Conference on Coherence and Quantum Optics (CQO-11), 2019
We introduce optical lock-in detection in coincidence photon counting to enhance the extraction o... more We introduce optical lock-in detection in coincidence photon counting to enhance the extraction of information in “quantum-light spectroscopy”, based on using time-frequency entangled photon pairs to probe a molecular sample. The sample is placed inside a Mach-Zehnder interferometer, into which photons are injected and detected in coincidence at the interferometer output. Clear signatures of two-photon interference (both ‘Hong-Ou-Mandel’ and ‘N00N’) are observed and separated into distinct information channels. In addition to achieving an increased signal-to-noise ratio (SNR) at low count rates, the experiment uses a “down-sampling” technique that increases the efficiency of data collection by an order of magnitude.
While two-photon absorption (TPA) and other forms of nonlinear interactions of molecules with iso... more While two-photon absorption (TPA) and other forms of nonlinear interactions of molecules with isolated time-frequency-entangled photon pairs (EPP) have been predicted to display a variety of fascinating effects, their potential use in practical quantum-enhanced molecular spectroscopy requires close examination. This paper presents a detailed theoretical study of quantum-enhanced TPA by both photon-number correlations and spectral correlations, including an account of the deleterious effects of dispersion. While such correlations in EPP created by spontaneous parametric down conversion can increase the TPA rate significantly in the regime of extremely low optical flux, we find that for typical molecules in solution this regime corresponds to such low TPA event rates as to be unobservable in practice. Our results support the usefulness of EPP spectroscopy in atomic or other narrow-linewidth systems, while questioning the efficacy of such approaches for broadband systems including mole...
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