Optical coherence correlation spectroscopy (OCCS)

Abstract

We present a new method called optical coherence correlation spectroscopy (OCCS) using nanoparticles as reporters of kinetic processes at the single particle level. OCCS is a spectral interferometry based method, thus giving simultaneous access to several sampling volumes along the optical axis. Based on an auto-correlation analysis, we extract the diffusion coefficients and concentrations of nanoparticles over a large concentration range. The cross-correlation analysis between adjacent sampling volumes allows to measure flow parameters. This shows the potential of OCCS for spatially resolved diffusion and flow measurements.

3D Time-lapse Imaging and Quantification of Mitochondrial Dynamics

“…All instrument parameters, r 0 and z 0 , were evaluated by measuring the point spread function (PSF), fitting it with a Gaussian profile, ( Fig. S5 ) and by taking into account the coherence length which defines the axial extent of the PSF 28 29 . For a more in depth discussion of coherent correlation analysis please refer to previous papers in OCCS 28 29 .…”

“…S5 ) and by taking into account the coherence length which defines the axial extent of the PSF 28 29 . For a more in depth discussion of coherent correlation analysis please refer to previous papers in OCCS 28 29 . Due to the interferometric detection, our signal has extremely high sensitivity to phase and not only intensity in contrast to ICS of Wiseman and Petersen.…”

Microscale imaging of cilia-driven fluid flow

“…If the signal originates from the backscattered light of particles in optical coherence tomography (OCT), then the analysis is known as dynamic light scattering (DLS)-OCT [58,59]. Decorrelation-based OCT approaches have been applied towards imaging fluid speed and diffusion [60–62]. …”

Label‐Free Fluctuation Spectroscopy Based on Coherent Anti‐Stokes Raman Scattering from Bulk Water Molecules

“…Moreover, in contrast to our approach, DLS cannot determine particle concentrations, cannot be easily combined with fluorescence readouts, and does not lend itself to detection in highly confined detection volumes with subsequent imaging/scanning capabilities. Correlation spectroscopies with confined detection volumes, with readouts that can replace the fluorescence signal used in FCS, have also been successfully demonstrated, based on surface‐enhanced resonance Raman scattering (SERRS), resonance light scattering, nonlinear light scattering, plasmon luminescence, coherent anti‐Stokes Raman scattering (CARS),photothermal interferometric, and other interferometric readouts . Some of these readouts can also be considered to be label free.…”

“…In FCS, the fluorescence brightness of the individual molecules/particles studied is a key figure of merit . Likewise, the signal per particle/molecule of these other read‐out modalities needs to be in parity with the fluorescence signal they replace. This requirement regarding molecular/particle brightness restricts the range of molecules/particles that can be studied with these spectroscopic approaches.…”