Few-photon heterodyne spectroscopy.

Low-coherence heterodyne photon correlation spectroscopy.

Photon correlation spectroscopy (PCS) is routinely used to investigate the dynamics of colloidal particles undergoing Brownian motion. This technique is applicable to low-density colloidal suspensions in which the effects of multiple light scattering are minimal. We introduce a new low-coherence heterodyne PCS technique that allows direct investigation of colloidal suspensions of higher concent...

Photon Counting for Bragg Spectroscopy of Quantum Gases

We demonstrate a photon-counting technique for detecting Bragg excitation of an ultracold gas of atoms. By measuring the response of the light field to the atoms, we derive a signal independent of traditional time-of-flight atom-imaging techniques. With heterodyne detection we achieve photon shot-noise limited detection of the amplification or depletion of one of the Bragg laser beams. Photon c...

High-Concentration Submicron Particle Size Distribution by Dynamic Light Scattering: Power spectrum development with heterodyne technology advances biotechnology and nanotechnology measurements

Homodyne and heterodyne X-ray photon correlation spectroscopy: latex particles and elastomers

In a coherent X-ray small-angle experiment, heterodyning between the scattering amplitudes of two samples is obtained by stacking a static reference and a fluctuating sample. Results of homodyne and heterodyne measurements are compared in the case of 98 nm diameter latex particles in glycerol. The method is also used for the study of the slow relaxation process of carbon-blackfilled ethylene–pr...

Two-Dimensional Optical Heterodyne Spectroscopy of Molecular Complexes

Optical heterodyne two-dimensional (2D) photon echoes from room-temperature BIC J-aggregates were recorded. Analysis of the time-dependent 2D spectrum reveals the frequency dependence of the exciton relaxation, and discriminates diagonal and offdiagonal exciton phonon coupling. Frequency-dependent dynamics is expected to be ubiquitous in systems with band structures. Quantum dynamical models of...