Coherence Observation by Interference Noise

Ilya Sh. Averbukh, Opher Kinrot, Yehiam Prior

Yehiam Prior, Ilya Sh. Averbukh, Opher Kinrot

We present a novel approach — Coherence Observation by Interference Noise (COIN) — for the measurement of coherence. The method is based on analysis of the quantum interference fluctuations (noise) in the incoherent emission from a medium, following the excitation by a pair of time delayed pulses with random relative phase. In addition to spectroscopic applications, the new method is useful for the characterization of short pulses and their wavelength determination.

Z. Ficek, S. Swain, William T. Rhodes +9 more

Opher Kinrot, Ilya Sh. Averbukh, Yehiam Prior

We present a new approach to the measurement of coherence. By monitoring the quantum interference fluctuations in the population excited by a pair of time-delayed, randomly phased pulses, it is possible to extract information on internal dynamics, energy level splittings, and characteristic coherence decay times of the medium. As a proof of concept, we demonstrate the measurement of phase relaxation and doublet separation in atomic potassium. The principle of coherence observation by interference noise is very general, is shown to be robust and with inherent time resolution of a few optical cycles, and is proposed as an alternative to many interferometric applications.

M. W. Hamilton

Interference fringes can result from the measurement of four-time fourth-order correlation functions of a wave field. These fringes have a statistical origin and, as a consequence, they show the greatest contrast when the coherence time of the field is finite. A simple acoustic experiment is presented in which these fringes are observed, and it is demonstrated that the contrast is maximal for partial coherence. Random telegraph phase noise is used to vary the field coherence in order to highlight the problem of interpreting this interference; for this noise, the Gaussian moment theorem may not be invoked to reduce the description of the interference to one in terms of first-order interference.