Nanosecond Resolution Observations: Quantum-Optical Spectroscopy and Intensity Interferometry

Muhammed Shafi K., Deepak Pandey, Buti Suryabrahmam +2 more

An accurate measurement of the bunching of photons in the fluorescent emission from an ultracold ensemble of thermal 87Rb atoms in a steady-state magneto-optical trap is presented. Time-delayed-intensity-interferometry (TDII) performed with a 5-nanosecond time resolution yielded a second-order intensity correlation function that has the ideal value of 2 at zero delay, and that shows coherent Rabi oscillations of upto 5 full periods - much longer than the spontaneous emission lifetime of the excited state of Rb. The oscillations are damped out by ~150ns, and thereafter, as expected from a thermal source, an exponential decay is observed, enabling the determination of the temperature of the atomic ensemble. Values so obtained compare well with those determined by standard techniques. TDII thus enables a quantitative study of the coherent and incoherent dynamics, even of a large thermal ensemble of atomic emitters.

Durrani, Ijaz

Juan F. Hodelin

Richard J. Birrittella, Paul M. Alsing, Christopher C. Gerry

In this paper, the authors review the use of parity as a detection observable in quantum metrology and introduce some original findings with regard to measurement resolution in Ramsey spectroscopy and quantum nondemolition measures of atomic parity. Parity was first introduced in the context of Ramsey spectroscopy as an alternative to atomic state detection. It was later adapted for use in quantum optical interferometry where it has been shown to be the optimal detection observable saturating the quantum Cramér–Rao bound for path symmetric states. The authors include a brief review on the basics of phase estimation and the connection between parity-based detection and the quantum Fisher information as it applies to quantum optical interferometry. The authors also discuss the efforts made in experimental methods of measuring photon-number parity and close the paper with a discussion on the use of parity, leading to enhanced measurement resolution in multi-atom spectroscopy. The authors show how this may be of use in the construction of high-precision multi-atom atomic clocks.

K. Muhammed Shafi, Deepak Pandey, Hema Ramachandran

Time-delayed intensity-interferometry employing light emitted by an ensemble of laser-cooled rubidium atoms was used to determine its temperature on timescales of microseconds, and to observe signatures of coherent population oscillations on time scales of nanoseconds.

Florian Kaiser, Panagiotis Vergyris, Djeylan Aktas +3 more