Jai Hyung Lee

Observation of sub-poisson photon statistics in the cavity-QED microlaser.

We have measured the second-order correlation function of the cavity-QED microlaser output and observed a transition from photon bunching to antibunching with increasing average number of intracavity atoms. The observed correlation times and the transition from super- to sub-Poisson photon statistics can be well described by gain-loss feedback or enhanced-reduced restoring action against fluctuations in photon number in the context of a quantum microlaser theory and a photon rate equation picture. However, the theory predicts a degree of antibunching several times larger than that observed, which may indicate the inadequacy of its treatment of atomic velocity distributions.

Spectral line-shape measurement of an extremely weak amplitude-fluctuating light source by photon-counting-based second-order correlation spectroscopy

We demonstrate line-shape measurement of an extremely weak amplitude-fluctuating light source by using photon-counting-based second-order correlation spectroscopy combined with the heterodyne technique. The amplitude fluctuation of a finite bandwidth introduces a low-lying spectral structure in the line shape, and thus its effect can be isolated from that of the phase fluctuation. Our technique provides extreme sensitivity suited for single-atom-level applications.

Self-induced transparency in samarium atomic vapor under condition of high temperature and high density

We performed the experiment of self-induced transparency in samarium atomic vapor under the condition of high temperature and high density. The sudden onset of the transmission, the maximum pulse delay and the pulse broadening were observed with π pulse. With this result we estimate the dipole moment of the transition line for 152Sm. The peak amplification, the pulse narrowing and the pulse breakup were observed when the pulse area was above 3π. These observations are strong evidences of self-induced transparency. Our result is the observation of self-induced transparency under the highest-temperature, highest-density condition and the first observation of this phenomenon in samarium vapor to our knowledge.

Calibration of second-order correlation functions for nonstationary sources with a multistart, multistop time-to-digital converter

A novel high-throughput second-order correlation measurement system is developed that records and makes use of all the arrival times of photons detected at both start and stop detectors. This system is suitable, particularly for a light source having a high photon flux and a long coherence time, since it is more efficient than conventional methods by an amount equal to the product of the count rate and the correlation time of the light source. We have used this system in carefully investigating the dead time effects of detectors and photon counters on the second-order correlation function in the two-detector configuration. For a nonstationary light source, a distortion of the original signal was observed at high photon flux. A systematic way of calibrating the second-order correlation function has been devised by introducing the concept of an effective dead time of the entire measurement system.

Generation of vortex by light-induced phase mask in a V-type atomic system

Optical vortices on a weak probe beam were generated by a strong pump beam with a vortex array or an L-shape stripe. We also observed a pair of vortices having opposite charges with the total charges conserved.

Spectrum Measurement Of The Cavity-QED Microlaser: Deviation From The Schawlow-Townes Linewidth

We report the measurement of the cavity-QED microlaser linewidth near threshold by using the photon-counting-based second-order correlation spectroscopy. The abrupt rise-and-fall of the linewidth near thereshold is observed.

Effects of Bipolar Atom-Cavity Coupling in the Cavity-QED Microlaser

We demonstrated that the TEM10 mode of the cavity-QED microlaser shows the split-resonance lineshape. It is explained by the bipolar atom-cavity coupling that the two-level excited atoms experience while they transverse the cavity mode.

Elimination of self-focusing and self-defocusing under the condition of electromagnetically induced transparency in a lambda-type atomic samarium vapor

We observed that the spatial distortions of a probe pulse from Kerr nonlinearity were eliminated almost perfectly when a strong coupling pulse copropagates with the probe on two-photon-resonance in /spl Lambda/-type 3 levels of atomic Sm.

DYNAMIC BEHAVIOR IN THE ANGULAR DISTRIBUTION OF EMISSION FROM A MICROMETER-SIZED ASYMMETRIC LIQUID JET

The dynamic behavior in the angular distribution of emission was measured from an asymmetrically distorted liquid jet which was induced by laterally flowing gas. We observed that the intensity pattern was restricted to around ~90°, above 2% of the distortion parameter η. The fine structure of the intensity pattern was also restricted to ~90°, which is evidence of the directional emission of MDR (morphology-dependent resonance) lights. As η increases, the intensity profile narrows down to ~90° and then broadens at η≥5%. We found that a broad peak shifts continuously with a linear relationship to η, which should be related to the detailed shape of deformation. Broad split peaks were observed when the intensity of emission was substantially enhanced for efficient coupling, which is not expected from the ray-optics model for an ideal elliptical microcavity.