Research

Quantum Information

Heralded single photons with the longest temporal width in the world (2022/5/27)

We generated the biphotons with a temporal full width at half maximum (FWHM) of 13.4 ms and a spectral FWHM of 50 kHz, employing cold atoms. The temporal width is the longest, and the spectral linewidth is the narrowest up to date. This is the first biphoton result that obtains a linewidth below 100 kHz, reaching a new milestone.

A room-temperature source of heralded single photons with the highest spectral brightness in the world (2021/8/12)

Utilizing a 65 °C atomic vapor, we produced the biphotons with a linewidth of 960 kHz and a generation rate of 3.7´105 pairs/s. The large generation rate, together with the narrow linewidth, results in a high spectral brightness of 3.8´105 pairs/s/MHz, which is the best result to date.

Quantum Optics

Storage and retrieval of light pulses

Bose-Einstein Condensation

Experimental demonstraion of ⁸⁷Rb BEC (AM 01:42 at May 17, 2006)

Laser Cooling

Free falling of laser-cooled atoms

The image of the free-falling trapped atoms at 10^-5K, where different colors corespond to different atomic density. The signal above is the image taken at t = 0.01s, while the one below is at 0.03s. The actual scale of image is calibrated by the displacement of the free falling atoms within a given time, and the expansion of the atoms is measured to estimate its temperature.

Atoms in the magneto-optical trap

In this movie, trapped atoms follow the zero of the quadrupole magnetic field which is affected by a magnet outside the trapping cell.