Umakant D. Rapol

Loading of a Rb magneto-optic trap from a getter source

We study the properties of a Rb magneto-optic trap loaded from a commercial getter source. The source provides a large flux of atoms for the trap along with the capability of rapid turn off necessary for obtaining long trap lifetimes. We have studied the trap loading at two different values of background pressure to determine the cross section for Rb-N2 collisions to be 3.5(4)310214 cm2 and that for Rb-Rb collisions to be of order 3310213 cm2. At a background pressure of 1.331029 torr, we load more than 108 atoms into the trap with a time constant of 3.3 s. The 1/e lifetime of trapped atoms is 13 s limited only by background collisions.

High-accuracy wavemeter based on a stabilized diode laser

We have built a high-accuracy wavelength meter for tunable lasers using a scanning Michelson interferometer and a reference laser of known wavelength. The reference laser is a frequency-stabilized diode laser locked to an atomic transition in Rb. The wavemeter has a statistical error per measurement of 5 parts in

Precise measurement of hyperfine intervals using avoided crossing of dressed states

10^7

Subnatural linewidth in room-temperature Rb vapor using a control laser

, which can be reduced considerably by averaging. Using a second stabilized diode laser, we have verified that systematic errors are below 4 parts in

Precise measurements of UV atomic lines: Hyperfine structure and isotope shifts in the 398.8 nm line of Yb

10^8

Precise measurement of hyperfine structure in the state of Rb

.

Frequency locking of tunable diode lasers to a rubidium-stabilized ring-cavity resonator

We demonstrate a technique for precisely measuring hyperfine intervals in alkali atoms. The atoms form a three-level Λ system in the presence of a strong control laser and a weak probe laser. The dressed states created by the control laser show significant linewidth reduction. We have developed a technique for Doppler-free spectroscopy that enables the separation between the dressed states to be measured with high accuracy even in room temperature atoms. The states go through an avoided crossing as the detuning of the control laser is changed from positive to negative. By studying the separation as a function of detuning, the center of the level-crossing diagram is determined with high precision, which yields the hyperfine interval. Using room temperature Rb vapor, we obtain a precision of 44 kHz. This is a significant improvement over the current precision of ~ 1 MHz.

Laser cooling and trapping of Yb from a thermal source

We demonstrate two ways of obtaining subnatural linewidth for probe absorption through room-temperature Rb vapor. Both techniques use a control laser that drives the transition from a different ground state. The coherent drive splits the excited state into two dressed states (Autler-Townes doublet), which have asymmetric linewidths when the control laser is detuned from resonance. In the first technique, the laser has a large detuning of 1.18 GHz to reduce the linewidth to 5.1 MHz from the Doppler width of 560 MHz. In the second technique, we use a counterpropagating pump beam to eliminate the first-order Doppler effect. The unperturbed probe linewidth is about 13 MHz, which is reduced below 3 MHz

Doppler-free spectroscopy in driven three-level systems

(0.5\ensuremath{\Gamma})

Precise measurement of hyperfine structure in the 5P3/2 state of 85Rb

at a detuning of 11.5 MHz.