Efficient microwave-to-optical conversion using Rydberg atoms

We demonstrate microwave-to-optical conversion using six-wave mixing in $^{87}$Rb atoms where the microwave field couples to two atomic Rydberg states, and propagates collinearly with the converted optical field. We achieve a photon conversion efficiency of ~5% in the linear regime of the converter. In addition, we theoretically investigate all-resonant six-wave mixing and outline a realistic experimental scheme for reaching efficiencies greater than 60%

Probing the dynamics of an optically trapped particle by phase sensitive back focal plane interferometry

The dynamics of an optically trapped particle are often determined by measuring intensity shifts of the back-scattered light from the particle using position sensitive detectors. We present a technique which measures the phase of the back-scattered light using balanced detection in an external Mach-Zender interferometer scheme where we separate out and beat the scattered light from the bead and that from the top surface of our trapping chamber. The technique has improved axial motion resolution over intensity-based detection, and can also be used to measure lateral motion of the trapped particle. In addition, we are able to track the Brownian motion of trapped 1 and 3 $\mu$m diameter beads from the phase jitter and show that, similar to intensity-based measurements, phase measurements can also be used to simultaneously determine displacements of the trapped bead as well as the spring constant of the trap. For lateral displacements, we have matched our experimental results with a simulation of the overall phase contour of the back-scattered light for lateral displacements by using plane wave decomposition in conjunction with Mie scattering theory. The position resolution is limited by path drifts of the interferometer which we have presently reduced to obtain a displacement resolution of around 2 nm for 1.1 $\mu$m diameter probes by locking the interferometer to a frequency stabilized diode laser.Comment: 10 pages, 7 figure

MOLECULAR SPECTROSCOPY OF ULTRACOLD 6LITHIUM ¿¿40 POTASSIUM MOLECULES: TOWARDS STIRAP TRANSFER TO ABSOLUTE GROUND STATE

Ph.DDOCTOR OF PHILOSOPH

Magnetic trapping of Yb in the metastable P-3(2) state

We report magnetic trapping of Yb in the excited P-3(2) state. This state, with a lifetime of 15 s, could play an important role in studies ranging from optical clocks and quantum computation to the search for a permanent electric dipole moment. Yb atoms are first cooled and trapped in the ground state in a 399-nm magneto-optic trap. The cold atoms are then pumped into the excited state by driving the S-1(0) -> P-3(1) -> S-3(1) transition. Atoms in the P-3(2) state are magnetically trapped in a spherical quadrupole field with an axial gradient of 110 G/cm. We trap up to 10(6) atoms with a lifetime of 1.5 s