Mariusz Semczuk

High-resolution photoassociation spectroscopy of the Li-6(2) A(1(1)Sigma(+)(u)) state

We present spectroscopic measurements of seven vibrational levels nu = 29-35 of the A(1(1)Sigma(+)(u)) excited state of Li-2 molecules by the photoassociation of a degenerate Fermi gas of Li-6 atoms. The absolute uncertainty of our measurements is +/- 0.000 02 cm(-1) (+/- 600 kHz) and we use these new data to further refine an analytic potential for this state. This work provides high accuracy photoassociation resonance locations essential for the eventual high-resolution mapping of the X(1(1)Sigma(+)(g)) state enabling further improvements to the s-wave scattering length determination of Li and enabling the eventual creation of ultracold ground- state Li-6(2) molecules.

An adaptable dual species effusive source and Zeeman slower design demonstrated with Rb and Li

We present a dual-species effusive source and Zeeman slower designed to produce slow atomic beams of two elements with a large mass difference and with very different oven temperature requirements. We demonstrate this design for the case of (6)Li and (85)Rb and achieve magneto-optical trap (MOT) loading rates equivalent to that reported in prior work on dual species (Rb+Li) Zeeman slowers operating at the same oven temperatures. Key design choices, including thermally separating the effusive sources and using a segmented coil design to enable computer control of the magnetic field profile, ensure that the apparatus can be easily modified to slow other atomic species. By performing the final slowing using the quadrupole magnetic field of the MOT, we are able to shorten our Zeeman slower length making for a more compact system without compromising performance. We outline the construction and analyze the emission properties of our effusive sources. We also verify the performance of the source and slower, and we observe sequential loading rates of 12 × 10(8) atoms/s for a Rb oven temperature of 140 °C and 1.1 × 10(8) atoms/s for a Li reservoir at 460 °C, corresponding to reservoir lifetimes for continuous operation of 10 and 4 years, respectively.

Method for independent and continuous tuning of N lasers phase-locked to the same frequency comb.

We present a method of phase locking any number of continuous-wave lasers to an optical frequency comb (OFC) that enables independent frequency positioning and control of each laser while still maintaining lock to the OFC. The scheme employs an acousto-optic modulator (AOM) in a double-pass configuration added to each laser before its light is compared by optical heterodyne with the comb. The only requirement is that the tuning bandwidth of the double-pass AOM setup be larger than half the OFC repetition rate. We demonstrate this scheme and achieve an arbitrary frequency tuning precision, a tuning rate of 200 MHz/s, and a readout precision at the 1 kHz level.

Realization of BEC-BCS crossover physics in a compact oven-loaded magneto-optic trap apparatus

Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada(Dated: August 19, 2013)We report on a simple oven-loaded magneto-optical trap (MOT) apparatus for the creation ofboth molecular Bose-Einstein condensates (mBEC) and degenerate Fermi gases (DFGs) of lithium.The apparatus does not require a Zeeman slower or a 2D MOT nor does it require any separationor di erential pumping between the e usive atom source and the science chamber. The result is anexceedingly simple, inexpensive, and compact vacuum system ideal for miniaturization. We discussour work in the context of other realizations of quantum degenerate gases by evaporation in opticaldipole traps and illustrate that our apparatus meets the key requirements of atom number and traplifetime. With this system, we also demonstrate the production of a mBEC, and we use it to observethe pairing gap of a strongly interacting two-component DFG in the BEC-BCS crossover regime.

Cavity ring down spectroscopy experiment for an advanced undergraduate laboratory

A simple experiment is described that permits advanced undergraduates to learn the principles and applications of the cavity ring down spectroscopy technique. The apparatus is used for measurements of low concentrations of NO2 produced in air by an electric discharge. We present the setup, experimental procedure, data analysis and some typical results.

Transparent electrodes for high E-field production using a buried indium tin oxide layer

We present a design and characterization of optically transparent electrodes suitable for atomic and molecular physics experiments where high optical access is required. The electrodes can be operated in air at standard atmospheric pressure and do not suffer electrical breakdown even for electric fields far exceeding the dielectric breakdown of air. This is achieved by putting an indium tin oxide coated dielectric substrate inside a stack of dielectric substrates, which prevents ion avalanche resulting from Townsend discharge. With this design, we observe no arcing for fields of up to 120 kV/cm. Using these plates, we directly verify the production of electric fields up to 18 kV/cm inside a quartz vacuum cell by a spectroscopic measurement of the dc Stark shift of the 5(2)S(1/2) → 5(2)P(3/2) transition for a cloud of laser cooled rubidium atoms. We also report on the shielding of the electric field and on the residual electric fields that persist within the vacuum cell once the electrodes are discharged. In addition, we discuss observed atom loss that results from the motion of free charges within the vacuum. The observed asymmetry of these phenomena on the bias of the electrodes suggests that field emission of electrons within the vacuum is primarily responsible for these effects and may indicate a way of mitigating them.

Giant Feshbach resonances in {sup 6}Li-{sup 85}Rb mixtures

We report on the observation of six large Feshbach resonances in a Fermi-Bose mixture of

Giant Feshbach resonances in Li 6 - Rb 85 mixtures

^{6}\mathrm{Li}

High-resolution photoassociation spectroscopy of the6Li2A(11Σu+)state

and

Anomalous behavior of dark states in quantum gases of (6)Li.

^{85}\mathrm{Rb}