Brian P. Timmons

Light pulse atom interferometry at short interrogation times

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, February 2012.

Efficient broadband Raman pulses for large-area atom interferometry

We report a demonstration of composite Raman pulses that achieve broadband population inversion and are used to increase the momentum splitting of an atom interferometer up to 18ℏk (corresponding to an increase in the inertial signal by a factor of nine). Composite Raman pulses suppress the effects of pulse length and detuning errors, providing higher transfer efficiency and velocity acceptance than single square pulses. We implement two composite pulse sequences, π/20°−π90°−π/20° and π/20°−π180°−3π/20°, and use the latter composite pulse to demonstrate large-area atom interferometry with stimulated Raman transitions. In addition to enabling larger momentum transfer and higher sensitivity, we argue that composite pulses can improve the robustness of atom interferometers operating in dynamic environments.

Atom interferometry via Raman chirped adiabatic passage

Practical atom interferometric sensors may benefit from robust atom optics based on Raman chirped adiabatic passage (RCAP). We demonstrate coherent transfer and interference using RCAP, and discuss expected enhancement of interferometer stability.

Radiation Exposure of Distributed-Feedback Lasers for Use in Atom Trapping and Atom Interferometry

Semiconductor DFB lasers are compact, efficient, robust light sources suitable for use in laser trapping and cooling and for atom interferometry using alkali atoms. Two commercially available DFB lasers (LD-0852-0150-DFB, Eagleyard Photonics) emitting at 852 nm were subjected to gamma and flash x-ray (FXR) radiation, to a total dose of 200 krad (in two exposures) and a prompt dose of 1.2 krad per shot, respectively. We measured frequency shifts and output power before, during and after exposures with the lasers tuned to the Cs D2 resonance. Radiation induced frequency excursions were smaller than the Doppler broadened linewidth. Radiation induced output power losses were negligible in flash x-ray and 1.8 dB after each of the two 100 krad gamma exposures. These results demonstrate that spectroscopy-grade DFB lasers can survive and function in very adverse radiation environments, making possible the radiation-hard implementation of cold atom based clocks and atom interferometer inertial sensors.