arXiv subjects

A. L. Alexander

Publications and source records attributed to A. L. Alexander.

3 recordsLinked to original sources

arXiv2008

Stimulated Raman Adiabatic Passage in Tm$^{3+}$:YAG

We report on the experimental demonstration of stimulated Raman adiabatic passage (STIRAP) in a Tm$^{3+}$:YAG crystal. Tm$^{3+}$:YAG is a promising material for use in quantum information processing applications, but as yet there are few experimental investigations of coherent Raman processes in this material. We investigate the effect of inhomogeneous broadening and Rabi frequency on the transfer efficiency and the width of the two-photon spectrum. Simulations of the complete Tm$^{3+}$:YAG system are presented along with the corresponding experimental results.

quant-ph↗

arXiv2007

Gradient Echo Quantum Memory for Light using Two-level Atoms

We propose a quantum memory for light that is analogous to the NMR gradient echo. Our proposal is ideally perfectly efficient and provides simplifications to current 3-level quantum memory schemes based on controlled inhomogeneous broadening. Our scheme does not require auxiliary light fields. Instead the input optical pulse interacts only with two-level atoms that have linearly increasing Stark shifts. By simply reversing the sign of the atomic Stark shifts, the pulse is retrieved in the forward direction. We present analytical, numerical and experimental results of this scheme. We report experimental efficiencies of up to 15% and suggest simple realizable improvements to significantly increase the efficiency.

quant-ph↗

arXiv2005

Photon Echoes Produced by Switching Electric Fields

We demonstrate photon echoes in Eu$^{3+}$:Y$_{2}$SiO$_{5}$ by controlling the inhomogeneous broadening of the Eu$^{3+}$ $^{7}$F$_{0}\leftrightarrow^{5}$D$_{0}$ optical transition. This transition has a linear Stark shift and we induce inhomogeneous broadening by applying an external electric field gradient. After optical excitation, reversing the polarity of the field rephases the ensemble, resulting in a photon echo. This is the first demonstration of such a photon echo and its application as a quantum memory is discussed.

quant-ph↗