Optical storage and retrieval of arbitrary pulse shapes

As quantum information science advances, the storage and accurate retrieval of quantum states as light pulses will be vital for viable quantum ‘memory'. With the pursuit of quantum storage in mind, in this paper we expand the analysis done previously on storing Gaussian light pulses to undefined pulse shapes and derive a generalized expression for the retrieved light pulse from electromagnetically induced transparency (EIT) storage in a three-level Λ system. Starting from the coupled differential equations that govern the retrieval of the stored pulse, we derive a formula using parameters of the control pulses and the atomic system that can be used with any arbitrary pulse shape to be stored. We also examine the role of a modified reading pulse for increasing the fidelity of the retrieval process. We compare the results of our formula to explicitly calculated results for the Gaussian pulse, then calculate results using our formula for other probe pulse shapes, including double-Gaussian and super Gaussian pulses. The study will be extended to further explore storage and retrieval of quantum information.