Spectral manipulation of optical pulses using the gradient echo memory scheme

The burgeoning fields of quantum computing and quantum key distribution have created a demand for a quantum memory. The gradient echo memory (GEM) is one such scheme that can boast efficiencies approaching unity. Here we investigate the ability of GEM to spectrally manipulate light pulses stored in the memory. Spectral manipulation is important for pulse compression sideband extraction, and matching of pulse spectra to resonant and spectroscopic systems, as well as the potential to increase qubit rates in quantum communications networks. We present both theoretical and experimental results demonstrating the ability to shift the frequency, as well as spectrally compress or expand a pulse. Also the ability of GEM to recall different frequency components of a pulse at different times, and interfere two initially time separated pulses that are stored in the memory, are shown.