Spectroscopic investigations of a image waveguide for photon-echo quantum memory

We report the fabrication and characterization of a image optical waveguide in view of photon-echo quantum memory applications. Specifically, we investigated room- and cryogenic-temperature properties of the waveguide, and the image ions, via absorption, spectral hole burning, photon echo, and Stark spectroscopy. For the image ions, we found radiative lifetimes of image and 2.4 ms for the image and image levels, respectively, and a 44% branching ratio from the image to the image level. We also measured an optical coherence time of image for the image, 795 nm wavelength transition, and investigated the limitation of spectral diffusion to spectral hole burning. Upon application of magnetic fields of a few hundred Gauss, we observed persistent spectral holes with lifetimes up to seconds. Furthermore, we measured a linear Stark shift of image. Our results are promising for integrated, electro-optical, waveguide quantum memory for photons.