Spectroscopic investigations of a [formula omitted] waveguide for photon-echo quantum memory

Abstract

We report the fabrication and characterization of a Ti 4 + : Tm 3 + : LiNbO 3 optical waveguide in view of photon-echo quantum memory applications. Specifically, we investigated room- and cryogenic-temperature properties of the waveguide, and the Tm 3 + ions, via absorption, spectral hole burning, photon echo, and Stark spectroscopy. For the Tm 3 + ions, we found radiative lifetimes of 82 μ s and 2.4 ms for the H 4 3 and F 4 3 levels, respectively, and a 44% branching ratio from the H 4 3 to the F 4 3 level. We also measured an optical coherence time of 1.6 μ s for the H 6 3 ↔ H 4 3 , 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 25 kHz cm / V . Our results are promising for integrated, electro-optical, waveguide quantum memory for photons.