Periodically poled KTP based High Efficiency Second Harmonic Generation of Cesium D2 line for Atomic Quantum Memory experiments

Summary form only given. One of the major objectives in the field of quantum information is the realization of a memory for the quantum states of the light. The squeezed vacuum is required in order to test the quantum character of the memory i.e. its capability to store informations that rely on the quantum nature of the light. In order to generate the squeezed vacuum at a wavelength that is resonant with the elected atomic transition, we adopt an experimental configuration that consists in a continuous wave subthreshold frequency degenerate optical parametric oscillator (OPO) pumped by a frequency doubled Ti:Sa laser. we achieve more than 300 mW stable blue-light at 426 nm; that is, to the best of our knowledge, the highest power obtained to date at this wavelength.