Narrow band volume Bragg gratings with enhanced side-lobe suppression for quantum optics

Narrowband spectral filters, based on volume Bragg gratings (VBGs) in photo-thermo-refractive glass, were recently deployed in a wide variety of applications. This material allows recording of VBGs in the visible and near IR spectral regions with high efficiency, narrow bandwidth, high suppression, and large dispersion. Recent advances in VBG technology enabled fabrication of various holographic components well suited for quantum optics applications such as single photon detection, atomic clocks, quantum computing and networks. VBG-based diffractive elements are used for beam combining, signal separation, pump suppression, and as dispersive elements. In this paper we demonstrate manufacturing of high efficiency (>90%) reflecting VBG filters with enhanced suppression of side bands. Such elements provide suppression of background or pump by more than 25 dB for all spectral components shifted from the signal by 70 GHz or higher.