Rare-Earth-Doped Y₂SiO₅ Crystal Directly Bonded on Glass for Efficient Optical Quantum Technologies Platform

For high-efficiency optical quantum technology platforms, bonding rare-earth doped crystals on glass are of great interest, enabling the enhancement of the optical guided mode interaction with the active rare-earth ions. Optical coherence lifetimes and stable operation are operated at very low temperature (3-4 K). Bonding should be preferably performed without adding any intermediate sticking layer in order not to hamper the optical mode distribution and propagation. Directly bonded Y2SiO5 crystal on a borosilicate glass is shown and the bonding mechanisms are discussed.