Glass Thin Films for Planar Optical Components Fabricated using Ultrafast Laser Plasma Doping

Ultrafast pulsed lasers with pulse durations of 40-100 fs are used to deposit rare earth doped tellurite glass onto silica glass substrates in a pulsed laser deposition (PLD) chamber. Under certain conditions, the tellurite glass plasma mixes with the silica glass network producing a thin glass film of tellurite-modified-silica which produces some unique physical, and when doped with rare earth ions, spectroscopic properties. Layers of tellurite-modified-silica glass up to 2 µm thick have been produced with refractive indices of around 1.65, compared to 1.46 and 2.0 for the silica substrate and tellurite target glasses, respectively. Rare earth ions can be doped into these layers in concentrations which are higher than would be possible in pure silica glass without clustering, and Er³⁺ for example exhibits unusually long 1.535 µm fluorescence lifetimes in these thin films. Tm³⁺ ions have also been doped into these layers, yielding fluorescence with wavelength up to around 2 µm.