  We report the formation of arbitrary photoconductive patterns made of
tellurium (Te) nanocrystals by exposing a tellurite (TeO2-based) glass to
femtosecond laser pulses. During this process, Te/TeO2-glass nanocomposite
interfaces with photoconductive properties form on the tellurite glass
substrate. We show that these laser-written patterns have a highly reproducible
photo-response, from the near ultraviolet (263 nm) to the visible spectrum,
stable over a few months. Specifically, high responsivity (16.55 A/W) and
detectivity (5.25*10^11 Jones) of a single laser-written line pattern are
measured for an illumination dose of 0.07 mW/cm^2 at 400 nm. This work
illustrates a pathway for locally turning a tellurite glass into functional
photoconductor of arbitrary shape, without adding materials and using a single
laser process step.
