All solid-state blue room-temperature thulium-doped upconversion fibre laser

Abstract

Following the report by Grubb we describe an all solid state, single wavelength pumped, cw, room temperature, upconversion laser which has operated in the blue between 475nm and 483nm or in the near infrared at 778nm. We have pumped this device at both longer and shorter wavelengths than those reported by Grubb. The system uses Yb-doped silica fibre to convert the output from a diode pumped Nd:YLF laser to a wavelength in the range 1.05µm to 1.18µm. This is used to pump a Tm-doped ZBLAN fibre giving rise to an upconversion process which involves the sequential absorption of three pump photons to populate the 1G4 upper laser level as shown in Fig 1