Upconversion CW laser at 284 nm in a Nd:YAG-pumped double-cladding thulium-doped ZBLAN fiber laser

Generation of Short Wavelength in Up-Conversion of Tm<sup>+3</sup> Doped Fluoride Glass and Its Application in Fiber Lasers

“…Based on our measured emission spectrum and time resolved spectroscopy we proposed the excitation mechanism as following: the first three excitation steps are assumed to occur as described in [6,7,11] . This will reduce the distance between Tm +3 ions resulting in efficient ETU processes and leading to a strong UV emissions [12,13].…”

Revisiting literature observations on photodarkening in Yb3+doped fiber considering the possible presence of Tm impurities

“…In addition, it was shown in [73] that increasing the ratio of the concentration of Yb 3+ to that of Tm 3+ leads to an increase in the populations of the 1 I 6 and 1 D 2 levels, and therefore an enhanced emission in the UV. The ESA up-conversion phenomenon is so efficient in Tm 3+ that a laser at 284 nm was demonstrated [74]], showing that one cannot ignore these processes.…”

UV emission properties of thulium-doped fluorozirconate glasses

“…The latter has been a subject of extensive investigations focused specifically on blue-violet luminescence and lasing properties of thulium-doped fibers [7]. Nevertheless, until now only a few papers concerning UV luminescence properties of Tm:ZBLAN glasses have been published [8][9][10], including very recent, spectacular result of UV (284 nm) lasing in Tm:ZBLAN fibers observed under up-conversion pumping [11], which confirms that the subject had not been exhausted and stimulates further studies on UV emission phenomena in thulium-doped systems.…”