650-nm laser emission under upconversion pumping at 1.064 μm in Tm+3: 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].…”

“…Among rare earth (RE) ions, Tm +3 showed a versatile candidate that converts low-energy infrared photons to high-energy photons in the visible and ultraviolet spectral under up-conversion processes [5][6][7][8]. The first upconversion-pumped visible laser was demonstrated in a Tm +3 -doped ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF (ZBLAN) fiber at 455 nm ( 1 D 2 → 3 F 4 ) and 480 nm ( 1 G 4 → 3 H 6 ) with additionally some UV fluorescence at 288 nm ( 1 I 6 → 3 H 6 ) [9].…”

“…Photo-degradation is the absorption of visible and short wavelengths or so called color centre problem. Stability and power scaling can be reached with the improvement of the ZBLAN material through the modulation of the component of the fiber, introducing other ions into the core of the fiber to preclude the photo-degradation effect [7]. Additionally, fibers with small numerical aperture (NA) by adjusting the refractive indices of the fiber core and cladding may also reduce the photo-darkening effect [2].…”

“…Additionally, fibers with small numerical aperture (NA) by adjusting the refractive indices of the fiber core and cladding may also reduce the photo-darkening effect [2]. Usually, this effect can be removed almost entirely by circulating blue light or wavelength of 514 nm through the fiber core [2,7]. This problem of photo-degradation associated with formation of color centers is solved temporally by circulating 514 nm through the fiber core as reported in ref.…”

“…This problem of photo-degradation associated with formation of color centers is solved temporally by circulating 514 nm through the fiber core as reported in ref. [7].…”