Visible and near infra-red up-conversion in Tm^3+/Yb^3+ co-doped silica fibers under 980 nm excitation

Abstract

The spectroscopic properties of Tm(3+)/Yb(3+) co-doped silica fibers under excitation at 980 nm are reported. Three distinct up-conversion fluorescence bands were observed in the visible to near infra-red regions. The blue and red fluorescence bands at 475 and 650 nm, respectively, were found to originate from the (1)G(4) level of Tm(3+). A three step up-conversion process was established as the populating mechanism for these fluorescence bands. The fluorescence band at 800 nm was found to originate from two possible transitions in Tm(3+); one being the transition from the (3)H(4) to (3)H(6) manifold which was found to dominate at low pump powers; the other being the transition from the (1)G(4) to (3)H(6) level which dominates at higher pump powers. The fluorescence lifetime of the (3)H(4) and (3)F(4) levels of Tm(3+) and (2)F(5/2) level of Yb(3+) were studied as a function of Yb(3+) concentration, with no significant energy back transfer from Tm(3+) to Yb(3+) observed.

Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere

“…When Tm 3+ /Yb 3+ is codoped, the wavelength center is around 475 nm, and has other bands. 26 In Ytterbium-doped silica fiber, 27 an experimental and theoretical investigation of the nonlinear transmission coefficient in a set of Ytterbium-doped silica fibers with various concentrations of Yb 3+ ions at continuous-wave 980-nm pumping is reported. They proposed a scheme of energy levels of Ytterbium to suppose existence of Yb 3+ -Yb 3+ IPs to explain the following processes: The cooperative de-excitation of two adjacent excited ions of Yb 3+ composing a pair via non-radiative multi-phonon relaxation and also via the spontaneous cooperative emission process.…”

Emission decay and energy transfer in Yb/Tm Y-codoped fibers based on nano-modified glass

“…Indeed, the Y2O3 helps to create nano-structured YAS glass phase in the host and acts as a glass network generator [23][24][25]. The Al2O3 increases the refractive index (RI) of silica by 2.3x10 -3 per mole and is used as intermediate core glass network modifier [26]. It helps to distribute Tm 3+ and Yb 3+ ions homogeneously to decrease phonon energy of silica glass [26].…”

“…The Al2O3 increases the refractive index (RI) of silica by 2.3x10 -3 per mole and is used as intermediate core glass network modifier [26]. It helps to distribute Tm 3+ and Yb 3+ ions homogeneously to decrease phonon energy of silica glass [26]. The modified silica glass host is chosen due to its optical transparency from 200 nm to beyond 3000 nm wavelength region [27].…”

Blue and near-infrared up-conversion in double-air-cladding Tm3+-doped silica fiber under 1064 nm excitation

“…In addition, Tm 3? -doped materials have been investigated extensively to obtain up-conversion luminescence covering from violet to near-infrared (NIR) wavelengths (Wang et al 2008;Chen et al 2013;Mahalingam et al 2012;Simpson et al 2008), especially blue up-conversion luminescence (Zhang et al 2005b;Uchida et al 2014Uchida et al , 2015Thrash and Johnson 1994;Ostermayer et al 1971). However, studies are mainly focused on the Tm 3?…”