Mechanisms of upconverted fluorescence in an Er3+ doped LiNbO3 single crystal

Abstract

Two different upconversion mechanisms leading to green fluorescence in an Er3+ doped LiNbO3 crystal have been investigated with pulse laser excitations at the wavelengths of 1064 and 980 nm. In the case of the 1064 nm pump, the Er3+ ions become excited by the phase-matched second harmonic wave generated in the LiNbO3 crystal, whereas sequential two-photon absorption is mainly responsible for the excitation with the 980 nm pump. The second harmonic excitation is of an order of magnitude more efficient than the sequential two photon excitation in the upconversion of the near-infrared pump photons to the green fluorescence.

Blue luminescence in Tm3+-doped KGd(WO4)2 single crystals

“…In this paper we report the generation of blue emissions in thulium-doped KGd(WO 4 ) 2 (hereafter KGW) single crystals at 454 and 479 nm by the sequential two-photon excitation process (STEP) under a single pumping at 688 nm. This STEP mechanism was observed in other lanthanide-doped single crystals [6]. The difference between STEP and ESA up-conversion processes is that in the STEP case the terminal state of the first photon absorption transition is the initial state for the second absorption transition, while in the ESA case this is not true [7].…”

Spectroscopic characteristics of 1.54μm emission in Er/Yb:LiNbO3 crystals tridoped with In3+ ions

“…Researches in this area based on Er 3+ -doped silica glasses, polymers and crystals have been widely demonstrated [3][4][5]. Among these laser hosts, Er:LiNbO 3 crystal is of particular interest since the well-known versatile LiNbO 3 crystal, exhibiting electro-optic, piezo-electric and nonlinear optical physical properties, successfully combines with the amplifying and lasing characteristics of Er 3+ ion [6][7][8]. The 1.54 m emission arising from the 4 I 13/2 → 4 I 15/2 transition of Er 3+ ion matches well with the third fiber-optics communication window [9].…”

Spectroscopic analysis of Er3+ transition in Mg/Er-codoped LiNbO3 crystal

“…RE ions are being served as potential active ions for laser materials due to their good luminescent properties [5][6][7]. RE-doped LiNbO 3 crystal is extensively studied for its potential in compact solid-state laser material since Ross et al [3] obtained high conversion efficiency in periodically poled structures based on LiNbO 3 , especial on Nd 3+ -or Er 3+ -doped LiNbO 3 [8][9][10][11][12][13]. Unfortunately, pure LiNbO 3 crystal is highly susceptible to optical damage that brings about light-induced refractive index changes, which further limits possible applications [14,15].…”