Coherent Emission from Rare Earth Ions in Electro-optic Crystals

Abstract

We report the observation of coherent emission from three rare-earth ions in electro-optic crystals. Oscillation is observed from Nd3+ ions in Bi4Ge3O12, LiNbO3, and Ba0.75Ca0.25Nb26O at room temperature, and from Tm3+ and Ho3+ ions in LiNbO3 at 77°K. Second-harmonic radiation is obtained from LiNbO3:Tm3+ and electric-field modulation of threshold is observed for certain crystals of LiNbO3:Nd3+. The latter effect is believed to arise from crystal strain. The propagation angle for phase-matched second-harmonic generation is calculated to lie at 43° to the c axis for both LiNbO3:Tm3+ and LiNbO3:Ho3+ at 77°K. Phasematched second-harmonic generation from LiNbO3:Nd3+ is not possible, since the maser line is an extraordinary wave. However, the polarization of the maser line in LiNbO3:Nd3+ is appropriate for phasematched parametric frequency conversion in the near infrared. Attempts to observe such radiation were not successful due to the limited power available in the fundamental.

Optical decoherence and energy level structure of 0.1%Tm3+:LiNbO3

“…20 were compatible with our observed spectra, but the partial list of energy levels that were presented in Ref. 26 agree with ours reasonably well. The energies that we list for higher levels were referenced to the main peak at 12591.5 cm −1 ; the very broad linewidth of that 3 H 6 (1)-3 H 4 (1) transition can mean an uncertainty of up to 20 cm −1 .…”

“…The energy levels are listed in Table III, along with the corresponding values determined in Ref. 26. Three transitions were very weak in the spectra.…”

Spectroscopic and Laser Properties of LiNbO3:Dy3+Crystals

“…Laser action in Nd3+ , H03+ and Tm3+ doped LiΝbO3 (LNB) has been reported [1] and spectroscopic properties of these crystals as well as Er3+ [2] and Cr3+ [3] doped materials have been studied. Diode pumped channel waveguide lasers have been realised in Nd3+ [4], Yb3+ [5] and Er3+ [6] activated LiNbO 3, Recent reports indicate the interest of activating the optical glasses by Dy3+ ions for the purposes of 1.3 im band fiber telecommunication [7] and dysprosium is being compared with the most widely used dopant at present -praseodymium [8].…”

Efficient 1856 nm emission from Tm,Mg:LiNbO_3 laser

“…Moreover, periodically poled LiNbO 3 structures have enabled new features of frequency conversion by quasi-phase matching for the integrated devices [4]. The further study of LiNbO 3 as laser host for rare-earth ions has been extensively investigated [5,6]. It is bringing forth new integration, in which laser oscillation, electro-optic and nonlinear optics effects can be integrated within just one crystal.…”