Yb Sensitized Near-Stoichiometric Er:LiNbO₃ Single Crystal: A Matrix for Optical Communication and Upconversion Emission

Abstract

Ytterbium and erbium codoped crystals have attracted considerable interest in the application of eye-safe laser, upconversion laser, and low-loss optical communication. Despite the lithium niobate (LiNbO3, LN) single crystal has been accepted as an ideal crystal matrix for Yb3+ and Er3+ ions possessing significant application potential in self-upconversion laser, the Yb and Er codoped near-stoichiometric LN (NSLN) crystal has rarely been studied. This is due to the difficulty of the NSLN crystal growth compared with that of the congruent LN (CLN). In this paper, an Yb, Er codoped near-stoichiometric LN (Yb, Er:NSLN) crystal was grown by the Czochrolski method for the first time. Spectra studies showed the constrained peak splitting at 378, 526, and 650 nm of the Yb, Er:NSLN crystal compared with Yb, Er:CLN crystal. It was attributed to the low concentration of intrinsic defects which constrained the Stark-split of the three energy levels of 4G11/2, 2H11/2, and 4F9/2 energy states. Some spectral changes are verified induced by the stoichiometric composition in the polarized emission spectra. The Yb, Er:NSLN crystal has high potential in upconversion laser application.

Microstructure and domain engineering of lithium niobate crystal films for integrated photonic applications

“…The waveguide showed no photorefractive damage at a high SH optical intensity of ∼10 MW cm −2 after many hours of optical pumping 120 . Furthermore, stoichiometric LN crystals have a smaller coercive field of~3.5 kV mm −1 and a completely crystalline structure [146][147][148][149][150][151][152] . Therefore, stoichiometric LN films should be more suitable for ultralow-loss nanophotonic waveguides 153 and can be poled with a smaller electric field.…”

Efficient Second- and Third-Harmonic Generations in Er3+/Fe2+-Doped Lithium Niobate Single Crystal with Engineered Surficial Cylindrical Hole Arrays

“…Due to the large nonlinear polarizability, wide optical window, excellent nonlinearity, and electro-optical and piezoelectric properties, LiNbO 3 single-crystal and thin films are also widely used in laser medical treatment, optical communication, laser processing, and holography [ 26 , 27 , 28 , 29 ]. In terms of second- and third-harmonic generations, picosecond 531 nm green and 385 nm violet light generations were performed in a LiNbO 3 optical superlattice by using the quasi-phase-matching technique [ 30 ], and efficient second- and third-order nonlinear processes were demonstrated by using a waveguide structure and ferroelectric-domain-inverted grating [ 31 ].…”

Origin of Ferroelectric Modification: The Thermal Behavior of Dopant Ions

“…Iyi et al proposed a structure model of 5 mol % Mg doped CLN as [Li 0.90 Mg 0.05 □ 0.05 ]­[Nb]­O 3 according to the Li-vacancy model, where antisite Nb Li defects were eliminated and charge compensation takes place via Li-vacancies . In addition, the rare-earth active ions (Re 3+ : Nd 3+ , Er 3+ , Yb 3+ , et al) doped LN crystals (Re:CLN) were often researched as multifunctional composite crystals. − It is accepted that the rare-earth ions are located in Li octahedrons but in off-centered positions by different amounts along the c -axis. , …”