High Defect Tolerance Breaking the Design Limitation of Full-Spectrum Multimodal Luminescence Materials.

With the development of optical anti-counterfeiting and the increasing demand for high-level information encryption, multimodal luminescence (MML) materials attract much attention. However, the discovery of these multifunctional materials is very accidental, and the versatile host suitable for developing such materials remains unclear. Here, a grossite-type fast ionic conductor CaGaO, characterized by layered and tunnel structure with excellent defect tolerance, is found to meet the needs of various luminescent processes.

Study on the optical mechanism of photorefractive resistance in Zr-doped lithium niobate crystals from first-principle calculations.

Lithium niobate on insulator (LNOI) has attracted widespread interest due to the excellent optical performance of lithium niobate crystals and the integration characteristics of thin film devices. With the improvement of the integration level of photonic integrated chips and the increase in light intensity inside the chip, the impact of optical damage in LNOI on-chip performance has attracted attention. One effective way to suppress the optical damage of lithium niobate is to dope it with Zr to form LiNbO (LiNbO:Zr), which is famous for its high resistance to optical damage from ultraviolet to visible spectrum.

On-chip erbium-ytterbium-co-doped lithium niobate microdisk laser with an ultralow threshold.

Erbium-ion-doped lithium niobate (LN) microcavity lasers working in the communication band have attracted extensive attention recently. However, their conversion efficiencies and laser thresholds still have significant room to improve. Here, we prepared microdisk cavities based on erbium-ytterbium-co-doped LN thin film by using ultraviolet lithography, argon ion etching, and a chemical-mechanical polishing process.

On-chip ytterbium-doped lithium niobate waveguide amplifiers with high net internal gain.

Integrated optical systems based on lithium niobate on insulator (LNOI) have shown great potential in recent years. However, the LNOI platform is facing a shortage of active devices. Considering the significant progress made in rare-earth-doped LNOI lasers and amplifiers, the fabrication of on-chip ytterbium-doped LNOI waveguide amplifiers based on electron-beam lithography and inductively coupled plasma reactive ion etching was investigated.

Integrated ytterbium-doped lithium niobate microring lasers.

Integrated and stable microlasers are indispensable building blocks of micro-photonics. Here, we report the realization of an ytterbium-doped lithium niobate microring laser operating in the 1060-nm band under the pump of a 980-nm-band laser. The monolithic laser has a low threshold of 59.

Intense Luminescence and Good Thermal Stability in a Mn-Activated Mg-Based Phosphor with Self-Reduction.

White light-emitting diodes provide widespread applications in lighting, electronic equipment, and high-tech displays. However, thermal quenching effect severely limits their practical application. Here, we developed an orange-red phosphor β-KMg(PO):Mn, which emits bright orange-red light when excited by ultraviolet light without the energy transfer of sensitizer, owing to the strong crystal field provided by β-KMg(PO) for Mn.

On-chip ytterbium-doped lithium niobate microdisk lasers with high conversion efficiency.

Integrated optical systems based on lithium niobate on insulator (LNOI) have attracted the interest of researchers. Recently, erbium-doped LNOI lasers have been realized. However, the reported lasers have a relatively lower conversion efficiency and only operate in the 1550 nm band.

Self-Reduction-Related Defects, Long Afterglow, and Mechanoluminescence in Centrosymmetric LiZnGeO:Mn.

Mechanoluminescent materials have shown great application potential in the fields of stress detection, anti-counterfeiting, and optical storage; however, its development is hindered by the unclear mechanism. Different from the mainstream exploration of new mechanoluminescent materials in non-centrosymmetric structures, a centrosymmetric mechanoluminescent material LiZnGeO:Mn is synthesized by a standard high-temperature solid-state reaction in an ambient atmosphere. Combined with the Rietveld refinement, photoluminescence, electron spin resonance, and X-ray photoelectron spectroscopy, it is proved that the increase in oxygen vacancies is accompanied by the self-reduction process from Mn to Mn, and the mechanism of mechanoluminescence is clarified through the afterglow and thermoluminescence spectra.

On-chip erbium-doped lithium niobate microring lasers.

Lithium niobate on insulator (LNOI), regarded as an important candidate platform for optical integration due to its excellent nonlinear, electro-optic, and other physical properties, has become a research hotspot. A light source, as an essential component for an integrated optical system, is urgently needed. In this Letter, we reported the realization of 1550 nm band on-chip LNOI microlasers based on erbium-doped LNOI ring cavities with loaded quality factors higher than 1 million at ∼970, which were fabricated by using electron beam lithography and inductively coupled plasma reactive ion etching processes.

Construction of a novel mechanoluminescent phosphor LiMgGeO:Mn by defect control.

Lattice defect plays a significant role in the optical properties of elastic mechanoluminescent materials, which could be modulated by cationic non-equivalent replacement. Here, a series of novel mechanoluminescent phosphors Li2-xMgGeO4:xMn2+ (0 ≤ x ≤ 0.025) were synthesized via a high-temperature solid-state reaction method in an ambient atmosphere.

Correction: Saeed, S., et al. Enhancement of Photorefraction in Vanadium-Doped Lithium Niobate through Iron and Zirconium Co-Doping. Materials 2019, Vol. 12, 3143.

The authors wish to make the following corrections to this paper [...

Interaction between Mo and intrinsic or extrinsic defects of Mo doped LiNbO from first-principles calculations.

Lithium niobate (LiNbO, LN) plays an important role in holographic storage, and molybdenum doped LiNbO (LN:Mo) is an excellent candidate for holographic data storage. In this paper, the basic features of Mo doped LiNbO, such as the site preference, electronic structure, and the lattice distortions have been explored from first-principles calculations. Mo substituting Nb with its highest charge state +6 is found to be the most stable point defect form.

Microdisk resonators with lithium-niobate film on silicon substrate.

In this paper, we report the fabrication of lithium niobate (LN) microdisk resonators on a pulsed-laser deposited polycrystalline LN film on a silicon substrate rather than commercially provide LN film on insulator. The quality factor of these polycrystalline LN microdisks were measured above 3.4×10 in the 1550-nm band.

Linear Tuning of Phase-Matching Temperature in LiNbO:Zr Crystals by MgO Co-Doping.

We grew a series of co-doped LiNbO crystals with fixed 1.5 mol % ZrO and various MgO concentrations (1.0, 3.

p-Type conductivity mechanism and defect structure of nitrogen-doped LiNbO from first-principles calculations.

Most metal-doped lithium niobates (LiNbO3, LN) exhibit n-type conductivity. The absence of p-type conductive LiNbO3 limits its application. Based on the finding that p-type conductive LiNbO3 can be realized by doping with a non-metallic element N, we investigate the most stable defect configurations and formation energies of LiNbO3 doped with non-metal nitrogen (LN:N) by first-principles calculations.

Enhancement of Photorefraction in Vanadium-Doped Lithium Niobate through Iron and Zirconium Co-Doping.

A series of mono-, double-, and tri-doped LiNbO crystals with vanadium were grown by Czochralski method, and their photorefractive properties were investigated. The response time for 0.1 mol% vanadium, 4.

Fabrication and Characteristics of Heavily Fe-Doped LiNbO/Si Heterojunction.

A series of heavily Fe-doped LiNbO (LN:Fe) crystals were grown via the Czochralski method. The dark- and photo-conductivity of the 5.0 wt.

Synthesis, structure and characterization of M(IO)(HIO) (M = Ca, Sr) as new anhydrous alkaline earth metal bis-iodate hydrogeniodate compounds.

Two new metal iodates, namely, M(IO)(HIO) (M = Ca, Sr), were successfully synthesized by the hydrothermal method, and their structures were determined by single-crystal X-ray diffraction. They were found to be isostructural, and crystallized in the monoclinic space group P2/n with the lattice parameters: a = 6.9647(14) Å, b = 15.

Recent Progress in Lithium Niobate: Optical Damage, Defect Simulation, and On-Chip Devices.

Lithium niobate (LN) is one of the most important synthetic crystals. In the past two decades, many breakthroughs have been made in material technology, theoretical understanding, and application of LN crystals. Recent progress in optical damage, defect simulation, and on-chip devices of LN are explored.

P-Type Lithium Niobate Thin Films Fabricated by Nitrogen-Doping.

Nitrogen-doped lithium niobate (LiNbO₃:N) thin films were successfully fabricated on a Si-substrate using a nitrogen plasma beam supplied through a radio-frequency plasma apparatus as a dopant source via a pulsed laser deposition (PLD). The films were then characterized using X-Ray Diffraction (XRD) as polycrystalline with the predominant orientations of (012) and (104). The perfect surface appearance of the film was investigated by atomic force microscopy and Hall-effect measurements revealed a rare p-type conductivity in the LiNbO₃:N thin film.

Effect of Defects on Spontaneous Polarization in Pure and Doped LiNbO₃: First-Principles Calculations.

Numerous studies have indicated that intrinsic defects in lithium niobate (LN) dominate its physical properties. In an Nb-rich environment, the structure that consists of a niobium anti-site with four lithium vacancies is considered the most stable structure. Based on the density functional theory (DFT), the specific configuration of the four lithium vacancies of LN were explored.

Analysis of the structure and abnormal photoluminescence of a red-emitting LiMgBO:Mn phosphor.

Mn is attracting increasing attention due to its potential application as an activated ion in the phosphors. In this study, a rare-earth free phosphor, LiMgBO:Mn, was synthesized using a high temperature solid-state reaction. Combined with X-ray diffraction and PL/PLE as well as first-principles calculation, the coordination environment of Mn was disclosed, revealing that Mn ions were inclined to occupy two partially filled Li sites.

Room temperature 90° phase-matching in zirconium and magnesium co-doped lithium niobate crystals.

Laser has been widely used in many aspects, by now it is difficult to get each frequency that we want, and frequency conversion is an effective way to obtain different frequency laser through a nonlinear optical crystal. MgO-doped LiNbO (Mg:LN) crystal has usually been used for second harmonic generation (SHG) through temperature-matching configuration with a stove, till now a room temperature 90° phase-matching is still lacking. Here we find that the SHG of Nd:YAG laser is achieved at 26.

Crystal Structure of High-Temperature Phase β-NaSrBO3 and Photoluminescence of β-NaSrBO3:Ce(3.).

α-NaSrBO3 is an excellent phosphor host for phosphor-converted white light-emitting diode (w-LED) application with very interesting properties. However, it undergoes a phase transformation to β-NaSrBO3 at the LED working temperature. In this study, the high-temperature phase β-NaSrBO3 was stabilized to room temperature by introducing Na(+) and Ce(3+) via a high-temperature solid-state reaction method.