Borate Crystals Research Articles

High power picosecond green and deep ultraviolet generations with an all-fiberized MOPA.

We demonstrate high power picosecond green and deep ultraviolet (DUV) lasers based on an all-fiberized master oscillator power amplifier (MOPA). The main power amplifier is fabricated with a highly Yb-doped large mode area (LMA) silicate glass fiber. It delivers 75.2-W laser output at 1029 nm with a pulse repetition rate of 10 MHz and a pulse duration of 70 ps. With a lithium triborate (LBO) crystal, a 43.0-W green output at 514.5 nm has been achieved with a pulse duration of 55 ps. With a caesium lithium borate (CLBO) crystal, a 14.5-W picosecond DUV output at 257 nm has been generated, which is the highest power for the all-fiber based DUV laser, to the best of our knowledge.

Effect of bond valence sum on the structural modeling of lead borate glass

The structural model of 66.7PbO-33.3B2O3 glass was constructed using a reverse Monte Carlo (RMC) method, in which bond valence sum (BVS) was added as a constraint condition to suppress formation of unrealistic local structures. Based on the crystal structures, the optimal BVS calculating conditions were determined. As a result, BVS distributions with small deviation were successfully achieved without lowering the reproducibility of other experimental constraints. The geometric asymmetry of PbOn polyhedra was evaluated from the eccentric distance between Pb and gravity center of oxygen atoms. The average eccentric distance was shorter than that in the lead borate crystals, indicating less asymmetry of PbOn units in the RMC glass model. The connectivity between BOn and PbOn units was investigated. It was consequently concluded that the glass had a different network structure from the crystal with the same composition, which might be due to the different chemical bonding character between the lead borate glasses and crystals.

High-Precision Voltage Measurement for Optical Quantum Computation

This paper presents a theoretical study into the use of optical systems for quantum computation. The study results pertain to quantum sampling and quantum communication and provide a basis for further research and the development of a physical implementation. We propose an optical superstructure that can implement specific computation processes and algorithms. The superstructure is composed of nonlinear optical units, such as beta barium borate crystals. The units are positioned in series, powered by a pulse laser pump, and culminate in a beam splitter that generates the output state of a number of entangled photon pairs. Computation is achieved by entanglement propagation via beam splitters and adjustable phase shifters, which set related parameters. Demonstrating a two-component case, we show how a series of cosine-based components can be implemented. The obtained results open a broad front for future research. Future work should investigate the construction of a quantum optimizer using quantum sampling methods and also investigate high-precision temporal voltage measurement, which is a key procedure for the construction of high-fidelity devices.

Bi3TeBO9: A Promising Mid-Infrared Nonlinear Optical Crystal with a Large Laser Damage Threshold.

Mid-infrared (mid-IR) nonlinear optical (NLO) crystals are key materials in the field of laser technology. Nevertheless, the applications of these significant optical materials are always limited by their low laser damage threshold (LDT). Here, an oxide mid-IR NLO crystal, Bi3TeBO9, with a large LDT was discovered. The centimeter-sized Bi3TeBO9 single crystal was successfully grown by the top-seeded solution growth (TSSG) method. The Bi3TeBO9 features a high LDT of 450 MW/cm2 (∼15 × AgGaS2) and the widest transparent range (0.35-7.10 μm) among known borate crystals. The second-harmonic generation (SHG) effect is about 1.6 times that of KDP. First-principles calculations and structural analysis show that the optical characteristics of Bi3TeBO9 are mainly affected by distorted [BiO6] groups. Furthermore, its thermal characteristics including specific heat, thermal diffusivity, thermal conductivity, and thermal expansion were also measured.

Broadband terahertz time-domain polarimetry based on air plasma filament emissions and spinning electro-optic sampling in GaP.

We report on a time-domain polarimetry (TDP) system for generating and detecting broadband terahertz (THz) waves of different polarization angles. We generate THz waves from two-color laser filaments and determine their polarization states with a detection bandwidth of up to 8 THz using a spinning gallium phosphide crystal. The polarization of THz emission can be controlled by adjusting the position and tilt angle of the β-barium borate crystal. We characterize the precision of this system for polarimetric measurements at fixed time delay to be and for complete time-domain waveforms. We also demonstrate the feasibility of our TDP system by measuring broadband optical properties of anisotropic samples in both transmission and reflection geometries. The THz-TDP technique can be easily integrated in conventional THz time-domain spectroscopy setups using nonlinear crystal detectors.

Fluorescence and Optical Studies of Sodium Carbonate Boric Acid - ANLO Single Crystal

The single crystals of sodium carbonate borate(SCB) were grown by evaporation technique. The crystallinity of SCB was determined using powder XRD. The optical characteristics of SCB are investigated using UV-Vis spectral measurements. At 650 nm, a significant red emission was found in the SCB fluorescence spectrum. Microhardness testing was used to determine the sample's mechanical strength.

Optical and thermoluminescence response of rare earth activated aluminium borate crystals

Rare earth elements of gadolinium and dysprosium at different mole concentrations doped on aluminium borate were studied for their structural, optical and thermoluminescence properties. The samples of Al2(B4O7)3:Gd/Dy were prepared by using the high temperature solid state sintering technique. X-ray diffraction and Scanning electron microscopy showed a difference in both the crystallite size and the particle size for the Undoped, gadolinium doped and dysprosium doped aluminium borate. Fourier transform infrared spectroscopy study identified different functional groups. The optical properties revealed a variation in the absorbance when compared with the different concentrations of the Gd and Dy dopants used on aluminium borate. Thermoluminescence from all the samples measured at 1oCs−1 following irradiation to 160Gy shows a major peak at 90 °C with a secondary, weak intensity peak along the high temperature region of the glow curve. The dose response of the 0.4% mole concentration of Dy doped on aluminium borate showed a linear response from 40 to 500 Gy.

Synthesis and flux-growth of rare-earth magnesium pentaborate crystals RMgB5O10 (R = Y, Gd, La, Tm and Yb)

For the first time, to our knowledge, RMgB5O10 (R = Tm, Yb) compounds have been synthesized by solid-phase synthesis. For RMgB5O10 (R = Y, La, Gd) the growth conditions are optimized in the temperature range 1000 – 800 °C by the flux method with a change in the concentration of the crystal-forming component vs the concentration of the solvent in the initial load. Using the data obtained the RMgB5O10 single crystals with optical quality and dimensions up to 20 mm × 20 mm × 10 mm co-activated with erbium, ytterbium, and neodymium were growth by the solution growth from dipped seed (SGDS) method. (Er,Yb):RMgB5O10 in general have characteristics similar to the previously studied laser crystals of huntite-type borates (Er,Yb):RAl3(BO3)4 (R = Y, Gd, Lu) and appear to be an alternative material due to a simpler growing and processing technology.

Compact, single-mode fiber-coupled, correlated photon pair source based on type-I beta-barium borate crystal

A small, portable, high-flux correlated photon-pair source has been designed and constructed from simple opto-mechanical parts. Unique to this device is its straightforward alignment process, together with the direct coupling of signal and idler photons into polarization-maintaining single-mode optical fibers. Spontaneous parametric down-conversion is used to produce photon pairs in β-barium borate (BBO) at a center wavelength of 810 nm. Owing to the applied type-I phase-matching, coincident photons have identical polarization. The estimated fiber-coupling efficiency is 51%, the measured photon and coincidence flux are 636 and 130 kHz/mW, respectively, normalized to pump power (44 mW). The source has an extremely wide wavelength spectrum of 202-nm FWHM, measured at the fiber output, which limits the actual heralding ratio to 20%.

Cascaded frequency up-conversion of bright squeezed vacuum: spectral and correlation properties.

High-gain parametric down-conversion (PDC) is inevitably accompanied by cascaded up-conversion (CUpC) of PDC radiation in a nonlinear crystal even if CUpC is nonphase matched. Here we study experimentally and theoretically the spectral properties of broadband phase-matched and nonphase-matched CUpC radiation in a beta barium borate (BBO) crystal. Our calculations of the normalized second-order correlation function predict the super-bunching of CUpC radiation.

A Low-wavelength host absorption edge of LiB-=SUB=-3-=/SUB=-O-=SUB=-5-=/SUB=- and Li-=SUB=-2-=/SUB=-B-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=- crystals

We have carried out an experimental study of the VUF- edge of the optical host absorption of lithium borate crystals LiB3O5 (LBO) and Li2B4O7 (LTB). The transmission (T=293 K) and absorption (T=80, 293 K) spectra were studied, the short-wavelength edge of the transparency band (cutoff wavelength) and the energy position of the edge fundamental absorption at which the absorption coefficient k=50 cm-1 were determined. The absorption edge temperature shift coefficient -(3-4.7)·10-4 eV/K was determined. The dependence of the absorption edge parameters of oriented LBO normal Y and LBO normal X crystals has been studied. Based on low-temperature reflection spectra (T=10 K, theta=17o, E=4-32 eV) the Kramers-Kronig method was used to calculate the spectra of optical constants: refractive index (n) and absorption index (k), real (ε1) and imaginary (ε2) parts of the complex permittivity, as well as the absorption coefficient μ. The lowest energy peak, due to electronic transitions from the top of the valence band to the states of the bottom of the conduction band, was studied in the ε_2(E) spectrum, the thresholds for interband transitions were determined (Eg at T=10 K): 8.5-8.6 eV(LBO normal Y), 8.6-8.7 eV (LBO normal X) and 8.8-8.9 eV (LTB). The origin of the fundamental absorption edge of lithium borates is discussed. Keywords: Lithium triborate LiB3O5, lithium tetraborate Li2B4O7, host absorption edge, optical properties.

Длинноволновый край фундаментального поглощения кристаллов боратов лития LiB-=SUB=-3-=/SUB=-O-=SUB=-5-=/SUB=- и Li-=SUB=-2-=/SUB=-B-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=-

We have carried out an experimental study of the VUV edge of the optical host absorption of lithium borate crystals LiB3O5 (LBO) and Li2B4O7 (LTB). The transmission (T = 293 K) and absorption (T = 80, 293 K) spectra are studied, the short-wavelength boundary of the transparency band (cutoff wavelength) and the energy position of the edge are determined. fundamental absorption at which the absorption coefficient is k = 50 cm-1. The transmission (T = 293 K) and absorption (T = 80, 293 K) spectra were studied, the short-wavelength edge of the transparency band (cutoff wavelength) and the energy position of the edge fundamental absorption at which the absorption coefficient k = 50 cm-1 were determined. The absorption edge temperature shift coefficient −(3–4.7)·10-4 eV/K was determined. The dependence of the absorption edge parameters of oriented LBO ⊥ Y and LBO ⊥ X crystals has been studied. Based on low-temperature reflection spectra (T = 10 K, θ = 17◦, E = 4–32 eV) the Kramers – Kronig method was used to calculate the spectra of optical constants: refractive index (n) and absorption index (k), real (ε1) and imaginary (ε2) parts of the complex permittivity, as well as the absorption coefficient μ. The lowest energy peak, due to electronic transitions from the top of the valence band to the states of the bottom of the conduction band, was studied in the ε2(E) spectrum, the thresholds for interband transitions were determined (Eg at T = 10 K): 8.5–8.6 eV (LBO ⊥ Y), 8.6–8.7 eV (LBO ⊥ X) and 8.8–8.9 eV (LTB). The origin of the fundamental absorption edge of lithium borates is discussed.

A Low-Wavelength Host Absorption Edge of Cesium-Lithium Borate CsLiB-=SUB=-6-=/SUB=-O-=SUB=-10-=/SUB=-

We have carried out an experimental study of the VUV edge of the optical host absorption of cesium-lithium borate crystals CsLiB6O10 (CLBO). The transmission (T=293 K) and absorption (T = 80, 293 K) spectra were studied, the short-wavelength edge of the transparency band (cutoff wavelength) and the energy position of the edge fundamental absorption at which the absorption coefficient k=50 cm-1 were determined. The absorption edge temperature shift coefficient -5.5·10-4 eV/K was determined. Based on low-temperature reflection spectra (T=10 K, theta=17o, E=7-30 eV) the Kramers-Kronig method was used to calculate the spectra of optical constants: refractive index (n) and absorption index (k), real (ε1) and imaginary (ε2) parts of the complex permittivity , as well as the absorption coefficient μ. The lowest energy peak, due to electronic transitions from the top of the valence band to the states of the bottom of the conduction band, was studied in the ε2(E) spectrum, the thresholds for interband transitions were determined Eg=7.95 eV. The origin of the fundamental absorption edge of cesium-lithium borate is discussed. Keywords:: Cesium-lithium borate CsLiB6O10 (CLBO), host absorption edge, optical properties.

Длинноволновый край фундаментального поглощения кристаллов цезий-литиевого бората CsLiB-=SUB=-6-=/SUB=-O-=SUB=-10-=/SUB=-

We have carried out an experimental study of the VUV edge of the optical host absorption of cesium-lithium borate crystals CsLiB6O10 (CLBO). The transmission (T = 293K) and absorption (T = 80, 293 K) spectra are studied, the short-wavelength boundary of the transparency band (cutoff wavelength) and the energy position of the edge are determined. fundamental absorption at which the absorption coefficient is k = 50 cm−1. The transmission (T = 293 K) and absorption (T = 80, 293 K) spectra were studied, the short-wavelength edge of the transparency band (cutoff wavelength) and the energy position of the edge fundamental absorption at which the absorption coefficient k = 50cm−1 were determined. The absorption edge temperature shift coefficient −(3–4.7)·10−4 eV/K was determined. The dependence of the absorption edge parameters of oriented LBO⊥ X and LBO⊥ Y crystals has been studied. Based on low-temperature reflection spectra (T =10K, θ =17◦, E = 4–32 eV ) the Kramers –Kronig method was used to calculate the spectra of optical constants: refractive index (n) and absorption index (k), real (ε1) and imaginary (ε2) parts of the complex permittivity , as well as the absorption coefficient μ. The lowest energy peak, due to electronic transitions from the top of the valence band to the states of the bottom of the conduction band, was studied in the ε2(E) spectrum, the thresholds for interband transitions were determined (Eg at T = 10K): 7.95 eV. The origin of the fundamental absorption edge of cesium-lithium borate is discussed.

2‐Quinolyl Benzodiazaborine: A Tunable Platform for Aggregation‐Induced Emission Luminogens via Formation of Dimeric Borate Crystals with Acid Additives

Abstract2‐Quinolyl benzodiazaborine (DAB) was synthesized and its conversion to a borate species was investigated. Addition of carboxylic acids and hydrogen fluoride led to facile formation of a stable borate derivative, whose structure was unambiguously characterized by single crystal X‐ray diffraction analysis. The borates show intense aggregation‐induced emission (AIE) in crystals, which is thought to be derived from a rigid dimeric structure with intermolecular hydrogen bonding.

Luminescence properties of rare-earth-doped fluoride borate crystals

Single crystals of undoped and Ce3+, Tb3+, and Eu3+/Tb3+/Ce3+ co-doped Ba12(BO3)6[BO3][LiF4] crystals were grown from high-temperature solutions. The Ba12(BO3)6[BO3][LiF4] compound crystallizes in the structural type of barium orthoborate Ba3(BO3)2 with porous Ba12(BO3)66+ cationic framework filled with disordered anionic groups. The PL and PLE spectra of undoped and rare-earth-doped crystals were studied. The photoluminescence temperature dependences in the range of 77–300 K were recorded. The shape and position of lines in the spectra are typical of cerium, terbium, and europium ions. Luminescence lifetime constants were measured in the range of 77–300 К. It was shown that at the excitation wavelength of 300 nm and 370 nm at 300 K, Ba12(BO3)6[BO3][LiF4]:Eu3+, Tb3+, Ce3+ crystals have luminescence close to daylight with CIE chromaticity coordinates and correlated color temperature of (0.335; 0.309), 5352 K and (0.295; 0.362), 7121 K, respectively. Our results indicate that rare-earth-doped Ba12(BO3)6[BO3][LiF4] crystals can be considered a candidate for the conversion of LED emission into white light.

High-power, high-efficiency, all-fiberized-laser-pumped, 260-nm, deep-UV laser for bacterial deactivation

We report a 5.8-W deep-ultraviolet (DUV) laser obtained from frequency-quadrupling of an all-fiberized ytterbium-doped fiber (YDF) master oscillator power amplifier (MOPA). The MOPA system delivers 585 ps pulses at 1040 nm with a maximum available output power of 23.5 W for nonlinear frequency conversion. A lithium triborate (LBO) crystal and a beta barium borate (BBO) crystal are employed for second- and fourth-harmonic generation (FHG), respectively. At a repetition rate of 1.6 MHz, a maximum DUV output power of 5.8 W is obtained at 260 nm with a corresponding pulse energy of 3.6 μJ and maximum peak power of at least 6.9 kW. A 1μm-to-260nm conversion efficiency of 26.4% is achieved at a DUV output power of 5.8 W. To the best of our knowledge these results represent the highest-average-power fiberized-laser-pumped DUV laser, as well as the most efficient DUV generation based on BBO crystals to date. We further demonstrate application of the pulsed DUV laser in bacterial disinfection achieving an inactivation efficiency of 99.999% for E-coli bacteria at a DUV exposure of 7 mJ/cm2.

Review of the Yb3+:ScBO3 Laser Crystal Growth, Characterization, and Laser Applications

Passive Q-switching is an effective approach for generating pulsed lasers, owing to its compact and additional modulation-free design. However, to compare favorably with active Q-switching and multi-stage amplification, the output energy needs to be enhanced for practical applications. Kramers Ytterbium ion (Yb3+)-doped borate crystals, with their excellent energy storage capacity, have been proven to be high-potential laser gain mediums for achieving pulsed lasers with moderate and high output energy using passive Q-switching technology. In this study, the growth, characterization, and laser generation of one Yb3+-doped borate crystal, the Yb3+:ScBO3 crystal, are systematically reviewed. The continuous-wave and passive Q-switching laser characteristics are presented in detail, and the self-pulsations derived from intrinsic ground-state reabsorption are also demonstrated. The specific characteristics and experiments confirm the potential of the Yb3+:ScBO3 crystal for future pulsed laser applications with moderate or even high energy output.

Doubling of THz Radiation Frequency in Nonlinear Borate Crystals

Doubling of THz Radiation Frequency in Nonlinear Borate Crystals

Potential of Sub-THz-Wave Generation in Li2B4O7 Nonlinear Crystal at Room and Cryogenic Temperatures

Due to their high optical damage threshold, borate crystals can be used for the efficient nonlinear down-conversion of terawatt laser radiation into the terahertz (THz) frequency range of the electromagnetic spectrum. In this work, we carried out a thorough study of the terahertz optical properties of the lithium tetraborate crystal (Li2B4O7; LB4) at 295 and 77 K. Approximating the terahertz refractive index in the form of Sellmeier’s equations, we assessed the possibility of converting the radiation of widespread high-power laser sources with wavelengths of 1064 and 800 nm, as well as their second and third harmonics, into the THz range. It was found that four out of eight types of three-wave mixing processes are possible. The conditions for collinear phase matching were fulfilled only for the o − e → o type of interaction, while cooling the crystal to 77 K did not practically affect the phase-matching curves. However, a noticeable increase of birefringence in the THz range with cooling (from 0.12 to 0.16) led to an increase in the coherence length for o − o → e and e − e → e types of interaction, which are potentially attractive for the down-conversion of ultrashort laser pulses.