Cesium Lithium Borate Crystal Research Articles

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.

Picosecond green and deep ultraviolet pulses generated by a high-power 100 kHz thin-disk laser.

We report on the generation of the second (515 nm) and fourth (257.5 nm) harmonics from a 100 kHz diode-pumped solid-state laser operating at a wavelength of 1030 nm which uses one Yb:YAG thin disk in the regenerative amplifier and delivers 60 W of the average output power in pulses of 4 ps duration. Thirty-five W in green light and 6 W in deep ultraviolet (DUV) were achieved. The sensitivity of the second harmonic generation efficiency toward the lithium triborate crystal temperature is demonstrated in experiment. The overall conversion efficiency from NIR to DUV of 10% was achieved. The β-barium borate and cesium lithium borate crystals were used as green to DUV convertors and compared regarding the efficiency and spectral bandwidths. The achieved output power is unique for DUV picosecond pulses.

All solid-state 1917 nm deep-UV light source by seventh harmonic generation of an 888 nm pumped, Q-switched 1342 nm Nd:YVO_4 laser with excellent beam quality

In this paper we report on the realization of a deep-UV light source using the 1.3 μm transition of neodymium as pumping wavelength. The 191.7 nm radiation was obtained by generating the seventh harmonic of a high-power Q-switched 1342 nm Nd:YVO4 laser. A cesium lithium borate crystal was used for sum frequency mixing of the sixth harmonic and the fundamental. With a total of four conversion stages, up to 240 mW were achieved, with excellent beam quality at 155 mW (M2 < 1.7) and 190 mW (M2 < 1.9).

Humidity effect on hydration of CsLiB6O10 nonlinear optical crystal: X-ray diffraction study

Cesium lithium borate crystals (CLBO) grown from melt were kept under the relative humidity of 15–77%. At RH 45% or lower, water molecules are incorporated into CLBO structure resulting in symmetry reduction from I4¯2d to I4¯ without the loss of crystal quality. At higher humidity, crystal degradation is caused by the presence of liquid water on its surface as a result of capillary condensation.

Development of a versatile high temperature top seeded solution growth unit for growing cesium lithium borate crystals

The design and fabrication of a state of the art high temperature top seeded solution growth (HTTSSG) unit with seed and crucible rotation options is discussed. Crystals from solid solutions of high viscosity could be grown using the setup. The fabricated setup is used to grow high optical quality single crystals of cesium lithium borate with dimensions 50x40x40 mm(3) for frequency conversion of ir to UV laser through harmonic generation.

Growth and characterization of large CLBO crystals

A high optical quality Cesium lithium borate (CLBO) crystal with dimensions of 146×132×118 mm was grown by the Kyropoulos method. The 4th harmonic generation of a frequency doubled Nd:YAG laser, from 532 to 266 nm, was carried out with a CLBO crystal doubler, and an average output power of 28.4 W was achieved at 266 nm. Polished surfaces were etched to reveal the cracking mechanism of CLBO crystals. Through observation and comparison of the surface etching patterns, it is proved that CLBO crystals crack under chemical attack by water molecules penetrating from the (1 0 0) and (0 1 0) crystallographic planes.

Absolute non-linear optical coefficients measurements of CsLiB6O10 single crystals by second harmonic generation

Abstract We present absolute measurements of the effective non-linear optical coefficients d eff of cesium lithium borate crystals (CsLiB 6 O 10 , CLBO) by second harmonic generation using a continuous Nd-YAG laser source. The experiments were carried out at room temperature, on crystals cut perpendicular to type I or type II phase matching directions, with two different crystal lengths along the propagation direction. The d 36 and d 14 non-linear coefficients involved in d eff developments are deduced and are shown to be equal as it is predicted by the Kleinman symmetry. Two different compositions prepared by the Czochralski technique from melt with compositions of 1:1:6 and 1:1:5.5 molar ratios of Cs 2 O, Li 2 O and B 2 O 3 are comparatively studied.

Effect of melt composition on the electrical conductivity and IR absorption of CsLiB6O10 crystals

AbstractThe dc conductivity of cesium lithium borate crystals grown from different melt composition has been studied in the 50 – 750 °C range. The temperature dependence of the electrical conductivity followed the Arrhenius law in most cases. The anisotropy of the electrical conductivity of crystals was rather small. The vibrational modes of water molecules present in the crystals were detected by infrared absorption technique. It was found that the intensity of the two OH stretching vibrational bands depends on the thermal history of the crystals, and, beside the two main water bands, some additional weak lines appear at –185 °C in the crystals with low Cs/B ratio.

Generation of ultraviolet radiation with wide angular tolerance in cesium lithium borate crystal

Tangential phase-matching has been realised in cesium lithium borate (CLBO) crystal for the first time for the generation of fourth harmonic (266 nm) of Nd:YAG and third harmonic (226.7 nm) of a dye laser radiation by second harmonic generation and sum-frequency mixing with the angular tolerance as large as 22 mrad and 21 mrad respectively, over one of the interacting beams. An energy conversion efficiency of 15% for fourth harmonic generation is obtained with a 5.5 mm thick crystal and with the average pump powers only 170 and 70 mW. A set of Sellmeier dispersion equations for the CLBO crystal have also been formulated.

Fourth-harmonic generation of picosecond glass laser pulses with cesium lithium borate crystals

We report the fourth-harmonic generation of 1.5 ps, 1.053 μm glass laser pulses, where group velocity mismatch plays a significant role, at intensities up to 100 GW/cm2 using newly developed crystal, cesium lithium borate (CsLiB6O10). Type-I doubler and type-I quadrupler were used in the fourth harmonic generation experimental scheme. Energy conversion efficiencies of 24% and 53% have been achieved for frequency quadrupling and doubling of the fundamental glass laser pulses, respectively.