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1.
Sum-frequency generation in -BaB2O4 has been studied by mixing the unpolarized output of an excimer laser pumped dye laser with its second harmonic. The shortest wavelength obtained at 95 K is 195.3 nm. A lower limit of 194.4±0.2 nm at the temperature of liquid helium can be expected. 相似文献
2.
《Optics Communications》1987,62(3):197-200
The optical characteristics of a new nonlinear crystal β-BaB2O4, including the group-velocity dispersion and the nonlinear coefficient in the femtosecond region, are investigated through the second-harmonic generation (SGH). The performances of β-BaB2O4 relative to KDP are evaluated from both calculations and measurements. From the measurements using the crystals with different thicknesses, the influence of the group-velocity mismatch of β-BaB2O4 on the broadening of the correlation width is revealed, and is found to be smaller than that of KDP. Overall performance of the SHG conversion efficiency of β-BaB2O4 including all affecting factors is evaluated to show higher values by a factor of 10 to 102 than that of KDP depending on operating conditions. 相似文献
3.
A -BaB2O4 (BBO) crystal is used to generate UV-light tunable in the range 230–303 nm by frequency doubling of an excimer-laser-pumped dye laser. This interval can be covered by a series of continuous scans of 0.25 nm (in the UV). During each scan the -BaB2O4 phase-matching angle is synchronized with the rotation of grating and etalon in the dye laser. The bandwidth of the frequency-doubled light is about 2 or 4 GHz depending on the dye laser etalon. The application is illustrated by a section of the one-photon excitation spectrum of Li2 Rydberg molecules. 相似文献
4.
An Electron Paramagnetic Resonance (EPR) study of Nd3? ions in single crystals of the low-temperature phase of barium borate (β-BaB2O4 or BBO) is presented. The EPR spectra show the existence of a minimum of three different Nd3? centres. The g-matrices for three of the centres have been determined from the analysis of the angular dependencies of the spectrum in two planes of the crystal. This study allows us to conclude that neodymium is incorporated in the low-symmetry Ba2? site. Possible reasons for the appearance of various Nd3? centres are discussed. 相似文献
5.
M. Watanabe K. Hayasaka H. Imajo J. Umezu S. Urabe 《Applied physics. B, Lasers and optics》1991,53(1):11-13
Continuous-wave coherent radiation tunable in the wavelength range 190.8–196.1 nm has been generated by sum-frequency generation in -BaB2O4. The fundamental beams were supplied by a Ti:Al2O3 laser and a frequency-doubled argon-ion laser. 相似文献
6.
The type-II phase-matched third-harmonic light generation in a -BaB2O4 crystal is studied experimentally. A passively mode-locked Nd: phosphate glass laser is used as a pump source. At a pump pulse peak intensity ofI
10=5×1010W/cm2 a third-harmonic conversion efficiency of a percent is obtained. A theoretical discussion of phase-matched third-harmonic generation in crystals of the symmetry group of -BaB2O4 (trigonal class 3) is given. The effective nonlinear susceptibility eff for type-II phase-matching is determined.On leave from the Shanghai Institute of Optics and Fine Mechanics, Academia Sinica, Shanghai, P.R. China 相似文献
7.
The spontaneous emission spectrum from a four-level atom in a double-band photonic crystal has been investigated.We use the model which assumes three atomic transitions. One of the transitions interacts with the free vacuum modes,and the other two transitions couple to the modes of the isotropic photonic band gap (PBG), the anisotropic PBG and another free vacuum. The effects of the fine structure of the lower levels on the spontaneous emission spectrum of an atom are investigated in detail in the three cases. New features of four (two) transparencies with two (one) spontaneous emission peaks, resulting from the fine structure of the lower levels of an atom, are predicted in the case of isotropic PBG modes. 相似文献
8.
Experiment study of wavelength conversion in a dispersion-flattened photonic crystal fiber 总被引:1,自引:0,他引:1
《中国光学快报(英文版)》2007,(9)
Wavelength conversion based on four-wave mixing(FWM)has been demonstrated using a 40-m dispersion flattened highly nonlinear photonic crystal fiber(HNL-PCF).A conversion efficiency of-26 dB for a pump power of 19.5 dBm and a conversion bandwidth of 28 nm have been obtained,which are limited by the continuous wave(CW)laser wavelength range and tunability of optical band pass filters(OBPFs). 相似文献
9.
《Journal of Physics and Chemistry of Solids》2003,64(7):1179-1184
A continuous-wave (CW) YAG laser (power: 0.75–0.9 J/s, irradiation time: 15 s–15 min) with a wavelength of 1064 nm is irradiated to 11.1Sm2O3·44.4BaO·44.4B2O3 glass, and the formation of β-BaB2O4 (β-BBO) crystalline dots with a diameter of 30–150 μm is confirmed from micro-Raman spectra. β-BBO crystals with around 200 μm length grow towards the interior of the glass. The incorporation of Sm3+ into β-BBO crystalline dots is suggested from micro-Raman and fluorescence spectra. The second harmonic generation is detected from the array (10×10=100 dots) of β-BBO crystalline dots, indicating that each crystalline dot formed by YAG laser irradiation is a nonlinear optical crystal. CW YAG laser irradiation to glass with Sm3+ ions is a nice technique for a spatially controlled crystal growth. 相似文献
10.
The two models of three-level (one upper level and two lower levels, or two upper levels and one lower level) atom embedded in a double-band photonic crystal are adopted. The atomic transitions from the upper levels to the lower levels are assumed to be coupled by the same reservoir which are respectively the isotropic photonic band gap (PBG) modes, the anisotropic PBG modes and the free vacuum modes. The effects of the fine structure of the atomic ground state levels in the model with one upper level and two lower levels, and the quantum interferences in the model with two upper levels and one lower level on the spontaneous emission spectrum of an atom are investigated in detail. Most interestingly, it is shown that new spontaneous emission lines are produced from the fine splitting of atomic ground state levels in the isotropic PBG case. The quantum interferences induce additional narrow spontaneous lines near the transition from the empty upper level to the lower level. 相似文献
11.
Ch. Venkata Reddy Ch. Rama Krishna T. Raghavendra Rao D.V. Sathish P.S. Rao R.V.S.S.N. Ravikumar 《Journal of luminescence》2012,132(9):2325-2329
Co2+ and Ni2+ ions doped β-BaB2O4 nanopowders have been prepared by co-precipitation method and their structural properties are studied by spectroscopic techniques. Powder XRD data reveals that the crystal structure belongs to monoclinic and the average crystallite size is calculated. Optical absorption spectra data reveal octahedral site symmetry for Co2+ and Ni2+ ions. Crystal field (Dq) and inter-electron repulsion (B and C) parameters are evaluated for Co2+ doped β-BaB2O4 nanopowders as Dq=960, B=900 and C=3850 cm?1 and for Ni2+ doped β-BaB2O4 nanopowders, Dq=900, B=850 and C=3500 cm?1. FT-IR spectra showed the characteristic vibrational bands related to BO3 and BO4 molecules. Photoluminescence spectra contain the emission bands in ultraviolet and blue regions. 相似文献
12.
AA Ionin IO Kinyaevskiy YM Klimachev AA Kotkov AY Kozlov YM Andreev GV Lanskii AV Shaiduko AV Soluyanov 《Optics letters》2012,37(14):2838-2840
Collinear cascaded mid-IR frequency conversion in a single nonlinear optical crystal was accomplished. Concurrent collinear generation of the sum frequency of multiline fundamental band carbon monoxide laser radiation as a first frequency conversion cascade resulted in collinear difference frequency generation within the 4.3 to 4.9 μm spectral range when mixing this sum frequency radiation with the fundamental one as the second cascade in the same ZnGeP(2) nonlinear optical crystal. 相似文献
13.
T. Tsuboi 《Applied physics. B, Lasers and optics》2000,70(2):175-177
Intense, directional, and narrow-bandwidth 1130-nm emission was generated from LiF crystal at room temperature by the pumping
with radiation in the wavelength region of the absorption band of the F2
− color center. The emission was observed by the pumping with radiation of pulse energy above 5 mJ, and the divergence angle
of the beam was about 16 mrad. This emission is attributed to the amplified spontaneous emission by the F2
− center.
Received: 8 April 1999 / Revised version: 18 May 1999 / Published online: 16 September 1999 相似文献
14.
Suppressing the preferential o-polarization oscillation in a high power Nd:YVO4 laser with wedge laser crystal
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We observe the phenomenon of priority oscillation of the unexpected a-polarization in high-power Nd:YVO4 ring laser. The severe thermal lens of the a-polarized lasing, compared with the n-polarized lasing, is the only reason for the phenomenon. By designing a wedge Nd:YVO4 crystal as the gain medium, the unexpected a-polarization is completely suppressed in the entire range of pump powers, and the polarization stability of the expected zc-polarized output is enhanced. With the output power increasing from threshold to the maximum power, no a-polarization lasing is observed. As a result, 25.3 W of stable single-frequency laser output at 532 nm is experimentally demonstrated. 相似文献
15.
We report an effect of enhanced emission of laser generated plume in gas ambi-ent.Nonreactive argon gas was used in the experiment of UV laser ablation of copper plate.The emission of Cu atoms from the plume was increased more than the times.The emission in-tensity is sensitive to the gas pressure,but in a certain region of gas pressure,the enhanced ef-fect can be controlled stably.For the emission lines from other element,Zn,in the plume,the intensities are subjected to the same factor of increasement. 相似文献
16.
M. Siebold S. Bock U. Schramm B. Xu J. L. Doualan P. Camy R. Moncorgé 《Applied physics. B, Lasers and optics》2009,97(2):327-338
Here is presented and discussed the history, the spectroscopic, the thermo-mechanical and the laser properties of the new old laser crystal Yb:CaF2, of its Sr and Ba isotypes as well as of an Yb and Na codoped compound. It will be shown that Yb:CaF2 is a very particular luminescent material, in which the laser-active center probably consists of a complex hexameric cluster, that it is the most promising Yb-doped fluoride material for large-scale, high-power and high-energy laser systems and that it can compete in several aspects with the currently used Yb-doped oxide crystals and glasses. The opportunity of operating the crystals at cryogenic temperatures and the recently achieved improvements in the field of femtosecond pulsed laser operation and high peak power laser amplification is highlighted and evaluated. 相似文献
17.
T. M. Riseman J. H. Brewer K. H. Chow W. N. Hardy R. F. Kiefl S. R. Kreitzman R. Liang A. Macfarlane P. Mendels G. D. Morris J. Rammer J. W. Schneider C. Neidermayer S. L. Lee 《Hyperfine Interactions》1994,86(1):481-487
We present transverse fieldSR measurements of the magnetic field distribution in a mosaic of single crystal YBa2Cu3O6.95 in high fields (1.9–6.5 T) applied parallel to the crystallographicc-axis. TheSR lineshapes are shown in detail and the results of fits to the lineshapes are summarized. 相似文献
18.
V. M. Vinokurov A. R. Al-Soufi A. A. Galeev N. M. Khasanova G. R. Bulka N. M. Nizamutdinov 《Applied magnetic resonance》1994,7(2-3):323-337
The expansion of the {B 2} and {B 4} tensors of the spin Hamiltonian (SH) for Mn2+ (6S-state) is performed in terms of the irreducible tensor products {V L 1 ?V L 2}2 and {V L 1 ?V L 2}4 of the crystal field (CF) tensors {V L 1} and {V L 2}. The EPR spectra of Mn2+ in the ZnSeO4·6H2O crystal are studied and the SH tensors {B 2} and {B 4} are calculated. The tensors {V 4?V 4}2 and {V 4?V 4}4 are computed using the point-charge model (PCM) of the [Zn(H2O)6] complex with the C2 symmetry and are compared with the SH tensors {B 2} and {B 4}, respectively. The correct signs of the elements and the pseudo-symmety axes of the tensors are obtained both for the {B 2} tensor and {V 4?V 4}2 and for the {B 4} tensor and {V 4?V 4}4. It is concluded that the irreducible tensor products {V 4?V 4}2 and {V 4?V 4}4 provide the predominant contribution respectively to the SH tensors {B 2} and {B 4} of Mn2+. 相似文献
19.
Suppressing the preferential σ-polarization oscillation in a high power Nd:YVO_4 laser with wedge laser crystal
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We observe the phenomenon of priority oscillation of the unexpected σ -polarization in high-power Nd:YVO 4 ring laser. The severe thermal lens of the σ -polarized lasing, compared with the π-polarized lasing, is the only reason for the phenomenon. By designing a wedge Nd:YVO 4 crystal as the gain medium, the unexpected σ -polarization is completely suppressed in the entire range of pump powers, and the polarization stability of the expected π-polarized output is enhanced. With the output power increasing from threshold to the maximum power, no σ -polarization lasing is observed. As a result, 25.3 W of stable single-frequency laser output at 532 nm is experimentally demonstrated. 相似文献
20.
A Brillouin scattering study of the behavior of hypersonic longitudinal acoustic phonons in crystalline pentacesium trihydrogen tetrasulfate Cs5H3(SO4)4 · xH2O (PCHS) and its deuterated analog Cs5D3(SO4)4 · xD2O (DPCHS) at temperatures ranging from 420 to 120 K is reported. The effect of deuteration on the crystal lattice dynamics is investigated. The differences in the behavior of hypersonic acoustic phonons in the PCHS and DPCHS crystals suggest the existence of a hydrogen isotope effect in both the high-and low-temperature phases. A possible model of the isotopic effect in the high-temperature phase is discussed. An analysis is made of the acoustic response of the PCHS and DPCHS crystals in the region of the transition to the glasslike phase. 相似文献