Zhengping Wang

Shandong University, Chi-nan-shih, Shandong Sheng, China

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Publications (138)295.21 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The steady-state stimulated Raman scattering (SRS) gain with different excitation wavelengths ranging from 400 to 1100 nm of tungstate crystals, SrWO4 and BaWO4, is systematically researched. As excitation frequency is close to electronic transition frequency, molecular polarizability is not a constant, which has to be taken into account in our work. The experiment and theory agree well with each other and show that SRS gain is not only proportional to Stokes light frequency, but is also inversely proportional to biquadratic excitation frequency.
    Chinese Optics Letters 12/2014; 12(12). · 1.07 Impact Factor
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    ABSTRACT: The linear and nonlinear optical properties of TbCa4O(BO3)3 (abbreviated as TbCOB) single crystals were investigated for the first time. The refractive indices of TbCOB at several wavelengths were measured by using the minimum deviation method and the parameters of Sellmeier’s dispersion equation were determined from the experimental data. The complete set of six second-order nonlinear optical (NLO) coefficients of TbCOB single crystals were obtained using the Maker fringe (FM) technique, with the largest d32 being on the order of 1.65 pm/V. Moreover, the phase-matching (PM) configurations of second-order harmonic generation (SHG) in the principal planes were calculated, and the largest effective NLO coefficient is deff = 0.86 pm/V along (22.56°, 180°) PM direction. The SHG conversion efficiency from 1064 nm to 532 nm of 8 mm long crystal samples without AR coating along this direction was achieved 57.1% at 28.2 mW input power, and it has a small walk-off angle of 13.8 mrad. In addition, the comparison and discussion with GdCOB and YCOB were carried out.
    Optics Express 11/2014; 22(22). · 3.55 Impact Factor
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    ABSTRACT: Crystal materials with integrated functionalities are desirable for the miniaturization of future optical devices. In this paper, nonlinear optical crystals of Ca3TaGa3Si2O14 (CTGS) and Nd3+ doped CTGS (Nd:CTGS) were grown using the Czochralski pulling method and explored for self-frequency-doubling applications. Based on the refractive indexes, the optimum phase matching directions for CTGS crystals were determined for type I (38.7°, 30.0°) and type II (61.1°, 0°) orientations, with respective effective nonlinear optical coefficients on the order of 0.44 pm V−1 and 0.34 pm V−1. Self-frequency-doubling was realized in Nd:CTGS crystals [(38.7°, 30.0°) (type I)] for the first time, and 18.8 mW laser power at 533 nm was achieved.
    CrystEngComm 10/2014; · 3.88 Impact Factor
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    ABSTRACT: New nonlinear optical (NLO) crystals TmCa4O(BO3)3 (TmCOB) were grown by the Czochralski pulling method, and the anisotropy of second-harmonic-generation (SHG) properties were characterized. Based on the ratio of the peaks of the 2ω signals produced by TmCOB and that of KTP crystal samples at the low fundamental energy, the NLO tensor coefficients d12, d32, d31 and d13 were determined and found to be 0.24, 1.70, −0.55 and −0.32 pm/V, respectively. At 1064 nm, the phase-matching (PM) curves and the effective NLO coefficients (deff) in spatial distribution were evaluated. Efficient SHG was realized on a (32.5°, 180°)-cut TmCOB sample (4 × 4 × 11.8 mm3) in principal plane, by using a 1064 nm Nd:YAG pico-second laser, where the highest conversion efficiency of the single-pass light reached up to 51%, while for a (112.5°, 35.9°)-cut TmCOB sample (4 × 4 × 8 mm3) in spatial PM direction, the single-pass light reached 58%. Meanwhile, the angular noncritical phase matching (A-NCPM) wavelengths along the Y and Z principal axes were calculated and measured, and the limit of type-I PM wavelength of TmCOB was found to be 716 nm.
    Optical Materials Express 09/2014; 4(9). · 2.92 Impact Factor
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    ABSTRACT: For rapid grown DKDP crystals, homogeneity should be paid more attention than traditional grown ones because their deuterated levels will be affected more significantly by the large supersaturation, which give harmful impact on optical property as well as the related nonlinear optical applications. In this paper, from the points of deuterated level and transmittance, the homogeneity of a point-seed rapid grown DKDP crystal with sizes of 65 × 65 × 113 mm3 is investigated. The results show that the maximum discrepancy of deuterium content is 5.4%, and the ultra-violet transmittances of the dislocation zone and its surrounding areas are ~30% inferior to other regions.
    Optical Materials Express 05/2014; 4(5). · 2.92 Impact Factor
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    ABSTRACT: We report a laser-diode pumped continuous-wave (cw) and passively Q-switched eye-safe laser at about 1.42 μm with the neodymium-doped yttrium gallium garnet (Nd:YGG) crystal for the first time to our knowledge. The composite Nd:YGG crystal was developed originally. A systematic comparison of laser performance between the homogeneously doped and composite Nd:YGG crystal was made, which showed that the composite Nd:YGG manifested less thermally induced effects. Cw output power of 2.06 W was obtained with the slope efficiency of 20.7%. With a V:YAG as a saturable absorber, the passive Q-switching at 1.42 μm was gotten with the pulse width, pulse energy, and peak power of 34 ns, 46.7 μJ, and 1.4 kW, respectively. The present work should provide a potential candidate for the generation of eye-safe lasers.
    Optics Letters 03/2014; 39(6):1341-4. · 3.39 Impact Factor
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    ABSTRACT: Sapphire, garnet and vanadate crystals are the most prominent optical materials, and vanadates play important roles in optics, especially in lasers and nonlinear optics. Neodymium-doped yttrium vanadate (Nd:YVO4) is representative and available commercially. Based on Nd:YVO4, several vanadate crystals are being developed with the goal of fulfilling the need for differential applications and improvement of certain operational aspects, such as with pulsed lasers or high-power continuous-wave lasers. In recent years, some important effects, including energy enhancement, bistability of output performance, self-Raman frequency shifting, etc., and some novel applications, such as quantum optics, pulsed lasers modulated by the two-dimensional crystals, etc., have been discovered with vanadates as gain materials. In this paper, the preparation, characterization and laser applications of vanadate laser crystals at the lasing wavelength of 1 micrometer, including YVO4, GdVO4, LuVO4, GdxY1–xVO4 and LuxGd1–xVO4 (0 < x < 1) doped with Nd3+ and ytterbium (Yb3+) are systematically reviewed by highlighting the most recent research progress. Their specific properties are presented, generation mechanisms of novel physical effects are discussed, new applications are given and possible future applications proposed by focusing on some potential strengths.
    Laser & Photonics Review 03/2014; · 7.98 Impact Factor
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    ABSTRACT: Multi-wavelength emissions have been demonstrated in many disordered laser crystals. Improving the emission controllability is crucial for their practical applications. However, it is difficult because the closely adjacent laser components cannot be effectively adjusted by the traditional resonator design. In this paper, the anisotropy of laser emission in a monoclinic, disordered crystal Nd:LuYSiO<sub>5</sub> (Nd:LYSO) is reported for the first time. By selecting crystal orientation, high power laser emission with different wavelengths and polarizations were obtained. For X-cut sample, 1076 nm single-wavelength laser output reached 7.56 W, which will be a useful light source for detecting carbonyl-hemoglobin and nitrite after frequency doubling. For Y- and Z-cut samples, 1076, 1079 nm dual-wavelength laser output reached 10.3 W and 7.61 W, with parallel and orthogonal polarizations, respectively, which are convenient to be used as the generation sources of 0.78 THz wave by type-I or type-II difference frequency. The output characteristic is well explained by a theoretical analysis on the stimulated emission cross-section. The present work reveals that the intrinsic anisotropy in disordered laser crystal can be utilized to elevate the emission controllability. Accordantly, the material's application scopes can be extended.
    Optics Express 02/2014; 22(3):2228-35. · 3.55 Impact Factor
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    ABSTRACT: A 0.25 at% Nd doped La0.05Lu0.95VO4 mixed crystal was grown by the Czochralski method. The thermal properties including thermal expansion, specific heat, thermal diffusion, and thermal conductivity were systematically studied. Meanwhile the reasons for cracking of this mixed crystal were also discussed. The refractive index at wavelengths of 633 nm and 1539 nm were obtained with the prism coupling method. The polarized absorption and fluorescence spectra of the crystal were also measured at room temperature. It was found that the fluorescence lifetime of 4F3/2 manifold for Nd3+ in Nd:La0.05Lu0.95VO4 is about 90 μs. Diode-pumped continuous-wave (CW) laser operations at 1.06 μm with a- and c-cut crystals were demonstrated. For the a-cut crystal a maximum output power of 5.41 W was obtained at an incident pump power of 12.9 W. Different from the a-cut crystal, the laser spectrum of the c-cut crystal was found to be dual-wavelength.
    Journal of Crystal Growth 02/2014; 387:66–72. · 1.55 Impact Factor
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    ABSTRACT: We demonstrated the continuous-wave (cw) and pulsed optical vortex with topological charges driven by heat generated during the lasing process without introducing the astigmatism effect and reducing lasing efficiency. During the lasing process, the topological charges were changeable by the thermal-induced lens and selected by the mode-matching between the pump and oscillating beams. With a graphene sample as the saturable absorber, the pulsed optical vortex was achieved at the wavelength of 1.36 {\mu}m, which identified that graphene could be used as a pulse modulator for the generation of pulsed optical vortex. It could be believed that the thermally driven cw and pulsed optical vortex should have various promising applications based on the compact structure, changeable topological charges and specific wavelength
    Optics Letters 12/2013; 39(8). · 3.39 Impact Factor
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    ABSTRACT: Graphene saturable absorber (SA) is used as the passive Q-switcher of a 0.9-\mu m solid-state laser. When the laser medium is a Nd:La0.11Y0.89VO4 crystal, the initial transmittance of the graphene SA is 78%; at an absorbed pump power of 7.62 W, the maximum average output power, largest pulse energy, and minimum pulse width are 0.62 W, 2.58 ?J, and 84 ns, respectively. This study shows that graphene is a promising and cost-saving SA for 0.9-\mu m pulse generation.
    11/2013; 12(1).
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    ABSTRACT: Refractive indices of partially deuterated potassium dihydrogen phosphate (DKDP) crystals with 55%, 70% and 80% deuterium contents were measured by autocollimation method at 293 K between 0.254 to 1.529 μm. Dependence of refractive indices of DKDP on deuterium content show different trend in the infrared region as in uv-visible region. Dependence of n2 (the square of refractive index) on the mole fraction of deuterium shows a difference between pure KDP and partially deuterated KDP. The Sellmeier equations were obtained by the least square method. The non-critical phase matching angles calculated from the fitted formula were in good agreement with laser experiment results, by which the reliability of these Sellmeier equations was confirmed.
    AIP Advances 11/2013; 3:112114. · 1.35 Impact Factor
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    ABSTRACT: We demonstrate the optical orbital angular momentum conservation during the transfer process from subwavelength plasmonic vortex lens (PVLs) to light and the generating process of surface plasmon polaritons (SPPs). Illuminating plasmonic vortex lenses with beams carrying optical orbital angular momentum, the SP vortices with orbital angular momentum were generated and inherit the optical angular momentum of light beams and PVLs. The angular momentum of twisting SP electromagnetic field is tunable by the twisted metal/dielectric interfaces of PVLs and angular momentum of illuminating singular light. This work may open the door for several possible applications of SP vortices in subwavelength region.
    Scientific Reports 11/2013; 3:3191. · 5.08 Impact Factor
  • IEEE Photonics Technology Letters 09/2013; 25(18):1785-1788. · 2.04 Impact Factor
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    ABSTRACT: Homogeneous spectrum broadening caused by temperature increasing and inhomogeneous broadening caused by ions random replacement in Nd3+-doped LuxY1-xVO4 (x = 0, 0.26, 0.41, 0.61, 0.8 and 1) series crystals were investigated. The results revealed that random replacement had greatest influence on the Nd:Lu0.61Y0.39VO4 crystal which showed the widest inhomogeneous spectrum broadening among these crystals. With a semiconductor saturable absorber mirror (SESAM), the passively mode-locking of this series crystals was carried out under the same condition. The shortest pulse was obtained also by the Nd:Lu0.61Y0.39VO4 crystal, which indirectly manifested the widest line-width of this proportion and its excellent properties for pulse laser applications.
    Optical Materials Express 09/2013; 3(9). · 2.92 Impact Factor
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    ABSTRACT: For Nd:LaxY1−xVO4 (x = 0.11) crystal, the 4F3/2 → 4I13/2 transition property was investigated for the first time. The fluorescence peak of Nd:La0.11Y0.89VO4 crystal exhibited obvious inhomogeneous broadening comparing with that of Nd:YVO4 crystal. With laser diode array as pump source, 1.34 μm continuous-wave (CW) and active Q-switched laser operations based on 4F3/2 → 4I13/2 transition were realized. For CW laser operation, the maximum output power of 2.47, 2.13 W is obtained with slope efficiencies of 29.4%, 27.6%, and optical to optical conversion efficiency of 26.2%, 24.7%, respectively for a, c cut crystal samples. For acousto-optic (AO) Q-switched laser operation, the shortest pulse width, highest peak power and maximum pulse energy came from the a-cut sample, which were 13 ns, 2.69 kW and 35 μJ, respectively.
    Infrared Physics & Technology 09/2013; 60:66–70. · 1.36 Impact Factor
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    ABSTRACT: High-efficiency frequency conversion into the deep ultraviolet in a partially deuterated ammonium dihydrogen phosphate (ADP) crystal is reported. For a 60% deuterated ADP crystal, the spontaneous Raman scattering intensity decreased by 38% compared with that of a pristine ADP crystal. At room temperature (24°C), noncritical phase-matching fourth harmonic generation of a 1053 nm laser was realized. The angular acceptance was 55.7 mrad, and the external conversion efficiency from 526 to 263 nm reached 85.3%.
    Optics Letters 05/2013; 38(10):1679-81. · 3.39 Impact Factor
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    ABSTRACT: A study of inhomogeneous spectrum broadening in Nd3+-doped GdxY1−xVO4 (x=0, 0.37, 0.47, 0.63, and 0.83) series crystals is reported for the first time, to the best of our knowledge. Due to the random placement of the Gd and Y ions in the lattice, the spectra are inhomogeneously broadened, a result that is favorable for Q-switching and mode locking. The fluorescence lifetime and stimulated emission cross-section of the F3/24 to F11/24 and F13/24 state transitions are calculated and measured as a function of increasing x and temperature. The variation of the spectrum anisotropy is also discussed as a function of different temperature and composition values. All the results indicate that the random placement of different cations at the same lattice site is an efficient technology for the modification of emission properties that fulfill different requirements of laser applications.
    Journal of the Optical Society of America B 05/2013; 30(5):1241-. · 2.21 Impact Factor
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    ABSTRACT: In current inertial confinement fusion (ICF) facilities, KDP and DKDP crystals are the second harmonic generation (SHG) and third harmonic generation (THG) materials for the Nd:glass laser (1053 nm). Based on the trend for the development of short wavelengths for ICF driving lasers, technical solutions for fourth harmonic generation (FHG) will undoubtedly attract more and more attention. In this paper, the rapid growth of an ADP crystal and non-critical phase-matching (NCPM) FHG of a 1053-nm laser using an ADP crystal are reported. The NCPM temperature is 33.7°C. The conversion efficiency from 526 to 263 nm is 70%, and the angular acceptance range is 55.4 mrad; these results are superior to those for the DKDP crystals. This research has shown that ADP crystals will be a competitive candidate in future ICF facilities when the utilisation of high-energy, high-efficiency UV lasers at wavelengths shorter than the present 351 nm is of interest.
    Scientific Reports 04/2013; 3:1605. · 5.08 Impact Factor
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    ABSTRACT: Using multilayered graphene as the saturable absorber (SA), Nd:LYSO crystal as the laser material, we demonstrated a laser-diode (LD) pumped, dual-wavelength passively Q-switched solid-state laser. The maximum average output power is 1.8 W, the largest pulse energy and highest peak power is 11.3 μJ, 118 W, respectively. As we have known, they are the best results for passively Q-switched operation of graphene. The pulse laser is strong enough to realize extra-cavity frequency conversions. With a KTP crystal as the sum-frequency generator, the dual wavelengths are proved to be well time overlapped, which manifests the synchronous modulation to the dual-wavelength with multi-layered graphene.
    Optics Express 02/2013; 21(3):3516-3522. · 3.55 Impact Factor

Publication Stats

707 Citations
295.21 Total Impact Points

Institutions

  • 2001–2014
    • Shandong University
      • State Key Laboratory for Crystal Materials
      Chi-nan-shih, Shandong Sheng, China
  • 2004
    • Shenzhen University
      • School of Engineering & Technology
      Shenzhen, Guangdong Sheng, China