Ke-Ming Wang

Shandong University, Jinan, Shandong Sheng, China

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Publications (155)274.84 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The annealing behavior of 400 keV Er ions implanted in silicon-on-insulator samples is investigated by Rutherford backscattering spectrometry. It is found that the SiO2/Si(Er)/SiO2 heterostructure is formed after annealing in O2 and N2 atmospheres successively at 1000 °C. Only a small portion of the Er atoms segregated to the surface of the SOI sample. For the SOI sample co-implanted with Er and O ions, there is no evident out-diffusion of Er atoms to the SOI surface after annealing in a N2 atmosphere at 1000 °C and highly Er and SiOx doped Si is realized.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 05/2012; 278:1–3. · 1.19 Impact Factor
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    ABSTRACT: By directly simulating Maxwell's equations via the finite-difference time-domain (FDTD) method, we numerically demonstrate the possibility of achieving high-efficiency second harmonic generation (SHG) in a structure consisting of a microscale doubly-resonant ring resonator side-coupled to two adjacent waveguides. We find that ≳ 94% conversion efficiency can be attained at telecom wavelengths, for incident powers in the milliwatts, and for reasonably large bandwidths (Q ∼ 1000s). We demonstrate that in this high efficiency regime, the system also exhibits limit-cycle or bistable behavior for light incident above a threshold power. Our numerical results agree to within a few percent with the predictions of a simple but rigorous coupled-mode theory framework.
    Optics Express 03/2012; 20(7):7526-43. · 3.55 Impact Factor
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    ABSTRACT: We report on the formation and the optical properties of the planar and ridge optical waveguides in rutile TiO₂ crystal by He+ ion implantation combined with micro-fabrication technologies. Planar optical waveguides in TiO₂ are fabricated by high-energy (2.8 MeV) He+-ion implantation with a dose of 3 × 10¹⁶ ions/cm² and triple low energies (450, 500, 550) keV He+-ion implantation with all fluences of 2 × 10¹⁶ ions/cm² at room temperature. The guided modes were measured by a modal 2010 prism coupler at wavelength of 1539 nm. There are damage profiles in ion-implanted waveguides by Rutherford backscattering (RBS)/channeling measurements. The refractive-index profile of the 2.8 MeV He+-implanted waveguide was analyzed based on RCM (Reflected Calculation Method). Also ridge waveguides were fabricated by femtosecond laser ablation on 2.8 MeV ion implanted planar waveguide and Ar ion beam etching on the basis of triple keV ion implanted planar waveguide, separately. The loss of the ridge waveguide was estimated. The measured near-field intensity distributions of the planar and ridge modes are all shown.
    Optics Express 03/2012; 20(6):6712-9. · 3.55 Impact Factor
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    ABSTRACT: We fabricated a single-mode planar waveguide in z-cut Nd:YVO(4) by multienergy He ion implantation in total fluence of 4.5×10(16) ions/cm(2) at room temperature and investigated optical properties of Nd:YVO(4) before and after He ion implantation by measuring transmission, confocal microluminescence, and confocal Raman spectra. Absorption bands and the photoluminescence features of the bulk Nd:YVO(4) crystal have been preserved after He ion implantation. In Raman spectra, most of the peak positions and peak widths had no obvious change before and after He ion implantation. The guiding mode and near-field image in the waveguide were measured by the prism coupling method and end-face coupling method, respectively. We investigated the damage behavior of a Nd:YVO(4) waveguide after implantation, annealing treatment by the Rutherford backscattering/channeling technique. The minimum yield of the virgin z-cut Nd:YVO(4) was 1.98%, which increased to 4.73% after He ion implantation and decreased to 3.20% after annealing at 600 K for 30 minutes.
    Applied Optics 07/2011; 50(21):3865-70. · 1.69 Impact Factor
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    ABSTRACT: 200 keV Hg and 1000 keV Xe ions were implanted into LiNbO3 and KTiOPO4 at a tilted angle. The depth distributions of Hg and Xe ions in LiNbO3 and KTiOPO4 were measured by Rutherford backscattering of MeV He ions. The experimental ion distributions are compared with the transport of ions in matter (TRIM'89) simulation. The result shows a slight difference in the peak position between the experimental and theoretical ion distribution, but the form of the experimental ion distribution is found to be in agreement with the theoretical one predicted by TRIM'89 except for a different width in the case of LiNbO3. The FWHM (full width at half maximum) of the experimental ion distribution is larger than the theoretical one given by TRIM'89 in the case of KTiOPO4. The lateral spreads obtained are compared using different calculation procedures.
    Canadian Journal of Physics 02/2011; 72:550-553. · 0.90 Impact Factor
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    ABSTRACT: We report, for the first time to our knowledge, the formation of single mode planar waveguide in z-cut YVO4 by 400keV, 500keV He ion implantation in fluence of 3×1016ions/cm2 at room temperature or at liquid nitrogen temperature (77K). We investigated annealing behavior of the guiding mode and near-field image in the waveguide by prism-coupling method and end-face coupling method respectively. We found that the effective refractive index of the TE0 mode was different before and after annealing for the samples implanted at room temperature, while, annealing had nearly no influence on the effective refractive index of the TE0 mode of the samples implanted at liquid nitrogen temperature (77K). After annealing at 600K for 1h, no guiding mode was observed in the sample implanted by 400keV He ion in fluence of 3×1016ions/cm2 at room temperature. The Rutherford backscattering/channeling technique was used to investigate the damage reduction after annealing treatments. The minimum yield of the implanted, annealed sample was 5.43%. We reconstructed the refractive index profiles in the waveguide under different condition by applying intensity calculation method.
    Optical Materials 01/2011; 33(3):424-427. · 2.08 Impact Factor
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    ABSTRACT: We report on the fabrication of planar and ridge waveguides in lithium niobate by proton exchange combined with oxygen ion implantation. The implanted energy ranges from 600 to 1400 keV with a dose of 1 x 10(15) ions/cm(2). The modes in proton exchanged waveguide can be modulated by O ion implantation. There are different damage profiles in proton-exchanged and ion-implanted waveguides in Rutherford backscattering/channeling spectra. The refractive index profile in single-mode waveguide in lithium niobate has been obtained based on Intensity Calculation Method. Also ridge waveguide was fabricated on the basis of planar waveguide by Ar ion beam etching. The measured near-field intensity distributions of the ridge waveguide modes show a reasonable agreement with the simulated ones. The estimated propagation loss was approximately 2.2 dB/cm.
    Optics Express 07/2010; 18(15):15609-17. · 3.55 Impact Factor
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    ABSTRACT: We reported on the annealing features of the RbTiOPO4 planar waveguides fabricated by 6.0 MeV C3+ ion implantation. The thermal stability of the ion-implanted RbTiOPO4 waveguide was investigated by annealing at different temperatures ranging from 260 degrees C to 650 degrees C. Results revealed that when temperatures are higher than 550 degrees C, annealing caused the refractive indices of both ny and nz a saturation behavior. An increase of the ny refractive index in waveguide region was observed after proper annealing. The low loss planar mono-mode waveguides have been achieved in RbTiOPO4 crystals by applying appropriate ion implantation and annealing conditions.
    Optics Express 04/2009; 17(7):5069-74. · 3.55 Impact Factor
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    ABSTRACT: We reported on, to our knowledge the first time, the channel waveguide formation in KTiOPO<sub>4</sub> crystal by the implantation of protons with a special designed photoresist mask. The 2-D refractive index profile was constructed according to the measured dark-mode spectroscopy (for longitudinally planar configuration) as well as the shape of the channel waveguide cross section. Based on this index distribution, the modal profile was calculated through a numerical simulation, which showed reasonable agreement with the near-field light intensity distribution of the guided mode that was obtained by an end-coupling method. After annealing at 200deg C for 30 min in air, propagation loss of the channel waveguides was determined to be as low as ~2.9 dB/cm at wavelength of 632.8 nm.
    Journal of Lightwave Technology 06/2008; 26(10):1304-1308. · 2.56 Impact Factor
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    ABSTRACT: Cs+-K+ ion exchanges are performed on z-cut KTiOPO4 crystals with chromium coating covered. The temperature of ion exchange is 430°C, and the time range from 15min to 30 min. The dark mode spectra of the samples are measured by the prism coupling method. The channel structures on the samples are observed by a microscope and the near field pattern of the channel waveguides are measured by the end-fire coupling method. The refractive index of the samples increases and the increments at surface are modulated due to the existence of Cr film. In the region covered by Cr film, the refractive index of the samples at the surface increases dramatically in a shallow layer. The results of energy dispersive x-ray spectra indicate that in the region covered with Cr film, Cr ions participate in the ion exchange process, and enhance the refractive index. The results may provide a possibility that achieves index enhancement and Cr doping synchronically.
    Chinese Physics Letters 06/2008; 25(6):2281-2284. · 0.92 Impact Factor
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    ABSTRACT: Nd-doped KGd ( WO <sub>4</sub>)<sub>2</sub> laser crystals are implanted by either He <sup>+</sup> [at energies of (1.9+2.0+2.1) MeV and fluences of (3.24+3.24+5.4)×10<sup>15</sup> cm <sup>-2</sup> ] or C <sup>3+</sup> ions (at an energy of 6.0 MeV and a dose of 1.0×10<sup>15</sup> cm <sup>-2</sup> ). The two implantations induce diverse refractive index modifications for waveguide construction in the near surface regions, which implies different formation mechanisms between the He <sup>+</sup> and C <sup>3+</sup> ion implanted waveguides. The surface region of the He <sup>+</sup> implanted sample remains crystalline, while an optically isotropic layer with a large refractive index decrease is generated at the surface of the C <sup>3+</sup> ion implanted crystal. The results show that the implantation of C <sup>3+</sup> ions through electron excitations is considered to be responsible for the heavy lattice damage during the trajectory of the incident ions inside the substrate, creating an amorphouslike layer with a thickness of ∼3 μ m , whereas the nuclear energy deposition mechanism is dominant for a typical barrier confined waveguide construction in the case of He <sup>+</sup> ion implantation.
    Journal of Applied Physics 05/2008; · 2.21 Impact Factor
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    ABSTRACT: We report optical planar waveguide formation in vanadate laser crystals YbVO(4) by oxygen ion implantation at an energy of 3.0 MeV and doses from 5 x 10(13) to 2 x 10(15) ions/cm(2) at room temperature. Positive changes of the ordinary refractive indices occur in the implanted regions, which define a waveguide structure in the near surface. The relationship between refractive index changes and doses is presented. Waveguide modes were measured at wavelengths of 633 and 1539 nm, respectively. The magnified field pattern of the propagation light in the annealed waveguide was captured and studied by an end-coupling method. The refractive index profiles were reconstructed by the reflectivity calculation method.
    Applied Optics 04/2008; 47(8):1117-21. · 1.69 Impact Factor
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    ABSTRACT: Non-leaky planar waveguide structure has been fabricated in x-cut BiB3O6 crystal by 6MeV C3+ ion implantation at a dose of 1×1014ions/cm2. The effective refractive indices of the waveguide are measured at a wavelength of 632.8nm. We perform a computer code based on the finite difference method to reconstruct the refractive index profiles of nx and ny of this waveguide. The beam propagation method is used to calculate the electric and magnetic field profiles in the waveguide region from the reconstructed refractive index profiles. Our simulated data show that the refractive index increased waveguide layer can confine the mode completely.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 03/2008; 266(6):899-903. · 1.19 Impact Factor
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    ABSTRACT: We report on Nd <sup>3+</sup>: Mg O : Li Nb O <sub>3</sub> active planar waveguides produced by 3 MeV carbon ion implantation at dose of 7.5×10<sup>14</sup> cm <sup>-2</sup> . The extraordinary refractive index of the sample surface experiences positive alternations after the implantation and subsequent thermal annealing treatment, constructing enhanced-well confined waveguide structures. The propagation loss of the waveguide is 1–2 dB / cm , which means acceptable quality for further guide-wave applications. The microluminescence spectra of the waveguide show fairly good potentials for laser action at 929 and 1085 nm .
    Applied Physics Letters 02/2008; · 3.52 Impact Factor
  • Journal of The Korean Physical Society - J KOREAN PHYS SOC. 01/2008; 52(11).
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    ABSTRACT: We report on the optical planar waveguides formation and modal characterization in β-BaB2O4 crystals by Ni2+ ion implantation at energy of 3.0MeV and doses of ∼1014ions/cm2. The prism coupling method was used to investigate the dark-mode property at wavelengths of 633nm and 1539nm, respectively. The refractive index profiles of the waveguides with different doses were reconstructed by an effective refractive index method based on the reflectivity calculation method (RCM). The modal analysis indicates that the fields of TM modes can be well restricted in the guiding region, which means the formation of non-leaky waveguide in the crystal.
    Applied Surface Science 01/2008; 254(16):5095-5099. · 2.54 Impact Factor
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    ABSTRACT: We report on the fabrication of planar waveguide in stoichiometric lithium niobate by 500 keV proton implantation with a dose of 1x10(17) ions/cm(2). The formation of n(e) enhancement planar waveguide in the crystal was disclosed by the dark mode spectra and the subsequent endface coupling measurement. The absorption spectra show that the postannealing treatments above 400 masculineC temperature can remove the color centers induced by implantation efficiently. The propagation loss and near-field profiles of the planar waveguide were obtained with an end-face coupling system.
    Optics Express 01/2008; 15(25):16880-5. · 3.55 Impact Factor
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    ABSTRACT: We report on the optical planar waveguide formation and modal characterization in Nd:LuVO4 crystals by triple-energy O3+-ion implantation at energies of 2.4, 3.0, and 3.6 MeV and doses of 1.4, 1.4, and 3.1×1014 ions/cm2, respectively. The prism-coupling method is used to investigate the dark-mode property at a wavelength of 633 nm. The refractive index profiles of the waveguide are reconstructed by the reflectivity calculation method (RCM). The modal analysis shows that the fields of TE modes are well restricted in the guiding region, which indicates the formation of non-leaky waveguide in the crystal.
    Physica B Condensed Matter 01/2008; 403(4):679-683. · 1.28 Impact Factor
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    ABSTRACT: Monomode KTiOPO4 waveguide was formed by ion implantation with 500 keV O+ ions at a dose of 1×1015 ions cm-2 and the following ion exchange in pure RbNO3 at 340 °C for 45 min. Results indicate that it is an effective method to modulate the waveguide modes by combining ion exchange with ion implantation. Positive changes in both nx and ny refractive indices occur in the waveguide region. Continuous and homogenous field pattern of the propagation light in the waveguide was collected and studied using the end-coupling method. The irradiation damage as well as the Rb distribution was analyzed by means of the Rutherford backscattering spectrometry technique. The concentration profiles of Rb and K in KTiOPO4 were measured by the time of flight secondary ion mass spectrometry. Results show that the lattice damages formed by ion implantation act as a diffusion barrier, which stop the Rb ion and K ion exchange in the deeper depth.
    Journal of Applied Physics 01/2008; 104. · 2.21 Impact Factor
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    ABSTRACT: This paper reports on the fabrication and characterization of a ridge optical waveguide in an Er3+/Yb3+ co-doped phosphate glass. The He+ ion implantation (at energy of 2.8 MeV) is first applied onto the sample to produce a planar waveguide substrate, and then Ar+ ion beam etching (at energy of 500 eV) is carried out to construct rib stripes on the sample surface that has been deposited by a specially designed photoresist mask. According to a reconstructed refractive index profile of the waveguide cross section, the modal distribution of the waveguide is simulated by applying a computer code based on the beam propagation method, which shows reasonable agreement with the experimentally observed waveguide mode by using the end-face coupling method. Simulation of the incident He ions at 2.8 MeV penetrating into the Er3+/Yb3+ co-doped phosphate glass substrate is also performed to provide helpful information on waveguide formation.
    Journal of Physics D Applied Physics 10/2007; 40(21):6545. · 2.53 Impact Factor

Publication Stats

667 Citations
274.84 Total Impact Points

Institutions

  • 1987–2012
    • Shandong University
      • • State Key Laboratory for Crystal Materials
      • • Department of Physics
      • • School of Physics and Microelectronics
      • • Institute for Crystal Materials
      Jinan, Shandong Sheng, China
  • 2002
    • The Hong Kong University of Science and Technology
      • Department of Physics
      Chiu-lung, Kowloon City, Hong Kong
  • 1994–2002
    • Peking University
      • • Department of Technical Physics
      • • Department of Physics
      Beijing, Beijing Shi, China
  • 2000
    • Universität Osnabrück
      Osnabrück, Lower Saxony, Germany
  • 1993
    • Northeast Institute of Geography and Agroecology
      • Institute of Physics
      Beijing, Beijing Shi, China
  • 1992
    • Beijing University of Technology
      Peping, Beijing, China