Qing-Ming Lu

Optical channel waveguides in Nd:YVO4 crystal produced by O+ ion implantation

In this letter, we report on optical channel waveguides in Nd:YVO4 crystals produced by photographic masking and following direct O+ ion implantation at 3.0MeV. Annealing treatments of the samples are performed to improve the waveguide stability and to reduce losses. An increase of the ordinary refractive index induced by the implantation is believed to be responsible for waveguide formation. Quasi-TM guided modes are observed, while no quasi-TE ones are detected. The optical damping coefficients are of 0.43, 0.63, and 0.54cm−1 for channel waveguides with widths of 4, 5, and 6μm, respectively. The result of modal analysis is in agreement with the experimental data.

Optical waveguide in stoichiometric lithium niobate formed by 500 keV proton implantation

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.

Waveguide formation in LiTaO3 and LiB3O5 by keV hydrogen ion implantation

Abstract Lithium tantalate (LiTaO 3 ) samples were implanted with H + ions at different energies from 250 to 350 keV using different doses. Lithium triborate (LiB 3 O 5 ) samples were implanted at 350 keV H + ions with doses from 1×10 16 to 5×10 16 ions/cm 2 in increment of 1×10 16 ions/cm 2 at room temperature. The modes in LiTaO 3 and LiB 3 O 5 samples were measured by a model 2010 prism coupler. Two or three modes were observed in most cases. The change of the refractive index depends on the energy, dose and annealing temperature. Multi-energy implantation was used to broaden the optical barrier. There is a threshold dose of around 4×10 16 ions/cm 2 for LiB 3 O 5 which is different from the case of LiTaO 3 . The preliminary results show that the waveguide formation in LiTaO 3 and LiB 3 O 5 crystals is possible by using keV H + ion implantation.

Structure and the nonlinearity of lithium triborate studied by Raman and infrared reflectivity spectroscopy

Raman and infrared measurements of the LiB 3 O 5 (LBO) crystals were completed. The experimental results shown here are more and stronger Raman lines and infrared absorption peaks, which implies that the external vibrations of the trigonal (BO 3 ) 3− and tetrahedral (BO 4 ) 5− ions, especially the former, in the six-membered boron–oxygen rings at the low wave number are strong and the internal vibrations of the (BO 4 ) 5− ions above 200 cm −1 are stronger than those of the (BO 3 ) 3− ions if compared with the Raman spectra of BaB 2 O 4 crystals. These are caused due to the slope and distortions of the B 3 O 7 rings and their BO 3 and BO 4 units in LBO, which change the structural rigidity of the crystals, intensify the long-range electrostatic force and short-range molecular force, and shorten the ultraviolet absorption edge.

Property study on nickel ion implanted planar waveguide in KTiOAsO4 crystal

Abstract The first planar waveguide in KTiOAsO 4 (KTA) crystal by nickel ion implantation is presented. The dark modes are observed and analyzed using the prism-coupling method. The refractive index profile is reconstructed by the reflectivity calculation method. A comparison of the refractive index profile is made between the as-implanted waveguide and one annealed at 240 °C for 50 min. The TRIM 98 code is carried out to simulate the implantation process, which may be helpful to understand the formation of the waveguide in KTA.

Refractive index profiles of MeV phosphor ion implanted planar waveguide in KTP

Abstract The first MeV phosphor ion implanted planar optical waveguide in KTiOPO4 (KTP) is reported. The modes in the KTP waveguide were measured by dark mode coupling method using a model 2010 prism coupler. The refractive index profile was analyzed by reflectivity calculation method (RCM) at room temperature, after treatment at 200°C for 30xa0min (in air) and 77xa0K for 150xa0min (in liquid nitrogen), respectively.

Refractive index profiles in YCa4O(BO3)3 and Nd:YCa4O(BO3)3 waveguides created by MeV He ions

Abstract YCa4O(BO3)3 (YCOB) is one of the rare-earth calcium oxyborate family of crystals. The crystal has good potential to be used for self-frequency doubling due to its excellent combination of nonlinear and laser properties. We have used MeV He+ ions to make waveguides in YCOB and Nd:YCOB (NdYCOB) crystals. The ion implantation was carried out with 2.8 MeV He+ ions at room temperature. The fluences have varied from 1.5×1016 to 5.5×1016 ions/cm2. The model 2010 prism coupler was used to measure the modes in YCOB and NdYCOB waveguides formed by MeV He+ ion implantation. The refractive index profiles are fitted based on the reflectivity calculation method. We have used TRIM98 simulation to get the range and damage profiles by MeV He+ ions in YCOB. Especially the refractive index change as a function of fluence is discussed.

The formation of double waveguides in a KTP crystal by combining ion exchange with ion implantation

Double waveguides were produced in potassium titanyl phosphate (KTiOPO4 or KTP) by ion exchange in pure RbNO3 at 340u2009°C for 45u2009min, and subsequently ion implantation with 500u2009keV O ions at a dose of 1 × 1015 ionsu2009cm−2. By the prism-coupling method the guided mode spectra as well as the refractive index profiles of the ion-exchanged sample were determined. The relative value of the refractive index distribution of the ion implanted KTP sample in the z direction was simulated, which indicates the formation of double waveguides. The field pattern of the propagation light in the waveguide was collected and studied by the end-coupling method. The near-field pattern of two planar operating waveguides was observed, one upon the other. The irradiation damage as well as the Rb distribution was analysed by means of the Rutherford backscattering spectrometry technique.

Analysis of refractive index profile in a silicon ion-implanted KTiOPO4 waveguide

Abstract The Si+ ion-implanted KTiOPO4 optical waveguide was reported. The 3.0 MeV Si+ ions at a dose of 2×1015 ions/cm2 were implanted into the KTiOPO4 crystal at room temperature to form a waveguide structure with a thickness of more than 2 μm. The prism-coupling method was carried out to measure the effective refractive indices of the waveguide dark modes. The refractive index profile was reconstructed using reflectivity calculation method (RCM). The TRIM 98 (transport of ions in matter) code was applied for simulating the process of the ion implantation, which was believed to be helpful to a better understanding of the waveguide formation.

Property studies of optical waveguide formed by MeV He+ ion implanted into Nd:NaY(WO4)2 crystal

Abstract The first planar optical waveguide was formed in neodymium sodium yttrium tungstate (Nd:NaY(WO4)2) crystal by 2.6xa0MeV He+ ion implantation at a dose of 1.5×10 16 ions/cm 2 at room temperature. The dark modes were measured using the prism-coupling method. The refractive index profiles were analyzed using the reflectivity calculation method (RCM). TRIM’98 (transport of ions in matter) code was used to simulate the damage profile in Nd:NaY(WO4)2 by 2.6xa0MeV He+ ion implantation. The fluorescence spectrum of the sample was measured.