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Timestamp: 2019-04-25 06:05:19+00:00

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Optical waveguides are fabricated by irradiation of LiTaO3 with a variety of swift heavy ions that provide increasing levels of both nuclear and electronic damage rates, including C, F and Si ions, in the energy range of 15-40 MeV. A systematic study of the role of the ion fluence has been carried out in the broad range of 1e13-2e15 at/cm2. The kinetics of damage is initially of nuclear origin for the lowest fluences and stopping powers and, then, is enhanced by the electronic excitation (for F and Si ions) in synergy with the nuclear damage. Applying suitable annealing treatments, optical propagation losses values as low as 0.1 dB have been achieved. The damage rates found in LiTaO3 have been compared with those known for the reference LiNbO3 and discussed in the context of the thermal spike model.
T. Volk and M. Wöhlecke, “Lithium Niobate, Defects, Photorefraction and Ferroelectric Switching”, Springer Series in Materials Science 115, (Springer-Verlag, Berlin 2008).
P. Günter, “Nonlinear Optical Effects and Materials”, Springer Series in Optical Science, Vol. 72, (Berlin Heidelberg New York, 2000).
G. L. Tangonan, M. K. Barnoski, J. F. Lotspeich, and A. Lee, “High optical power capabilities of Ti‐diffused LiTaO3 waveguide modulator structures,” Appl. Phys. Lett. 30(5), 238–239 (1977).
I. Dolev, A. Ganany-Padowicz, O. Gayer, A. Arie, J. Mangin, and G. Gadret, “Linear and nonlinear optical properties of MgO: LiTaO3,” Appl. Phys. B 96(2-3), 423–432 (2009).
Y. Kondo, and Y. Fujii, “Temperature Dependence of the Photorefractive Effect in Proton-Exchanged Optical Waveguides Formed on Lithium Tantalate Crystals”, Jpn. J. Appl. Phys. 34 (Part 2, No. 3B), 365–367 (1995).
K. Kitamura, Y. Furukawa, K. Niwa, V. Gopalan, and T. E. Mitchell, “Crystal growth and low coercive field 180° domain switching characteristics of stoichiometric LiTaO3,” Appl. Phys. Lett. 73(21), 3073–3075 (1998).
K. Mizuuchi, K. Yamamoto, and M. Kato, “Generation of ultraviolet light by frequency doubling of a red laser diode in a first-order periodically poled bulk LiTaO3,” Appl. Phys. Lett. 70(10), 1201–1203 (1997).
V. Ya. Shur, E. V. Nikolaeva, E. I. Shishkin, V. L. Kozhevnikov, A. P. Chernykh, K. Terabe, and K. Kitamura, “Polarization Reversal in Congruent and Stoichiometric Lithium Tantalate,” Appl. Phys. Lett. 79(19), 3146–3148 (2001).
V. Ya. Shur, A. R. Akhmatkhanov, M. A. Chuvakova, and I. S. Baturin, “Polarization Reversal and Domain Kinetics in Magnesium Doped Stoichiometric Lithium Tantalate,” Appl. Phys. Lett. 105(15), 152905 (2014).
M. Marangoni, M. Lobino, R. Ramponi, E. Cianci, and V. Foglietti, “High quality buried waveguides in stoichiometric LiTaO3 for nonlinear frequency conversion,” Opt. Express 14(1), 248–253 (2006).
A. C. Busacca, E. D’Asaro, A. Pasquazi, S. Stivala, and G. Assanto, “Ultraviolet generation in periodically poled lithium tantalate waveguides,” Appl. Phys. Lett. 93(12), 121117 (2008).
P. D. Townsend, P. J. Chandler, and L. Zhang, “Optical effects of ion implantation”. Cambridge University Press (1994).
E. Glavas, L. Zhang, P. J. Chandler, and P. D. Townsend, “Thermal stability of ion-implanted LiTaO3 and LiNbO3 optical waveguides,” Nucl. Instr. and Meth. in Phys. Res. B 32(1–4), 45–50 (1988).
V. V. Atuchin, “Causes of refractive indices changes in He-implanted LiNbO3 and LiTaO3 waveguides,” Nucl. Instr. and Meth. in Phys. Res. B 168, 498–502 (2000).
C. Mingotte, “Proton and helium implanted waveguides in pure and Nd-doped lithium tantalate,” Nucl. Instr. and Meth. in Phys. Res. B 229, 55–59 (2005).
L. Jentjens, K. Peithmann, K. Maier, H. Steigerwald, and T. Jungk, “Radiation-damage-assisted ferroelectric domain structuring in magnesium-doped lithium niobate,” Appl. Phys. B 95(3), 441–445 (2009).
M. Lilienblum, A. Ofan, A. Hoffmann, O. Gaathon, L. Vanamurthy, S. Bakhru, H. Bakhru, R. M. Osgood, and E. Soergel, “Low-voltage nanodomain writing in He-implanted lithium niobate crystals,” Appl. Phys. Lett. 96(8), 082902 (2010).
A. Ofan, M. Lilienblum, O. Gaathon, A. Sehrbrock, A. Hoffmann, S. Bakhru, H. Bakhru, S. Irsen, R. M. Osgood, and E. Soergel, “Large-area regular nanodomain patterning in He-irradiated lithium niobate crystals,” Nanotechnology 22(28), 285309 (2011).
J. Olivares, G. García, A. García-Navarro, F. Agulló-López, O. Caballero, and A. García-Cabañes, “Generation of high confinement step-like optical waveguides in LiNbO3 by swift heavy ion beam irradiation,” Appl. Phys. Lett. 86(86), 183501 (2005).
M. Jubera, J. Villarroel, A. García-Cabañes, M. Carrascosa, J. Olivares, F. Agullo-López, A. Méndez, and J. B. Ramiro, “Analysis and optimization of propagation losses in LiNbO3 optical waveguides produced by swift heavy-ion irradiation,” Appl. Phys. B 107(1), 157–162 (2012).
J. Olivares, A. García-Navarro, G. García, A. Méndez, F. Agulló-López, A. García-Cabañes, M. Carrascosa, and O. Caballero, “Nonlinear optical waveguides generated in lithium niobate by swift-ion irradiation at ultralow fluences,” Opt. Lett. 32(17), 2587–2589 (2007).
A. García-Navarro, J. Olivares, G. García, F. Agulló-López, S. García-Blanco, C. Merchant, and J. S. Aitchison, “Fabrication of optical waveguides in KGW by swift heavy ion beam irradiation,” Nucl. Instrum. Method B 249(1-2), 177–180 (2006).
J. Manzano-Santamaría, J. Olivares, A. Rivera, and F. Agulló-López, “Electronic damage in quartz (c-SiO2) by MeV ion irradiations: Potentiality for optical waveguiding applications,” Nucl. Instrum. Methods B. 272, 271–274 (2012).
A. Majkić, M. Koechlin, G. Poberaj, and P. Günter, “Optical microring resonators in fluorineimplanted lithium niobate,” Opt. Express 16(12), 8769–8779 (2008).
M. Jubera, A. García-Cabañes, J. Olivares, A. Alcázar, and M. Carrascosa, “Particle trapping and structuring on the surface of LiNbO3:Fe optical waveguides using photovoltaic fields,” Opt. Lett. 39(3), 649–652 (2014).
O. Caballero-Calero, A. García-Cabañes, M. Carrascosa, F. Agulló-López, J. Villarroel, M. Crespillo, and J. Olivares, “Periodic poling of optical waveguides produced by swift-heavy ion irradiation in LiNbO3,” Appl. Phys. B 95(3), 435–439 (2009).
J. Olivares, M. L. Crespillo, O. Caballero-Calero, M. D. Ynsa, A. García-Cabañes, M. Toulemonde, C. Trautmann, and F. Agulló-López, “Thick optical waveguides in lithium niobate induced by swift heavy ions (~10 MeV/amu) at ultralow fluences,” Opt. Express 17(26), 24175–24182 (2009).
F. Chen, “Photonic guiding structures in lithium niobate crystals produced by energetic ion beams,” J. Appl. Phys. 106(8), 081101 (2009).
M. Toulemonde, W. Assmann, C. Dufour, A. Meftah, and C. Trautmann, “Nanometric transformation of the matter by short and intense electronic excitation: Experimental data versus inelastic thermal spike model,” Nucl. Instr. and Meth. in Phys. Res. B 277, 28–39 (2012).
F. Agulló-López, A. Climent-Font, Á. Muñoz-Martín, J. Olivares, and A. Zucchiatti, “Ion beam modification of dielectric materials in the electronic excitation regime: cumulative and exciton models,” Prog. Mater. Sci. 76, 1–58 (2016).
G. Fu, X. Qin, and X. Wang, ““Optical waveguide formed in a LiTaO3 crystal by using MeV C3+ ion implantation”, Journ. of the Kor. Phys,” Society 56(4), 1364–1368 (2010).
G. Liu, R. He, S. Akhmadaliev, J. R. Vázquez de Aldana, S. Zhou, and F. Chen, “Optical waveguides in LiTaO3 crystals fabricated by swift C5+ ion irradiation,” Nucl. Instr. and Meth. in Phys. Res. B 325, 43–46 (2014).
P. Liu, Q. Huang, T. Liu, S. S. Guo, L. Zhang, Y. F. Zhou, and X. L. Wang, “Visible and near-infrared waveguide properties in LiTaO3 crystal produced by swift Ar 8+ ion irradiation,” Appl. Phys. B 108(3), 675–681 (2012).
G. Szenes, “General features of latent track formation in magnetic insulators irradiated with swift heavy ions,” Phys. Rev. B Condens. Matter 51(13), 8026–8029 (1995).
K. S. Chiang, “Construction of refractive-index profiles of planar dielectric waveguides from the distribution of effective indexes,” J. Lightwave Technol. 3(2), 385–391 (1985).
O. Peña-Rodríguez, M. L. Crespillo, P. Díaz-Nuñez, J. M. Perlado, A. Rivera, and J. Olivares, “In situ monitoring the optical properties of dielectric materials during ion irradiation,” Opt. Mater. 6(3), 734–742 (2016).
Z. Zhang, I. A. Rusakova, and W. K. Chu, “Amorphization and annealing of LiTaO3 single crystal irradiated with Ar+ ions at 77 K,” J. Appl. Phys. 91(6), 3562–3568 (2002).
N. Sellami, M. L. Crespillo, Y. Zhang, and W. J. Weber, “Two-stage synergy of electronic energy loss with defects in LiTaO3 under ion irradiation,” Mater. Res. Lett. 6(6), 339–344 (2018).
Z. Zhang, I. A. Rusakova, J. Wilson, R. Chu, and W. K. Chu, “Thermal annealing of Ar ion bombarded lithium tantalate (LiTaO3) single crystal,” Nucl. Instr. and Meth. in Phys. Res. B 127-128, 515–519 (1997).
Z. Zhang, I. A. Rusakova, and W. K. Chu, “Preservation of original single domain phase in the implanted LiTaO3 single crystal by using hot implantation,” Jpn. J. Appl. Phys. 38(7), 740–742 (1999).
Fig. 1 Electronic (Se, solid lines) and nuclear (Sn, dashed lines, multiplied by a factor 10 for clarity) stopping powers curves as a function of penetration depth, calculated from SRIM-2013, for the different ions used in this study on LiTaO3, as indicated with labels in the figure. The electronic stopping power curve for F 20 MeV ions on LiNbO3 is also included (dotted line) for comparison as discussed in the text. The Se curve labeled “F 25 MeV-45° corrected” has been prepared using the SRIM data for F 25 MeV at normal angle of incidence and then compressing the depth scale to allow for the angle projection, so as to keep considering the real linear energy density along the ion track, that is the relevant value in a thermal spike model, as discussed in the text. We also present (for comparison and discussion) the direct SRIM output for F25 MeV at 45° which shows a larger Se value than at normal incidence, due to the type of calculation that averages the total ion energy in the thinner projected irradiated layer.
Fig. 2 Measured (λ = 632.8 nm) dark modes effective refractive indices (Nm, left side) and their corresponding refractive index profiles (right side, solid lines) for the ordinary (top) and extraordinary (bottom) polarizations, for the SLT samples irradiated with F25 MeV ions at 45° incidence angle, at the fluences indicated in the figure. The dashed lines part of the refractive index profiles are just guesses that are consistent with the nuclear stopping power curves. The refractive indices corresponding to the virgin substrate (no,s and ne,s) and to the amorphous state (na = 2.035) are shown with horizontal dashed lines for reference. The depth positions for both, the maximum electronic and nuclear stopping power curves (Fig. 1), are shown with vertical dashed lines. The symbols correspond to data obtained from the optical reflectance measurement (only ordinary polarization) using the low energy ion irradiation for reference, as discussed in the text.
Fig. 3 RBS/channeling spectra measured along the c axis with H 3 MeV particles on z-cut stoichiometric LiTaO3 irradiated with F 25 MeV ions at 45° incidence angle, with several fluences indicated in the figure. The spectra of a virgin sample is also shown in both channeling and random configurations. The abscissa axis of the measured spectra (energy channel) has been converted to depth to allow for comparison with the corresponding refractive index profiles shown in Fig. 2.
Fig. 4 Measured (λ = 632.8 nm) dark modes effective refractive indices (Nm, left side) and their corresponding refractive index profiles for the ordinary polarization, for the CLT samples irradiated with F 20 MeV ions, at the fluences indicated in the figure. The depth positions for both, the maximum electronic and nuclear stopping power curves (see Fig. 1), are shown with vertical dashed lines.
Fig. 5 Measured (λ = 632.8 nm) dark modes effective refractive indices (Nm, left side) and their corresponding refractive index profiles for the ordinary polarization, for the CLT samples irradiated with C 15 MeV ions, at the fluences indicated in the figure. The depth positions for the maximum nuclear stopping power curve (see Fig. 1), is shown with vertical dashed line.
Fig. 6 Measured (λ = 632.8 nm) dark modes effective refractive indices (Nm, left side) and their corresponding refractive index profiles (right side, solid lines) for the ordinary (top) and extraordinary (bottom) polarizations, for the CLT samples irradiated with Si 40 MeV ions, at the fluences indicated in the figure. The dashed lines part of the refractive index profiles are just guess that are consistent with the nuclear stopping power curves. The depth positions for both, the maximum electronic and nuclear stopping power curves (Fig. 1), are shown with vertical dashed lines. The symbols correspond to data obtained from the optical reflectance measurement (only ordinary polarization) using the low energy ion irradiation for reference, as discussed in the text.
Fig. 7 RBS/channeling spectra measured along the c axis with H 3 MeV particles on z-cut CLT irradiated with Si 40 MeV ions, with several fluences indicated in the figure. The spectra of a virgin sample is also shown in both channeling and random configurations. The abscissa axis of the measured spectra (energy channel) has been converted to depth to allow for comparison with the corresponding refractive index profiles shown in Fig. 6.
Fig. 8 Propagation losses (for the ordinary polarization, at λ = 632.8 nm) versus annealing temperature for some of the waveguides fabricated in LiTaO3 by Fluorine and Silicon irradiation.
Table 1 Main parameters relevant for a thermal spike model for LN and LT.
Main parameters relevant for a thermal spike model for LN and LT.

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