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13 Feb 2006

Volume 88, Issue 7, Articles (07xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 88, 072905 (2006); http://dx.doi.org/10.1063/1.2172744 (3 pages)

Y. L. Li and L. Q. Chen
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Resonantly-enhanced transmission through a periodic array of subwavelength apertures in heavily-doped conducting polymer films

Tatsunosuke Matsui, Z. Valy Vardeny, Amit Agrawal, Ajay Nahata, and Reghu Menon

Appl. Phys. Lett. 88, 071101 (2006); http://dx.doi.org/10.1063/1.2175482 (3 pages) | Cited 7 times

Online Publication Date: 13 February 2006

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We observed resonantly-enhanced terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF6 molecules [PPy(PF6)]. The “anomalous transmission” spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the ‘anomalous transmission’ peaks are broader in the exotic metallic PPy(PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, showing that the surface plasmon polaritons on the PPy(PF6) film surfaces have higher attenuation.
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78.66.Qn Polymers; organic compounds
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
42.70.Jk Polymers and organics
78.68.+m Optical properties of surfaces
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Third-harmonic generation in a one-dimensional photonic-crystal-based amorphous nanocavity

F. Wang, S. N. Zhu, K. F. Li, and K. W. Cheah

Appl. Phys. Lett. 88, 071102 (2006); http://dx.doi.org/10.1063/1.2175483 (3 pages) | Cited 5 times

Online Publication Date: 13 February 2006

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We report a large enhancement of third-harmonic generation in the one-dimensional dielectric photonic-crystal-based amorphous nanocavity. The enhancement took place at the frequency of defect mode and was a pure χ(3) nonlinear process. A great increase of third-harmonic intensity up to approximately five orders of magnitude was demonstrated, which was attributed to field localization in the range of nanocavity.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Qs Photonic bandgap materials

Organic nanoparticle (hyperbranched polymer)-dispersed photopolymers for volume holographic storage

Yasuo Tomita, Kouji Furushima, Koichiro Ochi, Koji Ishizu, Akihiro Tanaka, Masaaki Ozawa, Motohiko Hidaka, and Katsumi Chikama

Appl. Phys. Lett. 88, 071103 (2006); http://dx.doi.org/10.1063/1.2175485 (3 pages) | Cited 22 times

Online Publication Date: 13 February 2006

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We report on the use of hyperbranched polymers (HBPs) acting as mobile organic nanoparticles doped in methacrylate photopolymers for highly efficient volume holographic recording. Two types of reduced HBPs having the average size of 10 nm are synthesized. The diffraction efficiency near 100% in the green (532 nm) and substantive polymerization-shrinkage suppression in this photopolymer system are demonstrated. Periodic assembly of HBPs under holographic exposure is also observed.
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42.70.Jk Polymers and organics
42.70.Ln Holographic recording materials; optical storage media
42.40.Ht Hologram recording and readout methods
42.79.Vb Optical storage systems, optical disks

Statistical parameters for gloss evaluation

Kai-Erik Peiponen and Mikko Juuti

Appl. Phys. Lett. 88, 071104 (2006); http://dx.doi.org/10.1063/1.2173262 (3 pages) | Cited 11 times

Online Publication Date: 13 February 2006

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The measurement of minute changes in local gloss has not been presented in international standards due to a lack of suitable glossmeters. The development of a diffractive-element-based glossmeter (DOG) made it possible to detect local variation of gloss from planar and complex-shaped surfaces. Hence, a demand for proper statistical gloss parameters for classifying surface quality by gloss, similar to the standardized surface roughness classification, has become necessary. In this letter, we define statistical gloss parameters and utilize them as an example in the characterization of gloss from metal surface roughness standards by the DOG.
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06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
07.60.-j Optical instruments and equipment
02.50.-r Probability theory, stochastic processes, and statistics
06.20.fb Standards and calibration

Optimization scheme for the quantum efficiency of GaInN-based green-light-emitting diodes

D. Fuhrmann, C. Netzel, U. Rossow, A. Hangleiter, G. Ade, and P. Hinze

Appl. Phys. Lett. 88, 071105 (2006); http://dx.doi.org/10.1063/1.2173619 (3 pages) | Cited 28 times

Online Publication Date: 13 February 2006

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We have optimized the internal quantum efficiency (IQE) of GaInN/GaN quantum-well (QW) structures. For an emission wavelength of 460 nm, a high IQE of 73% was achieved. For a longer emission wavelength, calculations predict higher oscillator strength for thinner QWs but higher In content. We observe an improvement in IQE of almost 50% when reducing the QW width from 2.7 nm to 1.8 nm, and increasing the In content for the whole blue to green spectral region with IQE = 40% at 525 nm. The typical saturation of the output power with increasing current that occurs, particularly for green-light-emitting diodes, is extremely weak in our structures.
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85.60.Jb Light-emitting devices
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Photoleakage currents in organic thin-film transistors

Sang Mi Cho, Seung Hoon Han, Jun Hee Kim, Jin Jang, and Myung Hwan Oh

Appl. Phys. Lett. 88, 071106 (2006); http://dx.doi.org/10.1063/1.2173707 (3 pages) | Cited 10 times

Online Publication Date: 13 February 2006

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We studied the light illumination effect on the performance of pentacene organic thin-film transistors (TFTs) exhibiting a field-effect mobility of 0.7 cm2/V s, threshold voltage of −7 V and on/off current ratio of 108. The transfer characteristics of the orgnaic TFT change remarkably by illumination in the subthreshold and off-state regions because of the photogenerated carriers in the TFT channel. The minimum off current increases by 105 under the illumination of 1350 lux. The drain current increases linearly with light intensity in the region where holes are majority carriers. On the other hand, the off-state currents increase superlinearly with light intensity when electrons are majority carriers. The photoleakage current increases with illumination time at the constant temperature. The results can be explained on the basis of the trapping of carriers at the grain boundaries and significant recombination of electrons and holes when electrons are majority carrier. The holes can be trapped at the grain boundaries during illumination, reducing the potential barriers at the boundaries.
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85.30.Tv Field effect devices
85.60.Dw Photodiodes; phototransistors; photoresistors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Influence of current noise on the relaxation oscillation dynamics of semiconductor lasers

Guy Van der Sande, Miguel C. Soriano, Mirvais Yousefi, Michael Peeters, Jan Danckaert, Guy Verschaffelt, and Daan Lenstra

Appl. Phys. Lett. 88, 071107 (2006); http://dx.doi.org/10.1063/1.2176852 (3 pages) | Cited 1 time

Online Publication Date: 14 February 2006

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We find experimentally that the relaxation oscillation peak in the relative intensity noise spectrum of a semiconductor laser has a higher damping and lower frequency when we add low frequency noise to the pump current. The broadening of the relaxation oscillation peak with increasing carrier noise level is interpreted as an increase of the nonlinear gain compression with noise strength.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Mi Dynamical laser instabilities; noisy laser behavior
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Enhanced efficiency in polymer light-emitting diodes due to the improvement of charge-injection balance

Yow-Jon Lin, Wei-Yang Chou, and Shih-Ting Lin

Appl. Phys. Lett. 88, 071108 (2006); http://dx.doi.org/10.1063/1.2176856 (3 pages) | Cited 8 times

Online Publication Date: 14 February 2006

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The authors report the enhancement of efficiency of polymer light-emitting diodes (PLEDs) in the study. According to the experimental results, we find that PLEDs, fabricated on irradiated indium-tin-oxide surfaces by KrF excimer laser, with an organic layer between the cathode and the emitting layer may lead to the improvement of charge-injection balance and prevention of cathode metal quenching, resulting in a remarkable increase in external quantum efficiency.
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85.60.Jb Light-emitting devices
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Fk Semiconductors

Optical tunneling effect of localized surface plasmon: A simulation study using particle-in-cell method

Yung-Chiang Lan

Appl. Phys. Lett. 88, 071109 (2006); http://dx.doi.org/10.1063/1.2176864 (3 pages) | Cited 7 times

Online Publication Date: 14 February 2006

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Optical tunneling through thin metal films with periodic Gaussian-shaped grooves was studied using the particle-in-cell method. For a normally incident TM-polarized wave, the transmission coefficients are maximal in the localized surface plasmon (LSP) modes, which is similar to the predictions of the Drude model, but with lower transmission coefficients. The plasma-plasma interactions partially smear out the LSP modes, which has not been addressed in previous studies that involved the Drude model. Although various heating and cooling processes occur at the air-plasma interface, the temperature of the plasma only slightly affects the transmission coefficients.
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73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Photonic-crystal near-ultraviolet reflectance filters fabricated by nanoreplica molding

Nikhil Ganesh and Brian T. Cunningham

Appl. Phys. Lett. 88, 071110 (2006); http://dx.doi.org/10.1063/1.2173718 (3 pages) | Cited 18 times

Online Publication Date: 14 February 2006

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One-dimensional photonic-crystal reflectance filters operating in the near-ultraviolet wavelengths were fabricated using nanoreplica molding from a silicon surface structure “master” template, patterned using electron-beam lithography. The fabricated devices produce a narrow linewidth reflectance resonance at a wavelength of 411 nm for TM polarized illumination and a broadband reflectance characteristic between 402 and 439 nm for TE polarized illumination. The measured reflectance spectra are accurately predicted by Rigorous Coupled Wave Analysis computer simulations, which demonstrate the capability for designing similar filter performance for wavelengths <350 nm through minor adjustment of the photonic-crystal lattice period.
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42.82.Cr Fabrication techniques; lithography, pattern transfer
42.79.Ci Filters, zone plates, and polarizers
42.70.Qs Photonic bandgap materials

Observation of large parity-change-induced dispersion in triangular-lattice photonic crystal waveguides using phase sensitive techniques

Jiandong Huang, Charles M. Reinke, Aliakbar Jafarpour, Babak Momeni, Mohammad Soltani, and Ali Adibi

Appl. Phys. Lett. 88, 071111 (2006); http://dx.doi.org/10.1063/1.2174098 (3 pages) | Cited 2 times

Online Publication Date: 15 February 2006

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We experimentally studied W1 triangular-lattice photonic crystal waveguides (PCWs) fabricated on semiconductor-on-insulator substrates using phase-sensitive lock-in techniques. In addition to the improved signal-to-noise ratio for power transmission measurements, we observed two large group delay peaks at frequencies corresponding to the photonic mode gap and parity changes of Bloch modes inside the PCWs.
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42.70.Qs Photonic bandgap materials
42.79.Gn Optical waveguides and couplers

Multiple-frequency terahertz pulsed sensing of dielectric films

J. Cunningham, C. Wood, A. G. Davies, C. K. Tiang, P. Tosch, D. A. Evans, E. H. Linfield, I. C. Hunter, and M. Missous

Appl. Phys. Lett. 88, 071112 (2006); http://dx.doi.org/10.1063/1.2174101 (3 pages) | Cited 9 times

Online Publication Date: 15 February 2006

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We report on a technique for the on-chip sensing of dielectric materials in the terahertz frequency range. We show that an array of band-stop filters, excited by integrated ultrafast photoconductive switches, can be used to sense dielectric loading at a number of distinct lithographically defined locations on a chip simultaneously, each location sensing a different terahertz frequency. This technique is expected to have a range of future applications in the field of on-chip terahertz systems, such as the analysis of deoxyribonucleic acid and other molecular films.
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07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
84.40.-x Radiowave and microwave (including millimeter wave) technology
77.55.-g Dielectric thin films

Second-harmonic generation to the green and yellow using picosecond fiber pump sources and periodically poled waveguides

D. A. Chestnut, S. V. Popov, J. R. Taylor, and T. D. Roberts

Appl. Phys. Lett. 88, 071113 (2006); http://dx.doi.org/10.1063/1.2174102 (3 pages) | Cited 3 times

Online Publication Date: 15 February 2006

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Compact yellow (560 nm) and green (532 nm) picosecond pulse sources are demonstrated that utilize second-harmonic generation in periodically poled potassium titanyl phosphate waveguides. Both systems employ ytterbium-doped fiber pump sources. In the yellow case, efficient single-pass Raman scattering in 25 m of dispersion-compensating fiber was additionally used to generate the 1.12 μm pump. Raman gain could similarly be used in compact configurations to generate other pump wavelengths for use in frequency upconversion schemes.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.Wi Nonlinear waveguides
42.79.Gn Optical waveguides and couplers
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.81.Dp Propagation, scattering, and losses; solitons

Fabry–Perot effects in THz time-domain spectroscopy of plasmonic band-gap structures

J. W. Lee, M. A. Seo, D. S. Kim, S. C. Jeoung, Ch. Lienau, J. H. Kang, and Q.-Han Park

Appl. Phys. Lett. 88, 071114 (2006); http://dx.doi.org/10.1063/1.2174104 (3 pages) | Cited 27 times

Online Publication Date: 15 February 2006

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Using terahertz time-domain spectroscopy, we study transmission in one-dimensional arrays of slits fabricated on metal plates by laser machining. The enhanced peaks of zero-order transmission spectra are attributed to the combined effects of Fabry–Perot and surface plasmon resonances. Angle dependence of transmission spectra shows that the strongly surface plasmon-enhanced peaks appear when the Fabry–Perot-type resonance is located nearby in energy. This means that surface waves traveling in the horizontal direction couple with nearest Fabry–Perot resonance to generate enhanced peaks. These results are in excellent agreement with theoretical calculations.
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78.66.Bz Metals and metallic alloys
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.68.+m Optical properties of surfaces
78.70.Gq Microwave and radio-frequency interactions

Transverse magnetic mode nonreciprocal propagation in an amplifying AlGaInAs/InP optical waveguide isolator

Wouter Van Parys, Bart Moeyersoon, Dries Van Thourhout, Roel Baets, Mathias Vanwolleghem, Beatrice Dagens, Jean Decobert, Odile Le Gouezigou, Dalila Make, Reinier Vanheertum, and Liesbet Lagae

Appl. Phys. Lett. 88, 071115 (2006); http://dx.doi.org/10.1063/1.2174106 (3 pages) | Cited 27 times

Online Publication Date: 15 February 2006

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The design, fabrication, and characterization of an amplifying transverse magnetic (TM)-mode optical waveguide isolator operating at a wavelength of 1300 nm are presented. The magneto-optical Kerr effect induces nonreciprocal modal absorption in a semiconductor optical amplifier with a laterally magnetized ferromagnetic metal contact. Current injection in the active structure compensates for the loss in the forward propagation direction. Monolithic integration of this optical isolator configuration with active InP-based photonic devices is straightforward. The combination of AlGaInAs/InP active material and the metal alloy Co50Fe50 results in greatly improved performance. 99 dB/cm TM mode isolation and significantly reduced insertion loss are demonstrated.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.82.Bq Design and performance testing of integrated-optical systems

Pyramidal micromirrors for microsystems and atom chips

M. Trupke, F. Ramirez-Martinez, E. A. Curtis, J. P. Ashmore, S. Eriksson, E. A. Hinds, Z. Moktadir, C. Gollasch, M. Kraft, G. Vijaya Prakash, and J. J. Baumberg

Appl. Phys. Lett. 88, 071116 (2006); http://dx.doi.org/10.1063/1.2172412 (3 pages) | Cited 13 times

Online Publication Date: 15 February 2006

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Concave pyramids are created in the (100) surface of a silicon wafer by anisotropic etching in potassium hydroxide. High quality micromirrors are then formed by sputtering gold onto the smooth silicon (111) faces of the pyramids. These mirrors show great promise as high quality optical devices suitable for integration into micro-optoelectromechanical systems and atom chips. We have shown that structures of this shape can be used to laser-cool and hold atoms in a magneto-optical trap.
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42.79.Bh Lenses, prisms and mirrors
42.79.Wc Optical coatings
81.65.Cf Surface cleaning, etching, patterning

Near-infrared electroluminescence based on perylenediimide-doped tris(8-quinolinolato) aluminum

Teodosio Del Caño, Keisuke Hashimoto, Hiroshi Kageyama, José Antonio De Saja, Ricardo Aroca, Yutaka Ohmori, and Yasuhiko Shirota

Appl. Phys. Lett. 88, 071117 (2006); http://dx.doi.org/10.1063/1.2170427 (3 pages) | Cited 2 times

Online Publication Date: 15 February 2006

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For the purpose of exploring near-infrared emission, the photoluminescence (PL) and electro- luminescence (EL) of N,N′-bis(neopentyl)-3,4:9,10-perylenebis(dicarboximide) (BNPTCD): tris(8-quinolinolato)aluminum (Alq3) mixed films were investigated. It was found that BNPTCD:Alq3 mixed films exhibit PL in the near-infrared wavelength region and that organic light-emitting diodes using Alq3 highly doped with BNPTCD as an emitting layer exhibit near-infrared EL with a peak at 805 nm originating from BNPTCD aggregates.
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85.60.Jb Light-emitting devices

Terahertz-wave generation from quasi-phase-matched GaP for 1.55 μm pumping

Isao Tomita, Hiroyuki Suzuki, Hiroshi Ito, Hirokazu Takenouchi, Katsuhiro Ajito, Rakchanok Rungsawang, and Yuko Ueno

Appl. Phys. Lett. 88, 071118 (2006); http://dx.doi.org/10.1063/1.2174832 (3 pages) | Cited 26 times

Online Publication Date: 15 February 2006

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We have realized a terahertz (THz)-wave source employing difference frequency generation (DFG) from a quasi-phase-matched GaP stack pumped at 1.55 μm. We observed THz waves with enhanced power by quasi-phase matching (QPM) in the ⟨110⟩ direction of GaP with a ⟨111⟩ polarization direction for the incidence of two pump lights with the same propagation and polarization directions. We obtained THz-wave power proportional to the product of two pump-light powers due to DFG. We also confirmed that power peaks appeared at around 1 and 2.6 THz reflecting the first- and the third-order QPM, respectively.
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07.57.Hm Infrared, submillimeter wave, microwave, and radiowave sources
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
84.40.-x Radiowave and microwave (including millimeter wave) technology

Aberration-free negative-refractive-index lens

Jiajun Chen, Cosmin Radu, and Ashok Puri

Appl. Phys. Lett. 88, 071119 (2006); http://dx.doi.org/10.1063/1.2174087 (3 pages) | Cited 3 times

Online Publication Date: 16 February 2006

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The aberrations of a spherical lens composed of left-handed materials are studied in this letter. Five Seidel aberrations (spherical, coma, astigmatism, field curvature, and distortion) as a function of the refractive index n and shape factor q of the lens are considered. Our numerical calculations show that the negative refractive index gives much larger windows of small values of aberrations than the positive index, which will significantly enhance the flexibility for the design of an optical lens. Two possible regions with optimized aberrations are proposed: n = −1, q = −2.2 and n = −0.81 and q = 0.83.
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42.79.Bh Lenses, prisms and mirrors
42.15.Eq Optical system design
42.15.Fr Aberrations
42.70.-a Optical materials

Tunable polymeric Bragg grating filter using nanoimprint technique

Do-Hwan Kim, Won-Jun Chin, Sang-Shin Lee, Seh-Won Ahn, and Ki-Dong Lee

Appl. Phys. Lett. 88, 071120 (2006); http://dx.doi.org/10.1063/1.2177353 (3 pages) | Cited 10 times

Online Publication Date: 16 February 2006

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A tunable wavelength filter was proposed and demonstrated by using the ultraviolet nanoimprint technique. It consists of a Bragg grating in polymer waveguides and a heating electrode. The creation of the grating was substantially simplified with the introduction of a smart imprint stamp containing a waveguide pattern integrated with the grating pattern. The center wavelength of the filter was successfully tuned by taking advantage of the thermooptic effect in polymers, which was induced by supplying electrical power to the electrode. For the fabricated device, a transmission dip of ∼ 15 dB and a 3 dB bandwidth of 0.8 nm were obtained at the Bragg wavelength of ∼ 1560 nm. The achieved thermooptic tuning rate was ∼ 0.28 nm/mW, while the center wavelength was shifted from 1560 nm to 1558 nm with the electrical power consumption of 7 mW.
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42.81.Wg Other fiber-optical devices
42.79.Ci Filters, zone plates, and polarizers
42.82.Cr Fabrication techniques; lithography, pattern transfer
81.16.Nd Micro- and nanolithography
42.81.Bm Fabrication, cladding, and splicing

Anomalous temperature characteristics of single wide quantum well InGaN laser diode

T. Świetlik, G. Franssen, P. Wiśniewski, S. Krukowski, S. P. Łepkowski, L. Marona, M. Leszczyński, P. Prystawko, I. Grzegory, T. Suski, S. Porowski, P. Perlin, R. Czernecki, A. Bering-Staniszewska, and P. G. Eliseev

Appl. Phys. Lett. 88, 071121 (2006); http://dx.doi.org/10.1063/1.2177368 (3 pages) | Cited 8 times

Online Publication Date: 16 February 2006

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By using an atypically wide quantum well (95 Å) in the active layer of InGaN violet light emitting laser diode, we managed to fabricate a device characterized by very high thermal stability of the threshold current. The characteristic T0 temperature was measured to be 302 K, which is the highest reported value up to date. After thermal cycling of the device, T0 drops down to the lower value of 220 K. The very high value of T0 in our devices is accompanied by anomalous temperature behavior of the device slope efficiency. The slope efficiency improves with increasing temperature, reaches a maximum and then gradually decreases. This behavior we interpret as the competition between a regular increase of the thermal carrier escape and an improvement of carrier capture efficiency with an opposite temperature dependence. The latter mechanism we tentatively attribute to the temperature quenching of the ballistic transport related carrier leakage from the active region of the laser diode.
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42.55.Ah General laser theory
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Efficient generation of Cherenkov-type terahertz radiation from a lithium niobate crystal with a silicon prism output coupler

M. Theuer, G. Torosyan, C. Rau, R. Beigang, K. Maki, C. Otani, and K. Kawase

Appl. Phys. Lett. 88, 071122 (2006); http://dx.doi.org/10.1063/1.2177540 (3 pages) | Cited 17 times

Online Publication Date: 17 February 2006

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We report on the generation of broadband terahertz (THz) pulses using Cherenkov-type generation in magnesium oxide-doped lithium niobate (MgO:LN). The efficiency of the output coupling process of THz radiation at higher frequencies into free space is considerably increased by the use of a properly cut silicon prism. The achieved spectrum is broader compared to the normal Cherenkov-cut geometry. Due to a considerably reduced propagation length in the absorbing MgO:LN, the effective application of longer crystals is possible. Thus, the measured spectral intensity is much higher and the spectrum broader.
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07.57.Hm Infrared, submillimeter wave, microwave, and radiowave sources
78.70.Gq Microwave and radio-frequency interactions
84.40.-x Radiowave and microwave (including millimeter wave) technology

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

Feng Chen, Lei Wang, Yi Jiang, Xue-Lin Wang, Ke-Ming Wang, Gang Fu, Qing-Ming Lu, Christian E. Rüter, and Detlef Kip

Appl. Phys. Lett. 88, 071123 (2006); http://dx.doi.org/10.1063/1.2177632 (3 pages) | Cited 19 times

Online Publication Date: 17 February 2006

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In this letter, we report on optical channel waveguides in Nd:YVO4 crystals produced by photographic masking and following direct O+ ion implantation at 3.0 MeV. 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 0.54 cm−1 for channel waveguides with widths of 4, 5, and 6 μm, respectively. The result of modal analysis is in agreement with the experimental data.
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42.79.Gn Optical waveguides and couplers
61.72.up Other materials
81.40.Gh Other heat and thermomechanical treatments
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