共查询到20条相似文献,搜索用时 15 毫秒
1.
A polymer waveguide was fabricated to amplify the evanescent optical field for biosensing. The structure of waveguide was designed to propagate a normal single mode at the input and output regions for low loss beam coupling and propagation. A sensing region was formed in the middle of the waveguide to activate the evanescent mode and to induce high birefringence by depositing a thin dielectric film with a high refractive index on a single mode waveguide. A polymer waveguide with the dimensions of 7 μm-width and 2.5 μm-thickness was fabricated by photolithography and dry-etching. The active region of the TiO2 thin film was fabricated with the dimensions of 20 mm-length, 20 nm-thickness and 2 mm-tapered tail. A polarimetric interference technique was used to evaluate the evanescent waveguide biosensor, and biomaterial such as glycerol was tested. The sensitivity of the sensor increased with increasing TiO2 film thickness. For the fabricated waveguide with a 20 nm-thick TiO2 film, the measured index change to the lead phase variation of 2π was 1.8 × 10−4. 相似文献
2.
Simiao Xiao 《Optics Communications》2009,282(13):2506-1112
One kind of electro-optic polymer assisted Mach-Zehnder optical switch based on silicon slot structure is presented in this paper. The interference arms of the switch are slot structures instead of regular single-mode waveguides. By filling electro-optic material in the void slot of the arms, direct electro-optic modulation can be introduced. Theoretical model and detailed analysis are given in this paper. The length-independent product VπL is about 74 mV cm when slot width is 100 nm, and 37 mV cm when slot width is 50 nm, when the polymer with a electro-optical coefficient of γ33 = 130 pm/V is assisted. An ultralow energy consumption of only 37 fJ/bit is achievable, and the turn-on time of the switch is less than 1.5 ps. 相似文献
3.
We report on the optical planar waveguide formation and modal characterization in Nd: GdVO4 crystals by triple oxygen ion implantation at energies of (2.4, 3.0, and 3.6 MeV) and fluences of (1.4, 1.4, and 3.1) × 1014ions/cm2. The prism-coupling method is used to investigate the dark-mode property at wavelength of 632.8 nm. The refractive index profiles of the waveguide are reconstructed by an effective refractive index, neff method. The modal analysis shows that the fields of TE modes are well restricted in the guiding region, which means the formation of nonleaky waveguide in the crystal. 相似文献
4.
Yi Jiang Chuan-Lei Jia Xue-Lin Wang Ke-Ming Wang Hong-Ji Ma 《Applied Surface Science》2006,253(5):2674-2677
A planar optical waveguide has been formed in a LiB3O5 crystal using 6.0 MeV Cu+-ions with a dose of 1 × 1015 ions/cm2 at room temperature. Possible propagating modes were measured at a wavelength of 633 nm using the prism-coupling method. The refractive index profiles of the waveguide were reconstructed by an effective refractive index method and the beam propagation method was used to investigate the properties of the propagation modes in the formed waveguide. The results suggest that the fundamental TE0 and TM0 modes may be well-confined and propagate a longer distance inside the waveguide. The implantation process was also simulated using the transport of ions in matter code (TRIM), which indicates that the nuclear energy deposition may be the main factor for the refractive index change. 相似文献
5.
Sara R. Hastings-Simon Matthias U. Staudt Pascal Baldi Wolfgang Tittel Nicolas Gisin 《Optics Communications》2006,266(2):716-719
We present measurements of the linear Stark effect on the 4I15/2 → 4I13/2 transition in an Er3+-doped proton-exchanged LiNbO3 crystalline waveguide and an Er3+-doped silicate fiber. The measurements were made using spectral hole burning techniques at temperatures below 4 K. We measured an effective Stark coefficient (Δμeχ)/(h) = 25 ± 1 kHz/V cm−1 in the crystalline waveguide and kHz/V cm−1 in the silicate fiber. These results confirm the potential of erbium-doped waveguides for quantum state storage based on controlled reversible inhomogeneous broadening. 相似文献
6.
Liquid-core/liquid-cladding integrated silicon ARROW waveguides 总被引:1,自引:0,他引:1
The fabrication and characterization of a liquid-core/liquid-cladding integrated antiresonant reflecting optical waveguide (L2-ARROW) is presented. In this waveguide, the light is confined vertically by the ARROW mechanism, whereas the lateral confinement is obtained by using liquid-core/liquid-cladding (L2 waveguides) with different refractive indexes. This approach permits to realize L2 waveguides with very low refractive index core (n ≈ 1.333) and represents a new solution to solve the difficulty to reduce the optical losses in 2D-ARROWs due to the TM polarization in lateral direction. The device has been fabricated with standard silicon technology. The results show that the optical properties can be tuned by changing the type and the flow velocity of the core and the cladding liquids. 相似文献
7.
Gurinder Pal Singh Parvinder KaurSimranpreet Kaur D.P. Singh 《Physica B: Condensed Matter》2012,407(21):4269-4273
xV2O5–xCeO2–(30−x)PbO–(70−x) B2O3 glasses are synthesized by using the melt quench technique. The number of studies such as XRD, density, molar volume, optical band gap, refractive index and FTIR spectroscopy are employed to characterize the glasses. The band gap decreases from 2.20 to 1.78 eV and density increases from 3.49 to 4.25 g/cm3. FTIR spectroscopy reveals that incorporation of V2O5 in glass network helps to convert the structural units of [BO3] into [BO4]. At higher concentration of vanadium, VO vibration of [VO5] structural units and V–O–V vibration are present. The bond ionicity of glasses increases with incorporation of V2O5 contents. 相似文献
8.
N.E. Stankova I.G. Dimitrov T.R. Stoyanchov P.A. Atanasov 《Applied Surface Science》2007,254(4):1268-1272
In this work the optical and the gas sensing properties of thick TiO2 waveguide films, produced by pulsed laser deposition, were investigated by m-line spectroscopy. The films were deposited on (0 0 1) SiO2 substrates at temperature of 100 °C. The thickness of the films was measured to be in the range from 650 to 1900 nm and the roughness increases from 5 to 14.6 nm. High quality mode spectra, consisted of thin and bright TE and TM modes, were observed in the films with thickness up to 1200 nm. All the films revealed anisotropic optical properties. Gas sensitivity of the films to CO2 was examined at room temperature on the basis of the variations of the refractive index. CO2 concentration of 3 × 104 ppm was detected, which corresponds to a refractive index variation of about 1 × 10−4. The crystal structure and the optical transmittance of the films were also presented and discussed. 相似文献
9.
D. Madhavi LathaV.G.K.M. Pisipati J. Lalitha KumariP.V. Datta Prasad 《Journal of Molecular Liquids》2011,163(1):14-19
Different thermodynamic parameters are estimated from volume expansion coefficient, α for a number of N-(p-n-alkoxybenzylidene)-p-n-butyloxyanilines, nO.O4 compounds in isotropic phase (at TIN + 5 °C) and in liquid crystalline phases. The variation of different thermodynamic parameters with the alkoxy chain length in nO.O4 series and their variation with the temperature in individual liquid crystal compounds are discussed. The parameters like available volume (Va), inter molecular free length (Lf) and molecular radius (Mr) are also computed from density, and refractive index for these nO.O4 compounds and the nature of molecular free length and molecular radius are analyzed and discussed. 相似文献
10.
A. Moses Ezhil Raj V.S. Vidhya A. Thayumanavan C. Sanjeeviraja 《Physica B: Condensed Matter》2008,403(4):544-554
Thin films of indium oxide, In2O3, were deposited by chemical spray pyrolysis technique, using aqueous alcoholic solutions of indium acetylacetonate (In-acac) precursor, on glass substrates kept at temperatures between 300 and 500 °C. The structural, optical, and electrical properties have been investigated as a function of deposition temperature, precursor concentration, carrier gas pressure, and substrate-to-nozzle distance. X-ray diffraction studies showed that the formation of nanocrystalline In2O3 films is preferentially oriented along (2 2 2) plane. The surface morphological modifications with substrate temperature were observed using scanning electron and atomic force microscopic studies. Optical transmittance behavior of the films in the visible and IR region was strongly affected by the deposition parameters. The optical band gap values observed are between 3.53 and 3.68 eV. The long wavelength limit of refractive index is 1.83. The Hall mobility is found to vary from 23 to 37 cm2/V s and carrier density is found nearly constant at about 1020 cm−3. 相似文献
11.
The effects of surface preparation and illumination on electric parameters of Au/InSb/InP(100) Schottky diode were investigated, in the later diode InSb forms a fine restructuration layer allowing to block In atoms migration to surface. In order to study the electric characteristics under illumination, we make use of an He-Ne laser of 1 mW power and 632.8 nm wavelength. The current-voltage I(VG), the capacitance-voltage C(VG) measurements were plotted and analysed. The saturation current Is, the serial resistance Rs and the mean ideality factor n are, respectively, equal to 2.03 × 10−5 A, 85 Ω, 1.7 under dark and to 3.97 × 10−5 A, 67 Ω, 1.59 under illumination. The analysis of I(VG) and C(VG) characteristics allows us to determine the mean interfacial state density Nss and the transmission coefficient θn equal, respectively, to 4.33 × 1012 eV−1 cm−2, 4.08 × 10−3 under dark and 3.79 × 1012 eV−1 cm−2 and 5.65 × 10−3 under illumination. The deep discrete donor levels presence in the semiconductor bulk under dark and under illumination are responsible for the non-linearity of the C−2(VG) characteristic. 相似文献
12.
Effect of wood properties on within-tree variation in ultrasonic wave velocity in softwood 总被引:2,自引:0,他引:2
The radial variations in the velocity of longitudinal waves propagating through Japanese cedar and Japanese cypress were experimentally investigated. In addition, the tracheid length (TL), microfibril angle (MFA), air-dried density (AD), and moisture content (MC) were measured in order to determine the effect of wood properties on velocity variations within the wood trunk. For both species, the longitudinal wave velocities measured in the longitudinal direction (VL) exhibited minimum values near the pith. For Japanese cedar, VL increased from 3600 m/s toward the bark and soon attained a constant value (=4500 m/s). On the other hand, for Japanese cypress, VL kept increasing from 4000 m/s near the pith to 4800 m/s at the bark. These radial variations in VL coincided with those in the tracheid length. VL exhibited strong correlations with TL and MFA with a significant level of (p < 0.01). These findings suggest that the TL and MFA greatly affect the radial variation in the ultrasonic wave velocity in softwood. 相似文献
13.
We report a new configuration of a reflection-type confocal scanning optical microscope system for measuring the refractive index profile of an optical waveguide. Several improvements on the earlier design are proposed; a light emitting diode at 650 nm wavelength instead of a laser diode or He-Ne laser is used as a light source for better index precision, and a simple longitudinal linear scanning and a curve fitting techniques are adapted instead of a servo control for maintaining an optical confocal arrangement. We have obtained spatial resolution of 800 nm and an index precision of 2 × 10−4. To verify the system’s capability, the refractive index profiles of a conventional multimode fiber and a home-made four-mode fiber were examined with our proposed measurement method. 相似文献
14.
We have studied Au/n-GaN Schottky barrier diodes. GaN surfaces have been prepared by cleaning in HCl and (NH4)2S prior to metal deposition. The zero-biased barrier heights and ideality factors obtained from the current-voltage characteristics differ from diode to diode, although all the samples were prepared identically. The statistical analysis for the reverse bias C-V data yielded mean value of (1.35±0.04) eV for Schottky barrier height of HCl treated sample and (1.20±0.03) eV for (NH4)2S sample, where 9 dots were considered from each cleaning method. It was found that the barrier height values obtained from the C−2-V (1.43 eV) and I-V characteristics (0.89 eV) are different from each other by 0.54 eV. The inhomogeneous barrier heights were found to be related to the effect of the high series resistance on diode parameters (Akkiliç et al., 2004) [1]. 相似文献
15.
CuIn3S5 thin films were prepared from powder by thermal evaporation under vacuum (10−6 mbar) onto glass substrates. The glass substrates were heated from 30 to 200 °C. The films were characterized for their optical properties using optical measurement techniques (transmittance and reflectance). We have determined the energy and nature of the optical transitions of films. The optical constants of the deposited films were determined in the spectral range 300-1800 nm from the analysis of transmission and reflection data. The Swanepoel envelope method was employed on the interference fringes of transmittance patterns for the determination of variation of refractive index with wavelength. Wemple-Di Domenico single oscillator model was applied to determine the optical constants such as oscillator energy E0 and dispersion energy Ed of the films deposited at different substrate temperatures. The electric free carrier susceptibility and the ratio of the carrier concentration to the effective mass were estimated according to the model of Spitzer and Fan. 相似文献
16.
Er3+-Yb3+ co-doped waveguide amplifiers fabricated using thermal two-step ion-exchange are demonstrated. K+-Na+ ion-exchange process was first carried out in pure KNO3 molten bath, and then field-assisted annealing (FAA) was used to make the buried waveguides. The effective buried depth is estimated to be ∼3.4 μm for the buried FAA waveguides. With the use of cut-back method, the fiber-to-guide coupling loss of ∼4.38 dB, the waveguide loss of ∼2.27 dB/cm, and Er3+ absorption loss ∼5.7 dB were measured for a ∼1.24-cm-long waveguide. Peak relative gain of ∼7.0 dB is obtained for a ∼1.24-cm-long waveguide. The potential for the fabrication of compact optical amplifiers operating in the range of 1520-1580 nm is also demonstrated. 相似文献
17.
Shuang-Peng Wang Chong-Xin Shan Hai Zhu Bing-Hui Li Xue-Yan Liu 《Journal of luminescence》2010,130(11):2215-2217
A phosphor-converted light-emitting diode (LED) was realized by coating BaMg2Al16O27:Eu2+·Mn2+ and (SrCaPO4)·B2O3:Eu2+·Na+ phosphors onto an n-ZnO/i-MgO/p-GaN heterojunction diode. Two emission bands at around 450 and 520 nm were observed in the phosphor-converted LED under the injection of continuous current. By analyzing the optical properties of the heterojunction diode and phosphors, it is concluded that the emission at 450 nm comes from (SrCaPO4)·B2O3:Eu2+·Na+ phosphor, while the one at 520 nm comes from BaMg2Al16O27:Eu2+·Mn2+ phosphor under the excitation of the light emitted from the n-ZnO/i-MgO/p-GaN heterojunction diode. The results reported in this paper may provide a route to ZnO-based phosphor-converted LEDs for future lighting or displaying purpose. 相似文献
18.
The absorption spectrum of acetylene-d has been observed at high resolution between 6470 and 6630 cm−1 using an external cavity diode laser. Three cold bands have been observed: the strong 2ν1 band, the weaker ν1 + ν2 + 2ν5 band, and the (ν1 + ν3 + ν5)1 band, which gains its intensity through Coriolis resonance with 2ν1. Centers of unblended lines are determined with an accuracy of approximately 10 MHz. 相似文献
19.
Semiconductor laser with optical feedback emitting chaotic optical signal can be treated as chaotic carrier transmitter. Based on laser rate equations, we numerically study the effect of external injection light on the bandwidth of chaotic carrier transmitter. Our numerical simulation shows that the bandwidth of the chaotic carrier transmitter can be enhanced significantly by external photons injection. Compared with the 2 GHz relaxation oscillation frequency of a solitary laser diode without optical injection, the bandwidth of a chaotic carrier transmitter is expanded to 14.5 GHz with injection parameter at kinj = 0.39. Simulation results also demonstrate that the enhanced bandwidth depends obviously on the frequency detuning between the external injection laser diode and the chaotic carrier transmitter. The maximum bandwidth of the chaotic transmitter can be obtained when the frequency of the injected light is higher than the central frequency of the carrier transmitter between 2 GHz and 4 GHz. 相似文献
20.
B. Mardiana Sahbudin Shaari P. Susthitha Menon H. Hazura A.R. Hanim N. Arsad H. Abdullah 《Optik》2014
This paper highlights the study on various structure of silicon-on-insulator (SOI) optical phase modulators based on free carrier dispersion effect. The proposed modulators employ the forward biased P-I-N diode structure integrated in the waveguide and will be working at 1.55 μm optical telecommunications wavelength. Three kinds of structure are compared systematically where the p+ and n+ doping positions are varied. The modeling and characterization of the SOI phase modulators was carried out by 3D numerical simulation package. Our results show that the position of doping regions have a great influences to the device performance. It was discovered that the best structure in this work demonstrated modulation efficiency of 0.015 V cm with a length of 155 μm. 相似文献