• Title/Summary/Keyword: evanescent-mode

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Investigation of Importance of Evanescent Modes in Predicting the Transformation of Water Waves by the Linear Wave Theory: 2. Numerical Experiments (선형파 이론에 의한 파랑변형 예측시 소멸파 성분의 중요성 검토 2. 수치 실험)

  • 이창훈;조대희;조용식
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.15 no.1
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    • pp.51-58
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    • 2003
  • The magnitude of evanescent modes in terms of dynamics it investigated in case that the transformation of water waves is predicted by the linear wave theory. For the waves propagating over two steps, the eigenfunction expansion method is used to predict the amplitudes of reflected and transmitted waves by the component of evanescent modes as well as propagating modes. Then. the relative importance of evanescent modes to the propagating modes is investigated. The numerical experiments find that the evanescent modes are pronounced at the relative water depth of k$_1$h$_1$=0.11$\pi$ and the water depth ratio of h$_2$/h$_1$ close to zero.

Measurements of Evanescent Wave using a Mano-size Optical Probe (나노 사이즈 광프로브에 의한 에버네슨트파의 측정)

  • 최영규
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.1
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    • pp.30-35
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    • 2004
  • We have carried out a basic experiment in order to develope a super high-resolution optical microscope which transcend the limitation of diffraction and the wavelength of lightwave. The image of this scope is composed by measuring the evanescent wave which is localized on the surface of the testing materials. A detecting probe was fabricated with a single mode optical fiber to be sharpened by the chemical etching, and drived by PZT. The standing wave of $0.33\mu\textrm{m}$ wavelength evanescent wave which was generated from the $0.78\mu\textrm{m}$-wavelength semiconductor laser was detected by the $0.5\mu\textrm{m}$-thickness optical fiber probe.

Analysis and Design of Si3N4 Rib-optical Waveguides for Evanescent-wave Integrated-optical Biosensors (소산파 집적광학 바이오센서에 적합한 Si3N4 립-광도파로 해석 및 설계에 관한 연구)

  • Jung, Hongsik
    • Korean Journal of Optics and Photonics
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    • v.30 no.1
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    • pp.15-22
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    • 2019
  • $Si_3N_4$ rib-optical waveguides for evanescent-wave integrated-optical biosensors were analytically interpreted, to derive the single-mode propagation conditions. The integrated-optical biosensor structure based on two-mode interference was proposed, and the rib width and thickness and core thickness for a single-mode and two-mode waveguide (sensing region) were proposed to be $3{\mu}m$, 2 nm, and 150 nm and $3{\mu}m$, 20 nm, and 340 nm respectively. The optical characteristics of each guided-wave mode were investigated utilizing the film mode-matching (FMM) analysis.

Effects of evanescent modes on three-dimensional depression of seabed (3차원 함몰 지형에서 소멸파 성분의 영향)

  • Jung, Tae-Hwa;Kim, Hyung-Joon;Cho, Yong-Sik
    • Journal of Korea Water Resources Association
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    • v.42 no.12
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    • pp.1125-1133
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    • 2009
  • Evanescent modes which are the other solutions of the Laplace equation for the linear dispersion equation may affect the wave transformation especially when a water depth varies abruptly. In this study, the effects of evanescent modes for a three-dimensional depression of seabed are investigated by using the eigenfunction expansion method. A convergence test is first carried out by changing numbers of domains and evanescent modes. The wave transformation for various depressions of seabed is then calculated under condition that the solution of the eigenfunction expansion method is converged.

Improvement Air Gap Control for SIL based Near-Field Recording System (SIL을 이용한 근접장 기록계에서의 서보 방식의 개발)

  • Kim, Joong-Gon;Kim, Tae-Hun;Jeong, Jun;Park, No-Cheol;Yang, Hyun-Seok;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.3 no.1
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    • pp.1-4
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    • 2007
  • A high density optical data storage device has been required for many years. In the field of the optical data storage, a near-field recording (NFR) technology is considered as a next generation one for achieving the high data density. Due to an evanescent wave effect occurred under 100nm distance which is the excessively small distance between the SIL and the disc, the most significant and difficult problem in this technology is to maintain a gap between a solid immersion lens (SIL) and a disc. Also, maintaining the gap under at least 50nm is required in the NFR gap servo system to use the evanescent wave effect efficiently. There are some institutes that have shown the novel gap servo control. In general, they use a mode switching servo method which consists of approach, hand-over and gap control mode. However there is a critical problem such as an overshoot at the tuning point from the approach mode to the hand-over mode, which may cause a collision between the SIL and the disc. In this paper, we show our NFR system and an improved gap servo system using an exponential function as the approach mode which can reduce the overshoot.

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Effects of Light Incident Mode on Optical Scattering of Au Nanoparticle by Localized Surface Plasmon Resonance (빔의 입사모드가 금 나노입자의 국소표면플라즈몬 산란광에 미치는 영향)

  • Lee, Taek-Sung;Lee, Kyeong-Seok;Kim, Won-Mok;Lee, Jang-Kyo;Byun, Seok-Joo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.4
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    • pp.307-313
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    • 2009
  • Quantitative analysis of optical scattering intensities from a Au nanoparticle with a diameter of 100 nm, which is effected by the localized surface plasmon resonance (LSPR), were numerically carried out by using a dark-field detection scheme on prism basal plane for two different beam incident modes of reflectance (R-mode) and transmittance (T-mode). Two-dimensional finite difference time domain (FDTD) algorithm was adopted, and its applicabilibility was verified by comparing the simulation results with the theoretical ones. Simulation results of the scattered light intensities from a Au nanoparticle revealed that the scattered intensity of the T-mode was much stronger than that of R-mode. Comparison of the calculated results with the theoretical intensity distribution on the prism showed that the scattered intensity is marimized when the evanescent field, which is generated from the interface of prism and air at TIR angle, is coupled with Au nanoparticle.

Study On the End Vibration of a Cylindrical Shell (원통셸의 끝단 진동에 대한 연구)

  • Lee, J.Y.;Kil, H.G.;Lee, C.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1321-1324
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    • 2007
  • In this paper, the in-plane end vibration of a cylindrical shell has been analyzed. The theoretical result has showed that the strong in-plane vibration at the ends of the cylindrical shell can be generated by the evanescent wave field, which is excited along about half the length of the shell. This has been also observed from experimental result. The evanescent waves are generated due to mode conversion of elastic waves at the ends of the cylindrical shells. The results show that the strong in-plane end vibration can be generated in cylindrical shells.

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A Study on the Normalized Analysis of Sensitivity Optimization of Evanescent-Field, Integrated-Optic Biosensor based on Planar Optical Waveguide (평면 광도파로 기반의 소산파 집적광학 바이오센서의 감지도 최적화에 관한 정규화 해석에 관한 연구)

  • Jung, Hongsik
    • Journal of Sensor Science and Technology
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    • v.27 no.1
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    • pp.25-30
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    • 2018
  • Closed-form analytical expressions and 3-dimensional normalized charts for the homogeneous sensing and surface sensing structures are derived to provide the conditions for the maximum sensitivity of integrated-optic biosensors based on evanescent-wave and stepindex planar optical waveguides. The analysis is made for transverse electric (TE) polarization mode, in both cases where the measurand is homogeneously distributed in the cover (namely, homogeneous sensing), and where it is an ultrathin film on the waveguide-cover interface (namely, surface sensing).

Design of Waveguide Low Pass Filter using Rectangular Rings and Ridges (직사각형 링과 리지 구조를 이용한 도파관 저역통과 여파기 설계)

  • Oh, Taek-Kyun;Choi, Hak-Keun;Lee, Hyoung-Ki
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.1
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    • pp.7-13
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    • 2014
  • In this paper, a novel waveguide low pass filter for satellite communication is proposed. The proposed low pass filter is designed to obtain wideband characteristics without the interference of higher order modes, sufficient attenuation in the stop-band and small sized lightweight characteristics by evanescent-mode ridge structure. To improve return loss and rejection loss, rectangular ring is inserting around the ridges in the waveguide. Input and output ports of the low pass filter is designed by using the impedance step structure for the impedance matching of the filter. The proposed waveguide low pass filter is fabricated and then measured as return loss over 19.5 dB, insertion loss less than 1.41 dB at the pass-band of 7.25 ~ 8.4 GHz and rejection loss over 67.2 dB at the stop-band of 12.25 ~ 14.5 GHz.

$LP_{11}$ Mode Fiber Optic Resonant Ring Interferometer with a $LP_{11}$ Modal Filter ($LP_{11}$ 결모양 빛살거르게를 사용한 $LP_{11}$ 결모양 빛살 광섬유 공진고리 간섭계)

  • 이현재;이두희;서상준;양진성
    • Korean Journal of Optics and Photonics
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    • v.2 no.1
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    • pp.20-25
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    • 1991
  • Using evanescent field coupling between single ($LP_{01}$) and double ($LP_{01}, LP_{11}$) mode optical fiber, we selected LPII mode beam. With a $LP_{11}$ mode beam from a double mode fiber. we fabricated $LP_{11}$ mode fiber optic resonant ring interferometer, and assured that the guided mode is $LP_{11}$ mode from a radiation beam coming through the prism output coupler. When an external perturbation applied to the signal arm of the $LP_{11}$ fiber optic resonant ring interferometer, we examined the change of radiation mode coming from a prism output coupler and an end of optical fiber. Using two photodiode, LPn mode beam converted to voltage. This two output voltages is applied to X and Y terminal of oscilloscope to display circular motion on oscilloscope.

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