- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Udine, Italy (2019.9.4-2019.9.6)] 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Hybrid Method For Electromagnetic Modelling of Coherent Radiation in Semiconductor Lasers
摘要： In this paper hybrid method for electromagnetic (EM) modelling of coherent radiation in semiconductor lasers is presented. Described approach consist of drift diffusion (DD) model and electromagnetic simulation. Four-level two-electron atomic system with Pauli Exclusion Principle (PEP) extended by electric pumping ratio has been used as lasing model.
关键词： ADE,drift diffusion,PEP,device,FDTD,simulation,nonlinear optics
更新于2025-09-12 10:27:22
-
Near-Field Enhancement and Polarization Selection of a Nano-System for He-Ne Laser Application
摘要： In this paper, we focus on transmission behavior based on the single aperture with a scatter. Both the near-field enhancement and polarization selection can be achieved numerically with a proposed nano-system under He-Ne laser wavelength. The nano-system consists of an Ag antenna, a wafer layer, an Ag film with an aperture and a dielectric substrate. Numerical results show that the near-field enhancement is related to the FP-like resonance base on surface plasmon polaritons (SPPs) in the metal–isolator–metal (MIM) waveguide for transverse magnetic (TM) polarization. The near-field optical spot is confined at the aperture export with a maximal electric intensity 20 times the value of the incident field for an antenna length of 430 nm. The transmission cutoff phenomenon for transverse electric (TE) polarization is because the transmission is forbidden for smaller aperture width. High extinction ratios of 9.6 × 10?8 (or 70.2 dB) and 4.4 × 10?8 (or 73.6 dB) with antenna lengths of 130 nm and 430 nm are achieved numerically with the nano-system. The polarization selective property has a good angular tolerance for oblique angles smaller than 15?. The spectral response is also investigated. We further demonstrate that the nano-system is applicable for another incident wavelength of 500 nm. Our investigation may be beneficial for the detection of polar molecules or local nano polarized nanosource.
关键词： transmission,FDTD method,nano-system,extinction ratio
更新于2025-09-12 10:27:22
-
A 2?×?1 all-optical multiplexer using Kerr nonlinear nano-plasmonic switch
摘要： In this paper, a novel surface plasmon polariton based 2 × 1 multiplexer, which is based on an adder module and an all-optical controllable nano-plasmonic switching module is presented. It is shown that by applying a pump light, the transmissions of the input signals into the output waveguide can be controlled. The operation of the proposed device is investigated through the use of coupled-mode theory and finite-difference time-domain method. In the proposed adder module, the transmissions of the input signals at the working wavelengths are about 0.7. Based on the simulation results, by applying a pump light intensity of 150 KW/cm2 the transmissions of input signals alter with the extinction ratio of 22.04 dB, which shows a significant switching effect. For a pump light intensity of 150 KW/cm2 the switching times of input signals are measured about 560 fs. It is expected that the proposed 2 × 1 multiplexer can be used in all-optical signal processing, nano-plasmonic circuits, communication, etc.
关键词： Coupled-mode theory (CMT),Kerr nonlinearity,Racetrack-shaped ring resonator,Finite-difference time-domain (FDTD),Nano-plasmonic switch,All-optical multiplexer
更新于2025-09-12 10:27:22
-
Impact of silver nanogratings for enhanced light absorption in plasmonic based photodetector
摘要： Recent era has witnessed a wide interest of researchers for the development of nano scale high speed photodetectors. Now days, optical communication systems demand these detectors with light enhancement along with high gain and bandwidth. Plasmonics based photodetectors with gold nanogratings are employed in literature for high responsivity and miniaturization. However, these devices need to be explored for other metals as gold being very costly. In this work, plasmonic based photodetector is designed with silver nanogratings and analyzed over varying shapes like rectangular, trapezoidal, ellipse and parabolic taper. Enhanced light absorption with quenching factor of 73.96% is achieved with rectangular grooves in near infrared region as compared to other shapes.
关键词： Surface plasmons (SPs),Absorption,Nano gratings,Enhancement,Plasmonic,Photo-detectors,Subwavelength aperture,Finite-difference,Time-domain (FDTD) simulation
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - A Simple Approach, Based on Coupled Mode Theory, to Study PhC Lasers
摘要： PhC lasers have attracted large interest as efficient light-sources in on-chip and chip-to-chip interconnections. They allow for scaling the active volume while maintaining the high cavity Q-factor, thus exhibiting low threshold current and operating energy [1,2]. Methods for studying these laser cavities are typically based on FDTD simulations, which are often time-consuming and do not allow to catch the most relevant physics of these devices. We propose here an alternative and simple approach to analyze active PhC waveguides and lasers. Our approach is based on coupled-mode theory, which has proved to be an effective tool to study lasers with periodic gain and/or refractive index perturbation, as standard DFB lasers. We apply this method to PhC line-defect waveguides and lasers with a small complex refractive index perturbation (to account for gain and refractive index variation) with respect to a reference, unpumped PhC line-defect waveguide [3]. The optical electric field of the TE-like guided mode is expanded as sum of the forward- and backward-propagating Bloch modes of the passive waveguide; the equation governing the evolution (cid:549)+,-(z) of the Bloch modes along the perturbed waveguide are: (cid:2034)(cid:1878)(cid:2032)+ = (cid:1861)(cid:2018)11,(cid:1869)=0((cid:2033)) (cid:2032)++ (cid:1861)(cid:2018)12,(cid:1869)=1((cid:2033)) (cid:1857)+2(cid:1861)(cid:2012)((cid:2033))(cid:1878)(cid:2032)(cid:3398) (cid:3398)(cid:2034)(cid:1878)(cid:2032)(cid:3398) = (cid:1861)(cid:2018)21,(cid:1869)=(cid:3398)1((cid:2033))(cid:1857)(cid:3398)2(cid:1861)(cid:2012)((cid:2033))(cid:1878)(cid:2032)++ (cid:1861)(cid:2018)11,(cid:1869)=0((cid:2033)) (cid:2032)(cid:3398) (1) where k11,q=0 and k12,q=1;21q=-1 are the self- and cross- coupling coefficients calculated as in [3]. An example is in Fig. 1 for refractive index perturbation ((cid:507)(cid:81)s(cid:143)(cid:19)) and positive gain g0. This figure proves that, differently from standard DFB lasers, the cross-coupling coefficient is always comparable to the self-coupling coefficient. This is because of the strong z-component of the TE-like electric field of the fundamental guided mode. The coupling coefficients are gain-dependent since gain, not present in the holes, is also a periodic perturbation; k11,q=0 and k12,q=1;21q=-1 are also frequency-dependent because of the slow-light effect and they significantly increase as frequency approaches the band edge. Therefore, Bloch modes at shorter frequency and/or with higher gain of the active waveguide will go through a stronger distributed feedback effect with respect to longer frequency Bloch modes and/or lower active waveguide gain. Based on this model, we have simulated a laser cavity with the geometry as in Fig. 2a, consisting of a pumped active section, a rear passive mirror with material refractive index smaller than the active section and a front passive buffer with material refractive index equal (Type A) , slightly larger (Type B) or smaller (Type C) than the active region. Based on the model of eq. (1), we have calculated the rear and buffer mirror reflection coefficients (S11) (Fig.2a). Threshold condition, found searching for frequency and gain g0 satisfying rL(cid:11)(cid:550)(cid:12)(cid:194) rR(cid:11)(cid:550)(cid:15)(cid:74)0)=1, is in Fig.2b as function of the front buffer number of cells. The different trends of the threshold gain with the number of buffer cells can be explained by the interplay, in determining rR(cid:11)(cid:550)(cid:15)(cid:74)0), between the distributed feedback in both the active region and the front buffer. In Type C, the latter is dominant (nearly doubled with respect to the active region feedback); therefore, threshold gain diminishes as the front buffer reflection increases (similar to a FP laser with increase of the front mirror reflection). On the contrary, in Type A and Type B the role of distributed feedback in the active region plays a major role and the threshold depends on the interference between the active region distributed feedback and the front buffer back reflection. For this reason, Type B shows an optimum number of cells minimizing threshold gain.
关键词： coupled-mode theory,FDTD simulations,PhC lasers,distributed feedback,Bloch modes
更新于2025-09-12 10:27:22
-
Nonlinear Rectangular Photonic Crystal Fiber (PCF) for Optical Communication Exclusively Super Continuum Generation
摘要： A rectangular PCF structure in BK7 glass with inner and outer cladding is used to investigate effective mode field area, high nonlinear coefficient, and confinement loss and dispersion property using 2D FDTD technique. The PCF structure is purposed to design with pitches and air hole diameter in a periodic array fashion. The different properties of PCF structure like mode field area, nonlinear coefficient, confinement loss and dispersion are to be analyzed. The variation is investigated with change of different parameters like ?1, d1/?1, ?2/?1, and d1/d2 for a wide range of wavelength. The proposed rectangular PCF structure has slightly more nonlinear coefficient (γ=36.98 W-1km-1) than the highly nonlinear silica photonic crystal fiber (γ=35 W-1 km-1) at a wavelength of 1.55 μm with almost same mode field area (Aeff ~ 2.8 μm2). This result seems to be important in super-continuum generation and nonlinear fiber optics.
关键词： Kerr nonlinearity,FDTD method,Super-continuum generation,PCF
更新于2025-09-12 10:27:22
-
[IEEE 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Sarajevo, Bosnia and Herzegovina (2019.9.2-2019.9.4)] 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Realization of sucrose sensor using photonic waveguide: An application to biophotonics
摘要： A photonic waveguide sensor is explored in the present paper for effective sensing of sucrose concentration in an aqueous solution at a wavelength of 1550 nm by employing a 1-D photonic waveguide structure. The proposed structure comprises three layers, out of which odd layers are considered to be an InAs compound semiconductor having thickness of 700nm each whereas an even layer is air having thickness of 300 nm. Additionally, the effect of concentration variation of sucrose is theoretically examined with reference to reflected intensity, diffraction loss and transmitted intensity at the aforementioned waveguide. Reflected intensity from the said structure is computed through band gap analysis by a manipulating finite difference time domain (FDTD) technique, whereas diffraction loss and transmitted intensity are computed through numerical formulations. Further, simulation for diffraction loss with respect to different sucrose concentration has been carried out and interestingly the upshots revealed logarithmic deviation of diffraction efficiency with reference to variation in sucrose concentration from 10 gm/100ml to 70 gm/100ml. Apart from this, it is also revealed that there exists noteworthy shifts in both reflected as well as transmitted intensity with rise in sucrose concentration. Additionally, it is affirmed that both reflected light intensity and transmitted light intensity can be nicely fitted linear relationship having R2=0.998 and with a precise R2=0.9919 respectively, which claim an accurate sensing of sucrose concentration by using the proposed semiconductor based photonic waveguide and find applications in biophotonics.
关键词： band gap,sucrose sensing,photonic waveguide,FDTD
更新于2025-09-12 10:27:22
-
Indium‐rich InGaN/GaN solar cells with improved performance due to plasmonic and dielectric nanogratings
摘要： In this study, we propose an indium‐rich InGaN/GaN p‐i‐n thin‐film solar cell which incorporates a dual nanograting (NG) structure: Ag nanogratings (Ag‐NGs) on the backside of the solar cell and gallium nitride nanogratings (GaN‐NGs) on the frontside. Finite‐difference time‐domain (FDTD) simulation results show that the dual NG structure couples the incident sunlight to the plasmonic and photonic modes, thereby increasing the absorption of the solar cell in a broad spectral range. It is observed that the solar cells having the dual nanograting structures have a significant enhancement in light absorption as compared to cells having either no nanogratings or having only the frontside nanogratings or only the backside nanogratings. Analysis of light absorption in solar cells containing the dual NG structures showed that the absorption enhancement of longer wavelengths is mostly due to the Ag‐NGs on the backside and of shorter wavelengths is mostly due to the GaN‐NGs on frontside of the solar cell. The Jsc and power conversion efficiency (PCE) are calculated under AM1.5G solar illumination and are observed to be significantly enhanced due to the presence of optimized dual NG structures. While there is an increase in Jsc from 17.88 to 23.19 mA/cm2 (~30% enhancement), there is an increase in PCE from 15.49% to 20.24% (~31% enhancement) under unpolarized light (average of TM and TE). Moreover, the study of oblique light incidence shows significantly larger Jsc of the dual nanograting solar cells compared to the cells with no nanogratings.
关键词： broadband absorption,FDTD simulations,light trapping,surface plasmons,nanogratings,InGaN solar cells
更新于2025-09-11 14:15:04
-
MODE SPLITTING BASED ON THE COUPLING BETWEEN MODES OF TWO NANODISKS CAVITIES AND A PLASMONIC WAVEGUIDE
摘要： A metal-insulator-metal (MIM) plasmonic waveguide coupled with two nanodisks as a resonator has been examined and numerically simulated with the ?nite-di?erence time-domain (FDTD) and analytically by the Temporal Coupling Mode Theory (CMT). Based on the three-level system, the strong destructive interference between the two resonators leads to the distinct mode splitting response. The characteristics of mode splitting show that there is anomalous dispersion with the novel fast-light feature at the resonance. Meanwhile, the slow light characteristic can also be achieved in the system at wavelengths of the split modes. The relationship between the transmission characteristics and the geometric parameters is examined. The results show that the modulation depth of the mode splitting transmission spectrum of 80% with 0.175 ps fast-light e?ect of resonance can be achieved, while for the two modes these values are around 30% with ?0.18 ps slow light-e?ect. There is a good agreement between the FDTD simulated transmission features and CMT. The characteristics of the system indicate critical potential applications in integrated optical circuits such as slow-light and fast-light devices, optical monitoring, an optical ?lter, and optical storage.
关键词： slow-light,plasmonic waveguide,FDTD,mode splitting,CMT,fast-light,nanodisks
更新于2025-09-11 14:15:04
-
[IEEE 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting - Atlanta, GA, USA (2019.7.7-2019.7.12)] 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting - Generalized Tensor FDTD Method for Sloped Plasmonic Interfaces
摘要： A tensor finite-difference time-domain (FDTD) method for sloped interfaces is generalized to dispersive media and applied to the study of plasmonic periodic structures formed by silver nanorods. Conventional staircased FDTD exhibits poor convergence properties in this situation, as plasmonic fields are strongly localized right where staircasing errors occur, namely at the air-silver interface. Alternative methods that have been proposed for this problem include the use of a triangular mesh or effective permittivity models that lead to a fourth-order auxiliary differential equation (ADE) connecting D and E at the interface. The proposed approach offers high accuracy, still employing a rectangular FDTD mesh, thus striking a very appealing balance between accuracy and computational efficiency.
关键词： numerical techniques,plasmonic interfaces,tensor FDTD,silver nanorods,dispersive media
更新于2025-09-11 14:15:04