Showing papers on "Optical microcavity published in 2014"
TL;DR: This work uses strong coupling in an optical microcavity to mix the electronic transitions of two J-aggregated molecular dyes and uses both non-resonant photoluminescence emission and photolumsinescence excitation spectroscopy to show that hybrid-polariton states act as an efficient and ultrafast energy-transfer pathway between the two exciton states.
Abstract: Strongly coupled optical microcavities containing different exciton states permit the creation of hybrid-polariton modes that can be described in terms of a linear admixture of cavity-photon and the constituent excitons. Such hybrid states have been predicted to have optical properties that are different from their constituent parts, making them a test bed for the exploration of light-matter coupling. Here, we use strong coupling in an optical microcavity to mix the electronic transitions of two J-aggregated molecular dyes and use both non-resonant photoluminescence emission and photoluminescence excitation spectroscopy to show that hybrid-polariton states act as an efficient and ultrafast energy-transfer pathway between the two exciton states. We argue that this type of structure may act as a model system to study energy-transfer processes in biological light-harvesting complexes.
352 citations
TL;DR: This work reports for the first time, to their knowledge, single nanoparticle detection by monitoring the beat frequency of split-mode Raman lasers in high-Q optical microcavities in both air and an aqueous environment, with an ultralow detection limit.
Abstract: Ultrasensitive nanoparticle detection holds great potential for early-stage diagnosis of human diseases and for environmental monitoring. In this work, we report for the first time, to our knowledge, single nanoparticle detection by monitoring the beat frequency of split-mode Raman lasers in high-Q optical microcavities. We first demonstrate this method by controllably transferring single 50-nm–radius nanoparticles to and from the cavity surface using a fiber taper. We then realize real-time detection of single nanoparticles in an aqueous environment, with a record low detection limit of 20 nm in radius, without using additional techniques for laser noise suppression. Because Raman scattering occurs in most materials under practically any pump wavelength, this Raman laser-based sensing method not only removes the need for doping the microcavity with a gain medium but also loosens the requirement of specific wavelength bands for the pump lasers, thus representing a significant step toward practical microlaser sensors.
234 citations
TL;DR: It is believed that the strong coupling regime presents an opportunity to modify the energy transfer pathways within photosynthetic organisms without modification of the molecular structure.
Abstract: Strong exciton-photon coupling is the result of a reversible exchange of energy between an excited state and a confined optical field. This results in the formation of polariton states that have energies different from the exciton and photon. We demonstrate strong exciton-photon coupling between light-harvesting complexes and a confined optical mode within a metallic optical microcavity. The energetic anti-crossing between the exciton and photon dispersions characteristic of strong coupling is observed in reflectivity and transmission with a Rabi splitting energy on the order of 150 meV, which corresponds to about 1,000 chlorosomes coherently coupled to the cavity mode. We believe that the strong coupling regime presents an opportunity to modify the energy transfer pathways within photosynthetic organisms without modification of the molecular structure.
127 citations
TL;DR: In this paper, the authors reported the realization of a spatially and spectrally tunable air-gap Fabry-Perot type microcavity of high finesse and cubic-wavelength-scale mode volume.
Abstract: We report the realization of a spatially and spectrally tunable air-gap Fabry-Perot type microcavity of high finesse and cubic-wavelength-scale mode volume. These properties are attractive in the fields of opto-mechanics, quantum sensing, and foremost cavity quantum electrodynamics. The major design feature is a miniaturized concave mirror with atomically smooth surface and radius of curvature as low as 10 μm produced by CO2 laser ablation of fused silica. We demonstrate excellent mode-matching of a focussed laser beam to the microcavity mode and confirm from the frequencies of the resonator modes that the effective optical radius matches the physical radius. With these small radii, we demonstrate wavelength-size beam waists. We also show that the microcavity is sufficiently rigid for practical applications: in a cryostat at 4 K, the root-mean-square microcavity length fluctuations are below 5 pm.
79 citations
TL;DR: In this paper, the spatial profile of the optical pump was used to select the dominant lasing mode in nearly circular semiconductor microdisks by shaping the spatial profiles of optical pump.
Abstract: We demonstrate lasing mode selection in nearly circular semiconductor microdisks by shaping the spatial profile of optical pump. Despite of strong mode overlap, adaptive pumping suppresses all lasing modes except the targeted one. Due to slight deformation of the cavity shape and boundary roughness, each lasing mode has distinct emission pattern. By selecting different mode to be the dominant lasing mode, we can switch both the lasing frequency and the output direction. Such tunability by external pump after the laser is fabricated enhances the functionality of semiconductor microcavity lasers.
66 citations
TL;DR: A PC-TIR sensor has been used for the label-free measurements of cardiac biomarkers by monitoring the changes in the resonant condition of the cavity due to biomolecular binding processes, and detection limit of cTnI with a concentration as low as 0.1ngmL(-1) has been achieved.
64 citations
TL;DR: It is shown that the interplay of the laser lights and the cavity gives rise to rich quantum phases and generates a large synthetic magnetic field for the dressed spin state, which may facilitate the study of the quantum Hall effect in ultracold atomic gases.
Abstract: We propose a novel scheme to generate the spin-orbit coupling for a condensate placed inside an optical cavity by using a standing wave and a traveling wave. It is shown that the interplay of the laser lights and the cavity gives rise to rich quantum phases. Our scheme also generates a large synthetic magnetic field for the dressed spin state, which may facilitate the study of the quantum Hall effect in ultracold atomic gases.
62 citations
TL;DR: In this paper, an all-optical switching operation using the Kerr effect in a silica toroid microcavity was demonstrated, with an input power of 2 mW. This value is the smallest among all previously reported on-chip optical Kerr switches.
Abstract: We demonstrate experimentally an all-optical switching operation using the Kerr effect in a silica toroid microcavity. Thanks to the small mode volume and high quality factor of the silica toroid microcavity, we achieved on-chip optical Kerr switching with an input power of 2 mW. This value is the smallest among all previously reported on-chip optical Kerr switches. We also show that this value can be reduced to a few tens of μW by employing a mode with a Q factor of > 2 × 10⁷.
53 citations
TL;DR: A hybrid optical microcavity from rolled-up polymer/oxide/polymer nanomembranes presents its excellent capability for environmental relative humidity detection and demonstrates that the thin walls of the tubular microccavities contribute to a high detection sensitivity compared to other microc Cavities.
Abstract: A hybrid optical microcavity from rolled-up polymer/oxide/polymer nanomembranes presents its excellent capability for environmental relative humidity detection. When exposed to a moist surrounding, poly(acrylic acid)/poly(ethylenimine) polymers swell greatly due to the absorption of water molecules, which thus leads to an increased wall thickness of the tubular optical microcavity and therefore presents a profound wavelength redshift of its whispering-gallery mode resonance. These experiments fit well with the calculation based on the Mie-scattering theory. Theoretical calculation also demonstrates that the thin walls of our tubular microcavities contribute to a high detection sensitivity compared to other microcavities. Our work could lead to new designs and applications of optical microcavities.
47 citations
TL;DR: This work presents the first scaled microcavity system which enables the creation of large numbers of highly uniform, tunable light-matter interfaces using ions, neutral atoms or solid-state qubits.
Abstract: Optical cavities are of central importance in numerous areas of physics, including precision measurement, cavity optomechanics and cavity quantum electrodynamics. The miniaturisation and scaling to large numbers of sites is of interest for many of these applications, in particular for quantum computation and simulation. Here we present the first scaled microcavity system which enables the creation of large numbers of highly uniform, tunable light-matter interfaces using ions, neutral atoms or solid-state qubits. The microcavities are created by means of silicon micro-fabrication, are coupled directly to optical fibres and can be independently tuned to the chosen frequency, paving the way for arbitrarily large networks of optical microcavities.
41 citations
TL;DR: A semiclassical model is developed to obtain the absorption spectra of a weak probe field under the influence of strong exciton-photon coupling with the cavity field and it is demonstrated that a cavity field with an average photon number near unity can significantly modify the absorptive and dispersive response of the medium to a strong probe field at a different frequency.
Abstract: We predict that an ensemble of organic dye molecules with permanent electric dipole moments embedded in a microcavity can lead to strong optical nonlinearities at the single-photon level. The strong long-range electrostatic interaction between chromophores due to their permanent dipoles introduces the desired nonlinearity of the light-matter coupling in the microcavity. We develop a semiclassical model to obtain the absorption spectra of a weak probe field under the influence of strong exciton-photon coupling with the cavity field. Using realistic parameters, we demonstrate that a cavity field with an average photon number near unity can significantly modify the absorptive and dispersive response of the medium to a weak probe field at a different frequency. Finally, we show that the system is in the regime of cavity-induced transparency with a broad transparency window for dye dimers. We illustrate our findings using pseudoisocyanine chloride (PIC) J-aggregates in currently available optical microcavities.
TL;DR: In this article, the authors briefly recall the basic concepts of quantum optics and properties of semiconductor quantum dot (QD) which are necessary to the understanding of the physics of single-photon generation with single QDs.
Abstract: In this contribution, we briefly recall the basic concepts of quantum optics and properties of semiconductor quantum dot (QD) which are necessary to the understanding of the physics of single-photon generation with single QDs. Firstly, we address the theory of quantum emitter-cavity system, the fluorescence and optical properties of semiconductor QDs, and the photon statistics as well as optical properties of the QDs. We then review the localization of single semiconductor QDs in quantum confined optical microcavity systems to achieve their overall optical properties and performances in terms of strong coupling regime, efficiency, directionality, and polarization control. Furthermore, we will discuss the recent progress on the fabrication of single photon sources, and various approaches for embedding single QDs into microcavities or photonic crystal nanocavities and show how to extend the wavelength range. We focus in particular on new generations of electrically driven QD single photon source leading to high repetition rates, strong coupling regime, and high collection efficiencies at elevated temperature operation. Besides, new developments of room temperature single photon emission in the strong coupling regime are reviewed. The generation of indistinguishable photons and remaining challenges for practical single-photon sources are also discussed.
TL;DR: Three resonant excitations—photons, phonons and electrons—can interact strongly with each other providing modulation of the V CSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein, and modulation ofThe lasing intensity at frequencies up to 40 GHz is observed.
Abstract: Vertical-cavity surface-emitting lasers consist of an active medium in between two distributed Bragg reflectors. Czerniuk et al. show that the resonant mechanical modes of these periodic structures efficiently modulate the laser emission intensity with frequencies of up to 40 GHz.
TL;DR: In this article, the authors present a review of the work performed in the area of coherent access technologies employing vertical cavity surface emitting lasers (VCSELs), including optical transmission over a passive fiber link with coherent detection.
Abstract: We present a review of research performed in the area of coherent access technologies employing vertical cavity surface emitting lasers (VCSELs). Experimental demonstrations of optical transmission over a passive fiber link with coherent detection using VCSEL local oscillators and directly modulated VCSEL transmitters at bit rates up to 10 Gbps in the C-band as well as in the O-band are presented. The broad linewidth and frequency chirp associated with directly modulated VCSELs are utilized in an envelope detection receiver scheme which is demonstrated digitally (off-line) as well as analog (real-time). Additionally, it is shown that in the optical front-end of a coherent receiver for access networks, the 90 ° hybrid can be replaced by a 3-dB coupler. The achieved results show that VCSELs are attractive light source candidates for transmitter as well as local oscillator for coherent detection PONs.
TL;DR: Recent advancements in biomimetic chemistry from other sensor approaches to these devices to continue the development of new analytical tools rely on a firm understanding of how proper surface chemistries can be merged with whispering gallery mode optical microcavities to achieve not just a platform, but a precisely defined tool for a given application.
Abstract: Whispering gallery mode optical microcavities have significantly impacted the field of label-free optical biodetection. By combining the evanescent field generated by the microcavity with biomimetic surface chemistries, it is now possible to use the microcavities as not only biosensors, but as analytical tools to explore fundamental chemical and physical interactions of biomolecules and biomaterials. Here, we review the recent advancements of these applications from a surface chemistry perspective. For example, surface chemistries can be generated from a standard coating perspective, where active molecules, such as laser or fluorescent dyes can be embedded in a biomaterial matrix. Alternatively, direct and reverse grafting techniques can be used to tether biomolecules of interest to the surface to tune the surface properties (hydrophobicity/hydrophilicity, protein adsorption, cell adhesion, etc.). Finally, we discuss how to apply advancements in biomimetic chemistry from other sensor approaches to these devices to continue the development of new analytical tools. All of these developments rely on a firm understanding of how proper surface chemistries can be merged with whispering gallery mode optical microcavities to achieve not just a platform, but a precisely defined tool for a given application.
TL;DR: The condensation of microcavity exciton polaritons under optical excitation in a microCavity with four embedded InGaAs quantum wells is reported on, characterized by a distinct non-linearity in the input-output-characteristics and a characteristic persisting emission blueshift with increased particle density.
Abstract: We report on the condensation of microcavity exciton polaritons under optical excitation in a microcavity with four embedded InGaAs quantum wells. The polariton laser is characterized by a distinct non-linearity in the input-output-characteristics, which is accompanied by a drop of the emission linewidth indicating temporal coherence and a characteristic persisting emission blueshift with increased particle density. The temporal coherence of the device at threshold is underlined by a characteristic drop of the second order coherence function to a value close to 1. Furthermore an external electric field is used to switch between polariton regime, polariton condensate and photon lasing.
TL;DR: Two hybrid entanglement concentration protocols based on quantum dots (QDs) and optical microcavity coupled systems are presented, which can be further used for parity check that allows a quantum nondemolition measurement on the spin parity.
Abstract: We present two hybrid entanglement concentration protocols based on quantum dots (QDs) and optical microcavity coupled systems. The system is theoretically analyzed and used for photon and electron hybrid entanglement generation. Also, the proposed system can be further used for parity check that allows a quantum nondemolition measurement on the spin parity. By performing parity check process on electron spins, the entangled state can be concentrated into maximally entangled state efficiently.
TL;DR: Characterization of single TAT crystals reveals highly variable emission spectra and excited state dynamics - properties which strongly influence photovoltaic performance, and concludes that this variability is a result of long-lived low-energy trap-emission from packing defects.
Abstract: Recent synthetic work has realized a novel (n-type) small-molecule acceptor, 7,8,15,16-tetra-aza-terrylene (TAT), single-crystals of which can be grown oriented along the c-axis crystallographic direction, and over-coated with pentacene to form a highly ordered donor/acceptor interface for use in organic photovoltaic devices. However, characterization of single TAT crystals reveals highly variable emission spectra and excited state dynamics – properties which strongly influence photovoltaic performance. Through the use of single-crystal widefield imaging, photoluminescence spectroscopy, time correlated single photon counting, and resonant Raman studies, we conclude that this variability is a result of long-lived low-energy trap-emission from packing defects. Interestingly, we also discovered that TAT crystals whose width exceeds ∼200 nm begin acting as waveguides and optical microcavity resonators for their own photoluminescence. Several strategies are proposed for leveraging the size-dependant optical properties of TAT pillars to further enhance device performance using this active layer design.
TL;DR: In this paper, a thermal infrared (IR) detector based on an ultra-high-quality-factor (Q) whisperinggallery-mode (WGM) microtoroidal silica resonator was demonstrated.
Abstract: We demonstrate a thermal infrared (IR) detector based on an ultra-high-quality-factor (Q) whispering-gallery-mode (WGM) microtoroidal silica resonator and investigate its performance to detect IR radiation at 10 μm wavelength. The bandwidth and the sensitivity of the detector are dependent on the power of a probe laser and the detuning between the probe laser and the resonance frequency of the resonator. The microtoroid IR sensor achieved a noise-equivalent-power (NEP) of 7.46 nW, corresponding to an IR intensity of 0.095 mW/cm2.
TL;DR: In this article, a vapor-grown thiophene/phenylene co-oligomer (TPCO) single crystal with in-plane polarization component was used as the gain medium in an optical microcavity.
Abstract: We have achieved to observe vertical cavity surface emitting lasing (VCSEL) from an optically pumped organic single crystal. A vapor-grown thiophene/phenylene co-oligomer (TPCO) single crystal with in-plane polarization component was used as the gain medium in an optical microcavity. Since the top and bottom surfaces of the TPCO crystal serve as high-quality resonators, well-defined Fabry-Perot resonance is achieved. Furthermore, by using high reflectivity distributed Bragg reflector as the cavity resonator, we have observed lasing emissions with a line width of 0.9 nm and a threshold of ∼3 mJ/cm2. The VCSEL-type optical feedback configuration demonstrated in this study is expected to be one of the available means to realize the electrically pumped organic laser device.
TL;DR: Using a theoretical model, the Q-factor and modal volume of the cavity formed by a dipole-cylindrical-waveguide system is evaluated and it is shown that such a cavity allows access to both the strong and weak coupling regimes of cavity quantum electrodynamics.
Abstract: An ideal optical cavity operates by confining light in all three dimensions. We show that a cylindrical waveguide can provide the longitudinal confinement required to form a two dimensional cavity, described here as a self-formed cavity, by locating a dipole, directed along the waveguide, on the interface of the waveguide. The cavity resonance modes lead to peaks in the radiation of the dipole-waveguide system that have no contribution due to the skew rays that exist in longitudinally invariant waveguides and reduce their Q-factor. Using a theoretical model, we evaluate the Q-factor and modal volume of the cavity formed by a dipole-cylindrical-waveguide system and show that such a cavity allows access to both the strong and weak coupling regimes of cavity quantum electrodynamics.
TL;DR: In this article, a thermal infrared (IR) detector based on an ultra-high-quality-factor (Q) whisperinggallery-mode (WGM) microtoroidal silica resonator is presented.
Abstract: We demonstrate a thermal infrared (IR) detector based on an ultra-high-quality-factor (Q) whispering-gallery-mode (WGM) microtoroidal silica resonator, and investigate its performance to detect IR radiation at 10 micron wavelength. The bandwidth and the sensitivity of the detector are dependent on the power of a probe laser and the detuning between the probe laser and the resonance frequency of the resonator. The microtoroid IR sensor achieved a noise-equivalent-power (NEP) of 7.46 nW, corresponding to IR intensity of 0.095 mW/cm^2
TL;DR: In this article, phase diffusion in a Bose-Einstein condensate of light in a dye-filled optical microcavity was studied, i.e., the spreading of the probability distribution for the condensates phase.
Abstract: We study phase diffusion in a Bose--Einstein condensate of light in a dye-filled optical microcavity, i.e., the spreading of the probability distribution for the condensate phase. To observe this phenomenon, we propose an interference experiment between the condensed photons and an external laser. We determine the average interference patterns, considering quantum and thermal fluctuations as well as dissipative effects due to the dye. Moreover, we show that a representative outcome of individual measurements can be obtained from a stochastic equation for the global phase of the condensate.
Patent•
22 Apr 2014TL;DR: In this article, the authors proposed an optical comb generator with an optical path and a high-Q resonator coupled in the optical path inside the laser cavity to produce optical comb of different optical frequencies.
Abstract: The disclosed technology, in one aspect, includes an optical comb generator device which includes a laser cavity that includes an optical gain material to provide an optical gain and an optical path to allow laser light to circulate inside the laser cavity; and a high-Q resonator optically coupled in the optical path inside the laser cavity so that the laser light generated and sustained inside the laser cavity is in optical resonance with the high-Q resonator to cause laser light stored inside the high-Q resonator to have an optical intensity above a four wave mixing threshold of the high-Q resonator to cause parametric four wave mixing so as to produce an optical comb of different optical frequencies.
TL;DR: The result on the control of the mediated photon-photon interaction, very similar to the 'gate' control in an optical transistor, may be experimentally observable and applied to ultra-fast intrachip/interchip optical interconnects, improvement in the performance of fiber-optic communication networks, and developments of optical digital computers and quantum communications.
Abstract: The possibility for controlling both the probe-field optical gain and absorption, as well as photon conversion by a surface-plasmon-polariton near field is explored for a quantum dot located above a metal surface. In contrast to the linear response in the weak-coupling regime, the calculated spectra show an induced optical gain and a triply-split spontaneous emission peak resulting from the interference between the surface-plasmon field and the probe or self-emitted light field in such a strongly-coupled nonlinear system. Our result on the control of the mediated photon-photon interaction, very similar to the 'gate' control in an optical transistor, may be experimentally observable and applied to ultra-fast intrachip/interchip optical interconnects, improvement in the performance of fiber-optic communication networks, and developments of optical digital computers and quantum communications.
TL;DR: Laser-microcavity relative frequency fluctuations caused by thermal locking are studied and it is found that the locking of laser-microCavity detuning causes microcavities temperature fluctuations that transfer pump frequency noise onto the microc Cavity modes within the thermal locking bandwidth.
Abstract: As thermo-optic locking is widely used to establish a stable frequency detuning between an external laser and a high Q microcavity, it is important to understand how this method affects microcavity temperature and frequency fluctuations. A theoretical analysis of the laser-microcavity frequency fluctuations is presented and used to find the spectral dependence of the suppression of laser-microcavity, relative frequency noise caused by thermo-optic locking. The response function is that of a high-pass filter with a bandwidth and low-frequency suppression that increase with input power. The results are verified using an external-cavity diode laser and a silica disk resonator. The locking of relative frequency fluctuations causes temperature fluctuations within the microcavity that transfer pump frequency noise onto the microcavity modes over the thermal locking bandwidth. This transfer is verified experimentally. These results are important to investigations of noise properties in many nonlinear microcavity experiments in which low-frequency, optical-pump frequency noise must be considered.
TL;DR: It is demonstrated that by applying the drag force one can direct more than 90% of the polariton flow toward the desired branch of the switch with no hysteresis.
Abstract: We propose a design of a Y-shaped electrically controlled optical switch based on the studies of propagation of an exciton–polariton condensate in a patterned optical microcavity with an embedded quantum well. The polaritons are driven by a time-independent force due to the microcavity wedge shape and by a time-dependent drag force owing to the interaction of excitons in a quantum well and the electric current running in a neighboring quantum well. It is demonstrated that by applying the drag force one can direct more than 90% of the polariton flow toward the desired branch of the switch with no hysteresis. By considering the transient dynamics of the polariton condensate, we estimate the response speed of the switch as 9.1 GHz. We also propose a design of the polariton switch in a flat microcavity based on the geometrically identical Y-shaped quantum wells where the polariton flow is only induced by the drag force. The latter setup enables one to design a multiway switch that can act as an electrically c...
TL;DR: It is shown that such a structure can sustain SPP eigenmodes whose fields are tightly trapped within the microcavity, making it attractive for broad applications in filters, light sources, energy storage, and on-chip optical communications.
Abstract: We theoretically demonstrate a subwavelength spoof surface-plasmon–polariton (SPP) microcavity on a planar metallic surface working at the terahertz regime with a high-quality factor and ultra-small mode volume. The microcavity is based on plasmonic and metamaterial notions, and it consists of an easy-to-manufacture circular aperture and a bell-shaped metallic core. It is shown that such a structure can sustain SPP eigenmodes whose fields are tightly trapped within the microcavity. Using the proposed structure, a total Q factor of 1000 (including losses from metals at low temperatures) and subwavelength mode volume of 0.00018(λ/2)3 can be achieved in the THz range for the fundamental surface-plasmonic eigenmode at room temperature. Moreover, the key figures of merit such as resonance frequency can be flexibly tuned by modifying the geometry of the microcavity, making it attractive for broad applications in filters, light sources, energy storage, and on-chip optical communications.
TL;DR: In this paper, the authors show that due to a dimensionality mismatch between the two-dimensional cavity photons and the three-dimensional arrangement of molecules, the system permits superfluid regimes where the relevant molecular degrees of freedom are collective Dicke states rather than individual excitations.
Abstract: Motivated by recent experiments reporting Bose-Einstein condensation of light coupled to incoherent dye molecules in a microcavity, we show that due to a dimensionality mismatch between the two-dimensional cavity photons and the three-dimensional arrangement of molecules, the system permits superfluid regimes where the relevant molecular degrees of freedom are collective Dicke states rather than individual excitations. For sufficiently high dye concentration, Dicke states become robust against local decoherence. In the limit when all dye molecules become excited, this system also shows Mott-Hubbard physics, despite the absence of an underlying lattice.
TL;DR: In this article, an arc-shaped optical cavity structure of a superconducting nanowire single photon detector (SNSPD) was analyzed by performing optical simulations using finite-difference time-domain method.
Abstract: Optical cavity structure has been proven to be a crucial factor for obtaining high detection efficiency in superconducting nanowire single photon detector (SNSPD). Practically, complicated fabrication processes may result in a non-ideal optical cavity structure. The cross-sectional transmission electron microscope (TEM) image of SNSPD fabricated in this study shows unexpected arc-shaped optical cavities which could have originated due to the over-etching of SiO2 layer while defining NbN nanowire. The effects of the arc-shaped optical cavity structure, such as the wavelength dependence of the optical absorption efficiency for different polarization, were analyzed by performing optical simulations using finite-difference time-domain method. The central wavelength of the device is found to exhibit a blue shift owing to the arced cavity structure. This effect is equivalent to the flat cavity with a reduced height. The results may give interesting reference for SNSPD design and fabrication.