Prism-waveguide Coupling Research Articles

Tunable modulation of photonic spin Hall effect by using a prism-coupling waveguide with hyperbolic metamaterials

The properties of the photonic spin Hall effect (PSHE) excited in a prism-coupling waveguide with hyperbolic metamaterial (HMM) are investigated theoretically. The proposed waveguide is composed of four layers including a prism, HMM, thin metal, and air. Both type I and type II HMMs can be created through multilayer realization comprising alternating subwavelength layers of plasma and dielectric or by embedding plasma in a host dielectric matrix, and they are both considered in this study. Our results reveal that the horizontal PSHE shifts in the type I HMM waveguide are significantly suppressed, whereas the horizontal PSHE shifts in the type II HMM waveguide can be enhanced by more than 20 times. The results show that the behavior of vertical PSHE shifts in both types of HMM waveguides are similar and significantly suppressed. The results also show that the HMM and metal layer thicknesses extremely alter the PSHE shifts, especially for the horizontal PSHE shifts in the type II HMM waveguide. Furthermore, the PSHE shifts with different operating wavelengths are calculated and discussed. In addition, the optimal parameters for achieving huge PSHE shifts are explored and presented.

Spin Hall effect of light in a prism-waveguide coupling structure with a magneto-optical bimetallic film

We study the spin hall effect of light (SHEL) in prism coupling configuration with magneto-optical (MO) material and bimetallic film which is called MOSHEL. Compared with single gold film, the surface plasmon resonance (SPR) with the bimetallic film can achieve minimum reflectivity and the difference between transverse shifts with opposite magnetic field directions can achieve 13 μm at resonance angle. By adjusting the thickness of magneto-optical layer and bimetallic film, we find that both SPR and SHEL can be modulated by the magnetic field. Base on this we propose that MOSHEL can be enhanced by MOSPR for the first time.

Performance analysis of a liquid-filled glass prism-coupled metal-clad planar waveguide sensor

The performance of a metal-clad planar waveguide-based sensor coupled with a liquid-filled prism is studied and is compared with a similar waveguide sensor coupled with a solid prism. The characteristic equations of these waveguides are obtained by matching field components at various boundaries, and the reflectivity of these waveguides is obtained using transfer matrix method. The obtained dispersion characteristic shows that the transverse electric field components are loosely bound in liquid-filled prism-coupled waveguide-based sensor. Unlike to solid prism-coupled waveguide sensor, the performance of liquid-filled prism-coupled waveguide sensor increases with increase of effective refractive index. Hence, the proposed liquid-filled prism-coupled waveguide-based sensor shows better performance at high effective refractive index.

Refractive index detection via magneto-optical Goos-Hänchen effect in multilayer structure containing magnetic film

Refractive index detection based on magneto optical Goos-Hänchen (MOGH) effect is proposed in a prism-waveguide coupling structure. Double metal layers are adopted to enhance the MOGH effect. MO transfer matrix method is utilized to calculate the reflectivity of the waveguide. The influences of metal material and thickness are analyzed based on simulation results. Calculation results show the second metal layer determines the MOGH shift distribution in angular spectrum. Based on field distributions in the prism-waveguide coupling structure with symmetric and asymmetric metal layers, we choose asymmetric metal layers in the refractive index sensing model to realize higher sensitivity. A maximum sensitivity of 16.7 mm/RIU can be achieved based on the MOGH effect in the prism-waveguide coupling structure.

Low-loss prism-waveguide optical coupling for ultrahigh-Q low-index monolithic resonators

While compact and low-loss optical coupling to ultrahigh-quality-factor (Q) crystalline resonators is important for a wide range of applications, the major challenge for achieving this coupling stems from the relatively low refractive index of the crystalline resonator host material compared to those of the standard waveguide coupling materials. We report the first demonstration of a single-mode waveguide structure (prism-waveguide coupler) integrated on a low-loss compact silicon nitride platform resulting in low-loss and efficient coupling to magnesium fluoride crystalline resonators by achieving the phase-matched and the mode-matched evanescent wave coupling. The coupling is characterized with 1 dB loss at 1550 nm wavelength. We further present a photonic integrated chip containing a pair of waveguides successfully coupling light into and out of the resonator, demonstrating a planar-waveguide-coupled crystalline resonator with a loaded Q of 1.9×109. We assemble this waveguide-coupled resonator and a distributed-feedback-laser chip into a butterfly package to realize a miniature Kerr optical frequency comb source using self-injection locking of the distributed feedback laser to the waveguide-coupled crystalline resonator.

Periodic Imbert-Fedrov shift in a prism-coupling waveguide with epsilon-near-zero metamaterial

We study the periodic Imbert-Fedrov (IF) shift in a prism-coupling waveguide with epsilon-near-zero (ENZ) metamaterial. We take into account the influence of ENZ metamaterial and gold layer thicknesses as well as the metal material on the IF effect in our proposed waveguide. The calculation method is derived and theoretical analysis is given. Based on simulation results, we can find periodic IF shifts can be observed which provides us an opportunity to realize enhanced IF effect at various incident angle. Further calculations shows that ENZ metamaterial thickness determines the maximum IF shift value, the periodic property and incident angle corresponding to IF shift peak. However, the metal thickness and permittivity only has an important influence on maximum IF shift value which will not affect the periodic property and incident angle corresponding to IF shift peak.

Goos–Hänchen effect in semiconductor metamaterial waveguide and its application as a biosensor

We investigate Goos–Hanchen (GH) effect in a prism waveguide coupling structure with semiconductor metamaterial (SMM) of ZnGaO/ZnO multilayer and explore the possibility as a biosensor. The GH effect in three different waveguides and their performances as a refractive index sensor to detect glycerol concentration in water are analyzed. The SMM brings a periodic property of GH shift peaks which is not found in other waveguides. It is also verified that setting coupling layer of the prism waveguide coupling structure as sensing area is an effective method to significantly increase the sensitivity to refractive index variation. A schematic diagram for the biosensor configuration is designed, and the sensitivity distribution for different glycerol water index is given. Calculation results show that in the proposed biosensor the maximum sensitivity reaches 3.2 × 106 μm/RIU and resolution reaches 1.6 × 10−7 (around 1.33306) with high sensitive position sensitive detector.

Thermo-optic Imbert-Fedorov effect in a prism-waveguide coupling system with silicon-on-insulator

In this paper, a prism-waveguide coupling system based on silicon-on-insulator (SOI) is revisited. We find that thermo-optic Imbert-Fedorov (TOIF) effect displays in this four-layer optical system which has not been proposed before. Furthermore, we discuss the TOIF shifts in prism/SiO2/Si/SiO2 and prism/Au/Si/SiO2 waveguides with different parameters and study the observed phenomena from physical point of view. It is shown that the maximum IF shift can achieve 140μm in a prism/Au/Si/SiO2 waveguide which is large enough to be directly measured by the calculation results. Accordingly, TOIF shift provides a temperature control method for the enhancement and modulation of IF shift.

Thermo-optic Goos–Hänchen effect in silicon-on-insulator waveguide

We study the thermo-optic Goos–Hanchen (TOGH) effect in a prism–waveguide coupling structure with silicon-on-insulator waveguide. Stationary-phase method is utilized to calculate the TOGH shift. When the waveguide is regarded as a two-dimensional planar waveguide, a nonlinear relation between GH shift and temperature is obtained. Based on the noticeable TOGH effect, a sensitive temperature modulator or sensor can be realized. As the waveguide width is limited, the proposed structure can be regarded as a three-dimensional rectangular waveguide. We explore the GH shift and TOGH effect for different modes propagating in rectangular waveguide which show different linear relations between GH shift and temperature, which can be used to design mode-selective device based on TO effect.

Large positive and negative lateral shift in prism-waveguide system with left-handed material of weak absorption

We study the mechanism of large positive and negative lateral shift in a prism-waveguide coupling system where the guiding layer is composed of left-handed material with weak absorption. As the giant lateral shift is always dramatically decreased by the loss of guiding layer, we introduce lossy cladding layer and substrate to realize large lateral shift in the above system, theoretical expression of lateral shift is derived and simulation results illustrate the appearance of large lateral shift.

Study of beam divergence of a fiber-bundle prism-coupled waveguide using ray tracing

Experimental and theoretical results of a two-stage beam shaping system based on a flexible plastic fiber-bundle and a prism duct are described in this study. An imaging technique is used to investigate the divergence effect on the output beam images and intensity profiles. Photograph pictures of the output beam at different axial distances are taken by a digital camera and the image data is converted into a response curve and presented in this study. According to the experimental results, the propagation in the free space transforms a square beam with a hat-top intensity distribution into a rectangular beam with a conical intensity distribution. For theoretical investigations, using VOB software a simulation is performed to analyze the reported beam shaping design. Ray tracing diagrams are presented to study the direct beam propagation, refracted rays and total reflection rays. The prism duct output beam dimension is determined as a function of distance from the prism exit face and the optimum condition for the maximum power transmission and best image quality is reported. The calculated output beam dimensions by VOB are compared with the experimental ones and there is a good agreement between the observed results.

Magneto-optical Goos-Hänchen effect in a prism-waveguide coupling structure.

We report a theoretical study of the enhanced Goos-Hänchen (GH) effect in a prism-waveguide coupling system with a magneto-optic thin film of Ce doped Y(3)Fe(5)O(12) (CeYIG). By magnetizing the CeYIG thin film along different directions, a variation of the GH shift can be observed, which is named as the MOGH (magneto-optical Goos-Hänchen) effect. The applied magnetic field direction is found to cause MOGH effect for light with different polarizations. As example systems, enhanced GH shift and MOGH effect is observed in both prism/Air/CeYIG/SiO(2) and prism/Au/CeYIG/SiO(2) structures, by applying opposite magnetic field across the CeYIG layer in a transverse magneto-optical Kerr effect (TMOKE) configuration. The GH and MOGH effect as a function of layer thicknesses, material refractive indices and magneto-optical properties are systematically simulated and discussed. It is observed that the coupling layer and MO layer thickness plays an important role of controlling the MOGH effect in the prism/Au/CeYIG/SiO(2) plasmonic waveguide structure. The MOGH effect shows high sensitivity to applied magnetic field and index variations, making it promising for applications such as optical switches, modulators, and chemical or biomedical index sensors.

Enhancement of Goos–Hänchen effect in a prism-waveguide system with biaxially anisotropic metamaterial

We study the mechanism of large lateral shift effect in a prism-waveguide coupling system where the guiding layer is composed of biaxially anisotropic metamaterial (BAM). We make use of stationary-phase approach to calculate the GH shift with different thickness of coupling layer and guiding layer, permittivity of coupling layer and imaginary parts of permittivity of BAM. Simulation results show that by the change of the above parameters, GH shift can be modulated sensitively. The physical explanation is given about these phenomenons and the proposed prism-waveguide system with BAM can be designed to realize different functions, such as thickness measurement, refractive index testing and absorption detection.

Net lateral shift of reflected beam in prism-waveguide coupling system due to guided wave resonance

When guided wave resonance occurs on the prism-waveguide coupling system (PWCS), the reflected beam undergoes angular shift which contributes to lateral shift of the reflected beam, in addition to the Goos–Hänchen (GH) lateral shift. We investigate the net lateral shift of the reflected beam at the Rayleigh range where the beam waist does not broaden obviously. It is shown that the incident angle associated with the maximum net lateral shift deviates from the resonant angle and the maximum net lateral shift is larger than GH shift. And at the same time, the net lateral shift is more sensitive than GH shift to the changes of PWCS parameters. Numerical simulation shows that the theory agrees well with numerical results when the beam width is large enough.

Refractive index detection based on a prism–waveguide coupling system with double-negative material

We construct a refractive index detection structure based on a prism–waveguide coupling system with double negative (DNG) material guiding layer, where surface plasmon resonance (SPR) is generated and the refractive index of lossless as well as lossy sample can be detected by the location of the incident light at which lateral shift peak appears. Simulation results show that when sample is lossy, more than one lateral shift peaks appear at different incident angle when other parameters are fixed once the intrinsic and radiative dampings satisfy the sufficient condition of equation for a large lateral shift.

Giant lateral shift in a prism-waveguide coupling system with anisotropic metamaterial and its application in precision processing

We study the lateral shifts of reflected light beams in a prism-waveguide system with uniaxially anisotropic metamaterial, and four sufficient conditions for the appearance of large lateral shift are determined. Based on the high sensitivity of the proposed system, we explore the application of the proposed prism-waveguide system in precision processing, including a sample counter used in production line and a planeness detector used in detecting the roughness of dielectric surface.

Origin of large lateral shift in a prism⿿waveguide coupling system with metamaterial

We study the lateral shifts of reflected light beams in a prism⿿waveguide system with lossless or lossy metamaterial, four sufficient conditions for the appearance of large lateral shift is concluded when the metamaterial is lossless, and the influence of lossy metamaterial on the properties of lateral shift is also analyzed by simulation results.

Experimental Investigation of First Hyperpolarizability by a Prism Coupling Waveguide Method

The complex first hyperpolarizability of chromophore for electrooptic effect has been determined by a prism coupling waveguide method. By measuring the field-induced changes in the reflected intensity of the prism–waveguide coupling system at different guided wave resonance dips, the real and imaginary parts of the first hyperpolarizability of the chromophore are simultaneously obtained without using the Kramers–Kronig transformation.

Physical origin of large positive and negative lateral optical beam shifts in prism–waveguide coupling system

Large lateral beam shift in prism–waveguide coupling system is theoretically analyzed from the viewpoint of interference between multiple reflected beam constituents. It is shown that the reflected beam is a result of interference between two beams: the beam directly reflected from the prism and the total leaky beam coming from guided mode. The thickness of coupling layer determines the amplitude of the total leaky beam, and further determines the sign (positive or negative) of the reflected beam shift. Because of interference between two beams, intrinsic damping itself plays an important role in deciding the distortion of the reflected beam.

Beam shape and intensity profile of a fiber-bundle prism-coupled waveguide

Design and performance of a two-stage optical beam shaping system based on a plastic fiber-bundle prism-coupled waveguide is described in this study. Such systems offer practical means to modify and change the output beam shape at two stages and also provide quantitative information concerning the output beam intensity profile. It is possible to obtain reflection and image transmittance data by using a light source for the illumination and image analysis by a CCD/digital camera. Using the active lighting, the reflection data and image profiles for the output beam are obtained by a CCD camera and presented in this study. The photograph picture of the illuminating LED beam just at its output point shows a circular shape with a radius of about 5 mm. Picture of the fiber-bundle output beam is also taken, which shows a linear arrangement of circular spot lights almost similar in cross section. The output beam cross section at this stage is in rectangular shape with a dimension of 30 mm width and 3 mm height. In another study CCD images at prism exit face is obtained and image profile is investigated. The final output beam cross section at the second stage of beam shaping is a square with a dimension of about 5 by 5 mm. The transmitted output beam power is also measured at different stages. The conversion efficiency for the fiber bundle at first stage beam shaping is about 70% and for the overall system is about 15%. In another study the relative reflected light off the prism entering face is measured by using two fiber probes in the stripe cable, which shows the ability to monitor such reflections for selecting the prism duct with a lower reflection loss.