Total Internal Reflection Structure Research Articles

Method of measuring one-dimensional photonic crystal period-structure-film thickness based on Bloch surface wave enhanced Goos–Hänchen shift

This paper puts forward a novel method of measuring the thin period-structure-film thickness based on the Bloch surface wave (BSW) enhanced Goos–Hänchen (GH) shift in one-dimensional photonic crystal (1DPC). The BSW phenomenon appearing in 1DPC enhances the GH shift generated in the attenuated total internal reflection structure. The GH shift is closely related to the thickness of the film which is composed of layer-structure of 1DPC. The GH shifts under multiple different incident light conditions will be obtained by varying the wavelength and angle of the measured light, and the thickness distribution of the entire structure of 1DPC is calculated by the particle swarm optimization (PSO) algorithm. The relationship between the structure of a 1DPC film composed of TiO2 and SiO2 layers and the GH shift, is investigated. Under the specific photonic crystal structure and incident conditions, a giant GH shift, 5.1 × 103 times the wavelength of incidence, can be obtained theoretically. Simulation and calculation results show that the thickness of termination layer and periodic structure bilayer of 1DPC film with 0.1-nm resolution can be obtained by measuring the GH shifts. The exact structure of a 1DPC film is innovatively measured by the BSW-enhanced GH shift.

基于全内反射结构的多自由曲面准直透镜设计

基于全内反射结构的多自由曲面准直透镜设计

A Bio-molecular Sensor Based on Optical Weak Measurement

We developed a phase-sensitive sensor based on the optical weak measurement for label-free detection of biomolecular interaction. The weak value amplification system can be implemented in common-path with total internal reflection structure. The phase difference between p and s polarizations caused by biomolecular recognition is measured by the central wavelength shift of the frequency domain weak measurement system. Structure of p and s polarizations in common-path makes system robust and stable. The applicability is illustrated by real-time monitoring interaction of biomolecules.

Resonant optical tunneling-induced enhancement of the photonic spin Hall effect

Due to the quantum analogy with optics, the resonant optical tunneling effect (ROTE) has been proposed to investigate both the fundamental physics and the practical applications of optical switches and liquid refractive index sensors. In this paper, the ROTE is used to enhance the spin Hall effect (SHE) of transmitted light. It is demonstrated that sandwiching a layer of a high-refractive-index medium (boron nitride crystal) between two low-refractive-index layers (silica) can effectively enhance the photonic SHE due to the increased refractive index gradient and an enhanced evanescent field near the interface between silica and boron nitride. A maximum transverse shift of the horizontal polarization state in the ROTE structure of about 22.25 µm has been obtained, which is at least three orders of magnitude greater than the transverse shift in the frustrated total internal reflection structure. Moreover, the SHE can be manipulated by controlling the component materials and the thickness of the ROTE structure. These findings open the possibility for future applications of photonic SHE in precision metrology and spin-based photonics.

Design Method for a Total Internal Reflection LED Lens with Double Freeform Surfaces for Narrow and Uniform Illumination

In this paper, we propose a novel differential equation method for designing a total internal reflection (TIR) LED lens with double freeform surfaces. A complete set of simultaneous differential equations for the method is derived from the condition for minimizing the Fresnel loss, illumination models, Snell's Law of ray propagation, and a new constraint on the incident angle of a ray on the light-exiting surface of the lens. The last constraint is essential to complete the set of simultaneous differential equations. By adopting the TIR structure and applying the condition for minimizing the Fresnel loss, it is expected that the proposed TIR LED lens can have a high luminous flux efficiency, even though its beam-spread angle is narrow. To validate the proposed method, three TIR LED lenses with beam-spread angles of less than 22.6° have been designed, and their performances evaluated by ray tracing. Their luminous flux efficiencies could be obviously increased by at least 35% and 5%, compared to conventional LED lenses with a single freeform surface and with double freeform surfaces, respectively.

Tunneling mode in a frustrated total internal reflection structure with hyperbolic metamaterial

We study the tunneling modes in a frustrated total internal reflection (FTIR) structure with hyperbolic metamaterial (HMM). The physical mechanism of tunneling mode is analyzed by the condition of general zero average permittivity. The influence of anisotropy, loss and dispersion of HMM on tunneling modes is discussed based on simulation results. Tunneling mode merging or splitting can be realized by adjusting the thickness of air or HMM. We can also find the absorption of HMM significantly reduces the transmittance peak of tunneling mode. When a recently reported HMM of ZnAlO/ZnO multilayer is introduced in the FTIR structure, the combined action of HMM loss and dispersion brings many small tunneling modes in the angular spectrum. The tunneling mode in the proposed structure can be used to design filters and wavelength selectors which may also have applications in wavelength de-multiplexing in optical communications.

Lateral shifts and photon tunneling in a frustrated total internal reflection structure with a negative-zero-positive index metamaterial

Motivated by the realization of the Dirac point (DP) with a double-cone structure for optical field in the negative-zero-positive index metamaterial (NZPIM), the lateral shift and tunneling time of photon tunneling through a frustrated total internal reflection structure containing a NZPIM barrier are investigated by employing Artman's stationary phase method. Near the DP, the lateral shift can vary from positive to negative and the photon tunneling displays a superluminal dynamic. Because of the Hartman effect, both lateral shift and tunneling time tend to a saturation value when the barrier thickness increases. These results may lead to potential applications in integral optics and optical-based devices and also suggest analogous phenomena of valance electron in single-layered carbon graphene.

All-optical modulator with long range surface plasmon resonance

An all-optical modulator based on long range surface plasmon resonance with respect to Kerr effect induced refractive index changes is proposed and numerically investigated. The photosensitivity of the Kerr-polymer induces the variation of refractive index under illumination of pump light with different intensity. Long range surface plasmon resonance excited by an attenuated total internal reflection structure is utilized in the design for its high sensitivity to refractive index. For the structure with optimal parameters, the modulator is able to vary the reflectance from 0.04 to 0.74 by applying a pump light as low as 0.44GW/cm2.

Sensitive Real-Time Monitoring of Refractive Indexes Using a Novel Graphene-Based Optical Sensor

Based on the polarization-sensitive absorption of graphene under conditions of total internal reflection, a novel optical sensor combining graphene and a microfluidic structure was constructed to achieve the sensitive real-time monitoring of refractive indexes. The atomic thickness and strong broadband absorption of graphene cause it to exhibit very different reflectivity for transverse electric and transverse magnetic modes in the context of a total internal reflection structure, which is sensitive to the media in contact with the graphene. A graphene refractive index sensor can quickly and sensitively monitor changes in the local refractive index with a fast response time and broad dynamic range. These results indicate that graphene, used in a simple and efficient total internal reflection structure and combined with microfluidic techniques, is an ideal material for fabricating refractive index sensors and biosensor devices, which are in high demand.

Broad Flat-Top Adjustable Filter With Metamaterial

A flat-top filter with adjustable, broad, and robust tunneling band is proposed, where the barrier is composed of multiple layers including a medium with adjustable permeability (MAP) and metamaterial. Using a frustrated total internal reflection structure composed of glass-MAP-metamaterial-MAP-glass, the flat-top tunneling band can be realized and shifted to other frequency bands by adjusting the permeability of MAP to satisfy permeability and incident angle match conditions. In addition, our filter has a more robust flat-top tunneling band compared with other flat-top filters when the thickness of every layer changes. At last, the effect of metamaterial loss is considered.

All-optical modulator with long range surface plasmon resonance

An all-optical modulator based on long range surface plasmon resonance with respect to Kerr effect induced refractive index changes is proposed and numerically investigated. The photosensitivity of the Kerr-polymer induces the variation of refractive index under illumination of pump light with different intensity. Long range surface plasmon resonance excited by an attenuated total internal reflection structure is utilized in the design for its high sensitivity to refractive index. For the structure with optimal parameters, the modulator is able to vary the reflectance from 0.04 to 0.74 by applying a pump light as low as 0.44GW/cm2.

Unusual photon tunneling in the frustrated total internal reflection structure includingindefinite metamaterials

The transmittance and the behavior of an evanescent field in the frustrated total internalreflection structure composed of isotropic media and anisotropic indefinite metamaterial areobtained by the transfer matrix formulation. The evanescent waves can evolve into differentforms associated with the different dispersion relations of the indefinite metamaterial. Incutoff and anti-cutoff media, the evanescent waves are amplified and even total photontunneling is obtained under some conditions. Then the evanescent wave can be transformedinto a propagation wave and highly efficient tunneling is also achieved in a always-cutoffmedium.

The properties of photon tunnelling in a frustrated total internal reflection structure with an indefinite metamaterial slab

The tunnelling time and lateral shift of photon tunnelling through the frustrated total internal reflection structure containing indefinite metamaterials are obtained by employing the stationary-phase approximation. It is found that the photon tunnelling only occurs when the barrier is thin enough. For the indefinite metamaterial with one-sheet hyperbolic dispersion, the anomalous total reflection occurs, and the negative lateral shift and tunnelling time can be obtained. The negative tunnelling time indicates that superluminal propagation could be observed when a photon tunnels through the indefinite metamaterial. Both lateral shift and tunnelling time tend to a saturation value, respectively, as the barrier thickness increases. Moreover, the dependence of properties of four kinds of indefinite metamaterial on the thickness, the permittivity and permeability tensors is discussed.

Photon tunneling in a frustrated total internal reflection structure with a lossy indefinite metamaterial barrier

We study the phenomenon of photon tunneling through a frustrated total internal reflection structure with a dispersive lossy indefinite metamaterial barrier. The tunneling coefficient, lateral shift, and tunneling time for different incident light waves through the barrier are obtained by employing the stationary-phase approximation. The properties of tunneling time and lateral shift are discussed for different metamaterial parameters. It is shown that negative lateral shift and tunneling time can appear in the cutoff and always cutoff metamaterials. The lateral shift can be enhanced by adjusting the light frequency, the barrier thickness, and the permittivity or permeability of the indefinite metamaterial. In addition, it is found that the lateral shift can be resonantly amplified due to the weak loss of the indefinite metamaterial slab. The Hartman effects of the lateral shift and tunneling time are also demonstrated.