Total Reflection Condition Research Articles

Structured Light Control and Diagnostics Using Optical Crystals

We describe experimental results exposing the possibilities of optical crystals, especially anisotropic and birefringent, for creation, control, and diagnostics of structured light fields with singular and extraordinary properties. The efficiency of birefringent media is demonstrated for purposeful generation of optical beams with phase singularities (optical vortices) and desirable patterns of internal energy flows, in both the mono- and polychromatic light. On the other hand, anisotropic micro-objects can be used as probing bodies for investigation of the peculiar features of internal energy flows and corresponding momentum and angular momentum distributions in structured light fields. In particular, the specific mechanical action of light fields, formed under the total-reflection conditions, has been detected that confirms the existence of “extraordinary” dynamical characteristics of evanescent light waves predicted theoretically: the “transverse” momentum and “vertical” spin and their dependence on the incident beam polarization. The results can be useful for the optical trapping and micromanipulation techniques, including the biomedical and pharmaceutical applications.

Total reflection hard x-ray photoelectron spectroscopy: Applications to strongly correlated electron systems

We demonstrate that total reflection hard x-ray photoelectron spectroscopy (TR-HAXPES) is a versatile method for elucidating a difference between surface and bulk electronic states of strongly correlated electron systems, complementing conventional bulk sensitive hard x-ray photoelectron spectroscopy (HAXPES). To demonstrate the experimental feasibility of the method, we investigated ${\mathrm{La}}_{0.6}{\mathrm{Sr}}_{0.4}{\mathrm{MnO}}_{3}$ and the electron-doped high-${T}_{\mathrm{C}}$ superconductor ${\mathrm{La}}_{1.9}{\mathrm{Ce}}_{0.1}{\mathrm{CuO}}_{4}$. From the incident angle dependence of the spectral line shapes, we found that the surface-sensitive TR-HAXPES measurement equivalent to soft x-ray photoelectron spectroscopy is possible in the total reflection condition. The results strongly suggest that this method allows us to measure both surface and bulk electronic states without making any changes to experimental setup such as the energy resolution, x-ray energy, and the beamline.

Basic principles of information security monitoring in physical channels of optical access networks

The article presents theoretical information about the methods of information retrieval from optical fibers. The simplest analyzed method is the bending of the optical fiber when violating the conditions of total internal reflection. The functional dependence of the losses and the level of radiated power on the parameters and bending geometry of the optical fiber are given. In this case, the introduced losses are monitored in the monitoring system for detecting fiber bends. The structure, principles of operation, and trends in the development of monitoring systems are presented. The main technical characteristics of optical radiation detection devices are demonstrated.

Sensing of Surface and Bulk Refractive Index Using Magnetophotonic Crystal with Hybrid Magneto-Optical Response.

We propose an all-dielectric magneto-photonic crystal with a hybrid magneto-optical response that allows for the simultaneous measurements of the surface and bulk refractive index of the analyzed substance. The approach is based on two different spectral features of the magneto-optical response corresponding to the resonances in p- and s-polarizations of the incident light. Angular spectra of p-polarized light have a step-like behavior near the total internal reflection angle which position is sensitive to the bulk refractive index. S-polarized light excites the TE-polarized optical Tamm surface mode localized in a submicron region near the photonic crystal surface and is sensitive to the refractive index of the near-surface analyte. We propose to measure a hybrid magneto-optical intensity modulation of p-polarized light obtained by switching the magnetic field between the transverse and polar configurations. The transversal component of the external magnetic field is responsible for the magneto-optical resonance near total internal reflection conditions, and the polar component reveals the resonance of the Tamm surface mode. Therefore, both surface- and bulk-associated features are present in the magneto-optical spectra of the p-polarized light.

Optical bistability in reflection from multilayer metal-dielectric structure with Kerr nonlinearity

Both static and dynamic characteristics of light reflected from a specially designed multilayer metal-dielectric structure with Kerr nonlinearity have been studied in this work. Various regimes of nonlinear reflection from the structure have been demonstrated, including bistable switching between low and high reflection states, which occurs at low intensity of the incident light due to a significant enhancement in the optical field in the nonlinear layer under conditions of total internal reflection. This nonlinear structure has been proposed to use as an optically controlled intracavity laser modulator.

Wavelength and chemical potential dependence of optical beam shifts in graphene

We predict the spatial and angular Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts in partial (PR) and total internal reflection (TIR) conditions for fundamental Gaussian mode beams of a wide range of wavelength (400–1300 nm) impinging upon a graphene-coated dielectric surface. The GH and IF shifts turn out to be extremely dependent upon the chemical potential of graphene along with the wavelength of the incident light, thus enabling one to appropriately choose the operating wavelength and tune the chemical potential in the desired region to obtain maximum beam shifts in graphene. We also show that the typical features of the optical beam shifts are potentially linked with the optical conductivity of single-layer graphene. We expect the current study to be of fundamental significance in the field of optoelectronics and device industry based on graphene and other 2D materials.

X-ray diffraction by surface acoustic waves

The possibilities are presented of X-ray diffraction methods for studying the propagation of surface acoustic waves (SAWs) in solids, including diffraction under total external reflection conditions and Bragg diffraction, using acoustically modulated X-ray multilayer mirrors and crystals. SAW propagation was studied using both meridional and sagittal diffraction geometries where the SAW wavevectors and X-ray photons are collinear or perpendicular, respectively. SAW propagation in a crystal leads to sinusoidal modulation of the crystal lattice and the appearance of diffraction satellites on the rocking curve. The intensities and angular positions of these diffraction satellites are determined by the SAW wavelength, amplitude and attenuation. Therefore, diffraction methods allow the analysis of the SAW propagation process and determination of SAW parameters. The influence of X-ray energy on diffraction by acoustically modulated crystals is studied for the first time. It is shown that changes in the X-ray energy can change the angular region where diffraction satellites exist under conditions of total external reflection. By contrast, in the Bragg diffraction region changes in the X-ray photon energy lead to changes in the X-ray penetration depth into the crystal and redistribution of the diffracted intensity among diffraction satellites, but do not change the angular divergence between diffraction satellites on the rocking curve. It is also shown that, in X-ray diffraction on acoustically modulated crystals on a number of successive reflections, a decrease in interplanar spacing leads to an increase in the number of diffraction satellites and a redistribution of diffracted radiation between them.

Study on the mechanisms of curved water jet fiber-guided laser technology

The emergence of a novel technology, curved water jet fiber (CWJF)-guided laser, will broaden the application of water jet-guided laser in surface high precision and no damage micromachining, such as micro-texture treatment, drilling and grooving, etc., of inclined and curved workpiece, in particular, like some large and heavy parts that are difficult to move and rotate. In addition, the novel scheme of high precision, low damage, and circular section processing with the transmission laser and cooling effect of CWJF will be investigated. In this study, the parametric control of water jet deflection is explored using the model of the deflection trajectory of water jet discretized into continuously released water droplets under a nonuniform electric field, in which results show that large deflection angle and displacement can be obtained with high voltage, small distance, and low velocity. Optical transmission system models of CWJF-guided laser under related parametric groups are established through 3D physical reconstruction models of CWJF by using the deflection trajectory. The theoretical calculation of meeting total reflection conditions of incident rays and visualization analyses of CWJF formed-guided laser indicate laser beam can be transmitted effectively. The laser beam is still confined to CWJF and transmitted forward. The methods and results presented in this study will provide the theoretical support and reference for the control of CWJF formation and research of characteristics about CWJF-guided laser during this novel technology development journey.

Quantum weak measurement of Goos–Hänchen shift in monolayer MoS2

We report the direct experimental evidence of the Goos–Hänchen (GH) shift in monolayer molybdenum disulphide ( M o S 2 ) for a Gaussian beam via the quantum weak measurement scheme. We demonstrate the dependence of the GH shift in monolayer M o S 2 on the angle of incidence including the critical angle in the total internal reflection condition. We have also compared the results to the GH shift for single-layer graphene and plane glass–air interface. Our results may open up important applications of M o S 2 in optical devices and sensor industry.

Characterization of archaeological ceramics from eastern Siberia by total-reflection X-ray fluorescence spectrometry and principal component analysis

The study of the composition of archaeological ceramics provides information used to assess possible transportation routes and cultural connections between ancient people living in different regions. Total-reflection X-ray fluorescence (TXRF) was applied for the analysis of ceramics as a promising method due to the rapidity, cost-efficiency, and capability to analyze a very small amount of a sample (<20 mg), which is important for the preservation of archaeological material. Two techniques of sample preparation for the TXRF analysis of ceramics have been considered. The analysis of suspensions was applied to obtain information on the bulk composition of ceramics. Acid leaching was used for the elemental analysis of the clay component of the ceramics, with the separation of non-soluble mineral phase. The proposed TXRF techniques have been successfully validated by the analysis of reference material and comparison with independent analytical methods. Reproducibility (interlaboratory precision) was evaluated for the proposed TXRF leaching method involving two different laboratories. The application of grazing incidence X-ray fluorescence (GI-XRF) showed homogeneous distribution of elements in the specimen and correspondence of the measurements to the conditions of total external reflection. TXRF method was applied to collect the first data on the composition of archaeological samples of ceramics from Popovsky Lug, eastern Siberia (Russia). The obtained data on the elemental composition were used to classify the samples by statistical methods of analysis, including the method of principal components and factor analysis. Three different compositional groups of ceramic have been separated and accepted as corresponding to archaeological interpretation.

Design of an ultra-thin, wide-angle, stray-light-free near-eye display with a dual-layer geometrical waveguide.

The field of view (FOV) of a geometrical waveguide display is limited by the total internal reflection (TIR) condition (related with the index of glass) and the stray light generated inside the waveguide. A novel concept of an ultra-thin, wide-angle, stray-light-free, optical see-through near-eye display (NED) with a dual-layer geometrical waveguide is proposed in this paper. In the dual-layer waveguide, the two waveguides have different structures and are responsible for two different FOVs which are spliced together to form the entire FOV. The stray light of the dual-layer waveguide is analyzed and an optimized structure to suppress the stray light is designed. An optimized coupling-in structure is designed and a progressive optimization method is proposed for optimizing the illuminance uniformity of the entire FOV across the exit pupil. A dual-layer waveguide with a total thickness of 3.0 mm and stray light of less than 1% is designed. The FOV is 62° in the pupil-expanding direction, and the diameter of the exit pupil (EPD) is 10 mm at an eye relief (ER) of 18 mm. A compact projection optic is designed and finally is integrated with the dual-layer waveguide.

Goos-Hänchen shifts of Gaussian beams reflected from surfaces coated with cross-anisotropic metasurfaces

The Goos-Hänchen (GH) shift of a Gaussian beam reflected from surfaces coated with a cross-anisotropic metasurface (CM) is theoretically investigated. It is revealed that, the CM coating has influence on the spatial GH shift as well as the angular one, only at the total internal reflection condition, where the incident angle θ is above critical angle θc. Moreover, near θc, a positive or negative larger peak spatial GH shift occurs while a pair of positive and negative peaks angular GH shifts appear, compared to the case of no coating, which are induced by the CM coating. Therefore, our results may provide a feasible method to obtain a larger GH shift, and open new possibilities for applications of the CMs.

Theoretical Approach to Analysis of X-Ray Grazing-Incidence Diffraction from 2D Crystals

A theoretical formalism for quantitative description of X-ray diffraction from Langmuir monolayers under conditions of total external reflection has been developed. The proposed approach, based on the distorted-wave approximation, allows to consider physical mechanisms for plotting diffraction curves and maps (in the reciprocal space) for real monolayers and describe self-consistently specific features of Bragg peaks. The resulting algorithm can easily be implemented on a personal computer, which provides the opportunities to carry out numerical simulation of experimental two-dimensional diffraction intensity maps and determine reliably both the mean values of structural parameters of layers and their rms deviations.

On-Chip Diffraction-Free Beam Guiding beyond the Light Cone

On-chip channelless diffraction-free beam guiding enables dense integration of optical circuits in a reconfigurable manner, where total internal reflection, which is considered the cornerstone of guided-wave optics, is utilized to confine light in the out-of-plane direction. Here, we theoretically propose a physical mechanism to achieve on-chip channelless diffraction-free beam guiding beyond the light cone, utilizing the physics of bound states in the continuum. A bound state in the continuum with a tailored spatial dispersion plays an important role in cancelling both the in-plane diffraction and the out-of-plane scattering when the condition for total internal reflection is not satisfied. As a proof-of-concept verification, we experimentally demonstrate such an effect based on an all-dielectric platform using microwaves. The on-chip channelless diffraction-free beam guiding beyond the light cone also allows direct free-space coupling to such self-collimation modes. Our results may open up an avenue for exploring the physics and applications of guided-wave optics.

Electrodynamic analysis of light-assisted subnano-polishing of a quartz surface under conditions of total internal reflection by using surface profile optimization

The solution of the electrodynamic problem for determining the optimal configuration of the evanescent field formed near the rough quartz surface coated with an aqueous solution of sodium hypochlorite when illuminated from the side of quartz has been considered in order to ensure effective photochemical polishing of this surface to a sub-nanometer level of roughness. It was found that for a quartz surface profile in the form of triangular protrusions and troughs, which periodically repeat, the optimal conditions for photochemical polishing are achieved when the angle of incidence of light is critical and the height of the surface protrusions is small (up to 20 nm). It has been shown that in this case, the incident electromagnetic wave forms significantly higher values of the electric field in the protrusion region than in the trough region, creating optimal conditions for the subnano-polishing of this surface. Criteria are described for the possibility of using a regular profile in the form of protrusions and troughs of a triangular shape instead of a random surface profile characterized by a Gaussian correlation function when determining the optimal field parameters above the quartz surface.

Quantum weak measurement of Goos–Hänchen effect of light in total internal reflection using a Gaussian-mode laser beam

We report a detailed experimental demonstration of the Goos–Hänchen (GH) shift of light in total internal reflection condition for a Gaussian mode laser beam of 633 nm passing through an air-glass interface. The quantum weak measurement (QWM) technique has been exploited as a weak value amplification scheme to observe the amplified optical GH shift. The amplification of the GH shift depends on the angular deviation from the exact orthogonal position required for weak measurement. We have subsequently investigated the profiles of the beam pattern and their horizontal and vertical shifts in detail. We also show that the beam shift values obtained experimentally agree well with the theoretical results for a specific choice of angle of deviation from the orthogonal condition of weak measurement. Our results clearly demonstrate the advantages of the QWM technique for amplifying and detecting tiny optical beam shift effects and may provide important applications in precision metrology.

High-efficiency aerial display using a liquid crystal polarization grating, a retroreflector array, and a right-angle prism.

An aerial display scheme consisting of an orthogonal circular polarization grating (OCPG), a waveplate, a retroreflector array (RRA), and a right-angle prism (RAP) was developed. Because of the OCPG's functionality, retroreflected light from the RRA is transmitted through the RAP boundary surface by avoiding the total reflection condition. The proposed system can potentially increase optical throughput to 100% by designing the boundary surface incidence angle to be Brewster's angle. The scheme's feasibility was demonstrated experimentally using an OCPG and waveplate that were fabricated from polymer liquid crystal with optical anisotropy using a photoalignment technique. The scheme should be used as a type of aerial display that is compatible with polarization-diffractive elements called Pancharatnam-Berry phase elements.

Surface Plasmon Resonance of Au Thin Films Modified By Catalyst Monolayer

In this talk, we present the results and modeling o the catalyst monolayer modification effects on plasmon resonance of Au thin films. The experiments are conducted using an attenuated total reflection arrangement in which p-polarized light is incident through a prism onto a thin (-400 A) Au film deposited on the mica substrate. (Kretschmann configuration [[1]]). The angle of incidence on the base of the prism is greater than the critical angle for the prism: electrolyte interface and SPs are excited by the evanescent wave generated under these conditions of total internal reflection. The excitation is manifested by a decrease in the intensity of reflected light. The Pd monolayer on Au were electrodeposited using procedure reported by Kolbe et al [[2],[3]], while the Pt submonolayer/monolayers were deposited on Au using Surface Limited Redox Replacement (SLRR) of Pb UPD monolayer [[4]]. The plasmon resonance frequency of Au(hkl), PdML/Au(hkl) and PtML/Au(hkl) and PtSML/Au(hkl) were investigated as a function of the applied potential in the range between -0.24 V to 0.4 V vs. SCE. The comparative analysis, between Au and catalyst monolayer modified Au(hkl) samples indicate that SP resonant frequency change is induced by both; surface charge and dipole moment of the surface as well as he adsorption of H on the catalyst monolayer surface in the UPD region. The latter effect is quantified using subtractive analysis between the Au and catalyst modified Au surface and solutions with different pH. In conclusion, we present a simple model describing the catalyst monolayer effect on plasmon resonance of Au films. [1] E. Kretschmann and H. Raether, Z. Natutforsch. 23a (1968) 2135. [2] L.A. Kibler, M. Kleinert, R. Randler, D.M. Kolb, Surface Science, 443 (1999) 19. [3] J. Tang, M. Petri, L.A. Kibler, D.M. Kolb, Electrochimica Acta, 51, (2005) 125 [4] K. Sasaki et al, Electrochim. Acta, 55, (2010) 2645.

Simultaneous Measurement of γ-ray and Conversion Electron Mössbauer Spectra of Fe Films under Total Reflection Conditions Using Synchrotron Mössbauer Source

Simultaneous measurements of γ-ray and conversion electron Mossbauer spectra of Fe thin films under total reflection (TR) conditions were performed using an 57Fe synchrotron Mossbauer source. The c...

Nanofocusing Optics for an X-Ray Free-Electron Laser Generating an Extreme Intensity of 100 EW/cm2 Using Total Reflection Mirrors

A nanofocusing optical system—referred to as 100 exa—for an X-ray free-electron laser (XFEL) was developed to generate an extremely high intensity of 100 EW/cm2 (1020 W/cm2) using total reflection mirrors. The system is based on Kirkpatrick-Baez geometry, with 250-mm-long elliptically figured mirrors optimized for the SPring-8 Angstrom Compact Free-Electron Laser (SACLA) XFEL facility. The nano-precision surface employed is coated with rhodium and offers a high reflectivity of 80%, with a photon energy of up to 12 keV, under total reflection conditions. Incident X-rays on the optics are reflected with a large spatial acceptance of over 900 μm. The focused beam is 210 nm × 120 nm (full width at half maximum) and was evaluated at a photon energy of 10 keV. The optics developed for 100 exa efficiently achieved an intensity of 1 × 1020 W/cm2 with a pulse duration of 7 fs and a pulse energy of 150 μJ (25% of the pulse energy generated at the light source). The experimental chamber, which can provide different stage arrangements and sample conditions, including vacuum environments and atmospheric-pressure helium, was set up with the focusing optics to meet the experimental requirements.