Transparency Effect Research Articles

FOCMS: An ultrafast optical clearing method with quantified analysis

Optical clearing technology offers a prospective solution to improve the imaging depth and quality of optical microscopy, but there is still a lack of quantitative standards to accurately evaluate transparency effects so the composition and concentration of most reagents are not optimal. Here, we propose a transparency quantitative analysis method (TQAM) based on the tissue area recognition technique to achieve the high-throughput reagent concentration gradient screening. After optimizations of reagent composition, concentration, operation time and other parameters of the optical clearing, we develop a new ultrafast optical clearing method with quantified analysis (FOCMS) with excellent transparency effect, simple operation, improved imaging depth and quality, minor morphological change and outstanding fluorescence retention. Applied the FOCMS to an application of human brain tissue, significant differences are observed between glioma and normal human brain tissue, while these differences are difficult to be found without the assistance of FOCMS. Therefore, FOCMS shows great application potential in clinical diagnosis and treatment, pathological analysis and so on.

Self-induced transparency in a perfectly absorbing chiral second-harmonic generator

Transparency and perfect absorption are two contradictory terms; a perfect absorber never permits waves to transmit through. However, this statement only remains true in the linear regime, where the nonlinearity has been omitted and the physical system like the perfect absorber is not affected by the incoming waves. Here we experimentally demonstrate an intriguing self-induced transparency effect in a perfectly absorbing optical microcavity, which perfectly absorbs any incoming waves at the low power level, but allows a portion of waves to be transmitted at the higher power due to the nonlinear coupling between the fundamental and its second harmonic modes. Moreover, the asymmetric scattering nature of the microcavity enables a chiral and unidirectional reflection in one of the input ports, this leads to asymmetric and chiral coherent control of the perfect absorption states through phase varying. More importantly, such chiral behaviors also empower the chiral emission of second-harmonic generation with a high distinct ratio in the transparency state. These results pave the way for controllable transparency in a wide range of fields in optics, microwaves, acoustics, mechanics, and matter waves.

Coherent brightening of a multilayer MQW− structure taking into account resonant tunneling for ultra-short IR pulses in a transverse electric field

The features of the effect of self-induced transparency (SIT) in a multi-well M Q W − structure with two working levels in quantum wells (QWs) in a transverse electric field are considered. The cycle of energy exchange between an ultrashort pulse and the resonant medium of two-level systems, which leads to coherent bleaching of the M Q W − structure, is complicated by resonant tunneling between the size-quantization levels of neighboring QWs. The behavior of a radiation pulse during the propagation of two-level QWs in a resonant medium in the self-transparency regime is analyzed. Analytical dependences of various branches of evolution and possible transition conditions between branches for propagating pulses are demonstrated. Practical possibilities are pointed out for deforming the envelope profile and the duration of the radiation pulse by varying the strength of the applied external electric field. The direct possibility for such controlled manifestations of the SIT effect as propagation without absorption, pulse delay, and variation of the observability threshold is emphasized. • The features of the self-induced transparency (SIT) effect in a multi-well MQW-structure with two working levels in quantum wells (QWs) are considered. • The structure is placed in a transverse electric field directed perpendicularly to the vertical walls of the QW, which ensures that the ground level of one well coincides with the energy of the excited level of the neighboring well. • The cycle of energy exchange between an ultra-short pulse and the resonant medium of two-level system is complicated by the processes of resonant tunneling between the quantum-confinement levels of neighboring QWs. • The behavior of a radiation pulse during propagation of two-level QWs in a resonant medium is analyzed taking into account resonant tunneling between neighboring QWs in the self-transparency mode.

Origami-inspired frequency selective surface with large bandwidth modulation range based on electromagnetically induced transparency effect

Origami-inspired frequency selective surface with large bandwidth modulation range based on electromagnetically induced transparency effect

Multi-control plasmon-induced transparency via graphene and bulk Dirac semimetal

Based on graphene and bulk Dirac semimetal (BDS), we proposed a terahertz metamaterial which can realize plasmon-induced transparency (PIT) effect. By independently or jointly tuning the Fermi energy of graphene and BDS, the frequency selection, single frequency optical switch and the double frequency synchronous optical switch can be achieved. The physical mechanism of single PIT effect is explained via electric field distribution and coupled mode theory. In addition, we improve the proposed metamaterial by etching grooves on the BDS gratings and changing the structural parameters of graphene and BDS gratings, which results in a dual-PIT effect. When independently or jointly tuning the Fermi energy of graphene and BDS, the frequency of the dual-PIT peaks can also be tuned, and the quatary frequency asynchronous and triple frequency synchronous optical switch can be achieved. By analyzing the electric field distribution, we found that the double PIT effect is caused by different mode coupling between graphene and BDS gratings. This work provides a new direction for the future design of multi-band filters and optical switch in terahertz band.

Does Transparency Effect on The Participation of Student’s Parent in Education Provisions?

The low transparency and participation of parents in providing education at State Elementary Schools is the background to prove whether or not there is a direct effect of transparency in the dimensions of information availability, accuracy of media use and ease of access to information on school management on the participation of parents in SDN education. The aims of this study is to analyze the effect of transparency on the participation of parents in education. The unit of research analysis is the school committee management, totaling 2867 people. With Slovin's formula, 348 samples were selected randomly. Through the use of the causal expost facto method, data was collected using a questionnaire in the form of an attitude scale as outlined in the google form and manual questionnaire. Analyzed with descriptive statistical techniques and parametric inferential statistics, which was preceded by a normality test using the Lilifors technique. Regression significance test and regression linearity test were performed and analyzed using path analysis techniques. The results of the statistical test concluded that there is no direct effect of the availability of school management information on the participation of parents in the provision of education; there is no direct effect of the accuracy of the school management information media on the participation of parents in the administration of education, accessibility of school management information on the participation of parents in the provision of education. The availability of management information in schools has a significant direct effect on information accessibility.

Versatile terahertz graphene metasurface based on plasmon-induced transparency

A monolayer terahertz graphene metasurface is designed to achieve tunable plasmon-induced transparency (PIT) effect in two perpendicular polarization directions based on surface plasmon polariton resonance. The penta-frequency and dual-frequency switch can be easily implemented by adjusting the Fermi levels of graphene, and the switch has excellent performances including modulation degree of amplitude (81.4 % < MDA < 97.1 %) and insertion loss (0.01 dB < IL < 0.04 dB). Moreover, the metasurface has high sensitivity, which can be up to 30500 nm/RIU. Also, the designed PIT metasurface has a good slow light effect, and group indexes are respectively 1100 and 2396 corresponding to x-polarized and y-polarized light. This work demonstrates that graphene metasurface has potential applications in switch, sensor and slow-light devices.

The transparency paradox: When transparency cues helps or backfires for brands?

Prior research indicates that transparency of Corporate Social Responsibility (CSR) claims increases consumers' positive reactions to the firm. However, this article suggests that this effect depends on the interplay between transparency cues (presence vs. absence) and brand strength (small vs. large). Our set of experimental studies examine the effect of information transparency and brand strength on consumers' purchasing intentions toward fashion products. Findings indicate a surprising effect of transparency cues: while its presence improves consumers' responses to CSR of small brands, it reduces consumers’ outcomes towards large brands. Results also suggest that trust mediates the effects since transparency cues boost consumers' trust toward small (vs. large) brands. This research further suggests that greenwashing practices as a boundary condition of transparency effects, since CSR communication with an honest (vs. greenwashing) focus fosters the transparency effects. The findings have important implications for effective CSR strategies in the fashion industry.

A giant self-Kerr nonlinearity using phase-sensitive excitation in a closed three-level atomic system

A third-order nonlinear response is investigated theoretically using a closed lambda system. In this scheme, a pair of optical fields and a microwave field connect three hyperfine levels in a cyclic fashion, rendering the atomic response sensitive to the relative phase of all three fields. Changing the relative phase, we can suppress the linear response of the probe field and enhance its third order self-Kerr nonlinear response using the underlying electromagnetically induced transparency (EIT) effect. The resultant giant self-Kerr nonlinear response is comparable to or exceeding that found in atomic systems at room temperature. Most importantly, we show that the self-Kerr nonlinear response at an optical frequency can be controlled using the phase and amplitude of a frequency-separated microwave field.

Polarization multiplexed electromagnetically induced transparency metasurface based on VO2 with high-performance sensing application

A vanadium dioxide (VO2) based dielectric metasurface is proposed to realize polarization multiplexed electromagnetically induced transparency (EIT) effect with tunability. In the near-infrared regime, distinct transparency windows with high transmission intensity and quality factor (Q-factor) can be observed under the excitation of two orthogonal polarized lights. By changing the conductivity of VO2, the EIT peak intensity and the group delay of the incident light can be manipulated dynamically. Meanwhile, the narrow transparency window is extremely sensitive to the change of the surrounding refractive index, and the proposed metasurface exhibits high sensitivity and figure of merits in both x- and y-polarization conditions. Therefore, the proposed dielectric metasurface based on VO2 provides a new method for dynamically controlled EIT effects in the near-infrared region and inspires potential applications in optical modulations, tunable slow light devices, and high-performance refractive index sensors, etc.

Tunable Electromagnetically Induced Transparent Window of Terahertz Metamaterials and Its Sensing Performance

The electromagnetically induced transparency effect of terahertz metamaterials exhibits excellent modulation and sensing properties, and it is critical to investigate the modulation effect of the transparent window by optimizing structural parameters. In this work, a unilateral symmetrical metamaterial structure based on the cut-wire resonator and the U-shaped split ring resonator is demonstrated to achieve electromagnetically induced transparency-like (EIT-like) effect. Based on the symmetrical structure, by changing the structural parameters of the split ring, an asymmetric structure metamaterial is also studied to obtain better tuning and sensing characteristics. The parameters for controlling the transparent window of the metamaterial are investigated in both passive and active modulation modes. In addition, the metamaterial structure based on the cut-wire resonator, unilateral symmetric and asymmetric configurations are investigated for high performance refractive index sensing purposes, and it is found that the first two metamaterial structures can achieve sensitivity responses of 63.6 GHz/RIU and 84.4 GHz/RIU, respectively, while the asymmetric metamaterial is up to 102.3 GHz/RIU. The high sensitivity frequency response of the proposed metamaterial structures makes them good candidates for various chemical and biomedical sensing applications.

Dynamic modulation of dual plasmon-induced transparency based on coupled graphene grating-sheets

We propose to achieve dual plasmon-induced transparency effects through the couplings between a bright mode and two dark modes in a metamaterial system with two graphene sheets separated by periodic graphene gratings. We find that both the number and the positions of the transparent windows can be modulated by tuning the Fermi energy and coupling distance between graphene resonators, which allows us to design a high-efficiency switch with an on/off state modulation amplitude of 71.1%. A three-particle model-based theoretical model is applied to explain the simulated results and excellent agreement between them is found.

Dynamically tunable multiband plasmon-induced transparency effect based on graphene nanoribbon waveguide coupled with rectangle cavities system

A dynamically tunable multiband plasmon-induced transparency (PIT) effect in a series of rectangle cavities coupled with a graphene nanoribbon waveguide system is investigated theoretically and numerically by tuning the Fermi level of the graphene rectangle cavity. A single-PIT effect is realized using two different methods: one is the direct destructive interference between bright and dark modes, and the other is the indirect coupling through a graphene nanoribbon waveguide. Moreover, dual-PIT effect is obtained by three rectangle cavities side-coupled with a graphene nanoribbon waveguide. Results show that the magnitude of the dual-PIT window can be controlled between 0.21 and 0.74, and the corresponding group index is controlled between 143.2 and 108.6. Furthermore, the triple-PIT effect is achieved by the combination of bright–dark mode coupling and the cavities side-coupled with waveguide mechanism. Thus, sharp PIT windows can be formed, a high transmission is maintained between 0.51 and 0.74, and the corresponding group index is controlled between 161.4 and 115.8. Compared with previously proposed graphene-based PIT effects, the size of the introduced structure is less than 0.5 μm2. Particularly, the slow light effect is crucial in the current research. Therefore, a novel approach is introduced toward the realization of optical sensors, optical filters, and slow light and light storage devices with ultra-compact, multiband, and dynamic tunable.

In Vivo Evaluation of the Effects of Sintering Temperature on the Optical Properties of Dental Glass-Ceramics.

In prosthodontics, the ability of glass-ceramics to express the optical properties of natural teeth is an important goal of esthetic restorations. Dental restorations do not merely need to be similar in color to natural teeth; proper optical properties, such as opalescence, transparency, etc., must be combined in order to achieve excellent esthetic effects. The optical properties of ceramic materials are mainly distinguished by different hues (e.g., A, B, C, and D) combined with translucency (e.g., high translucency (HT), medium translucency (MT), low translucency (LT), and medium opacity (MO)). However, there are many varieties of tooth color. Therefore, it is expected that glass-ceramics can change their nanocrystal size and porosity through different heat-treatment temperatures and times and, thereby, present different transparency effects. This study mainly analyzed the influence of changes in sintering temperature on the optical properties of glass-ceramics. The optical properties of glass-ceramics in the oral cavity were evaluated with human trials. We hypothesized that (1) the transparency of glass-ceramics can be changed by controlling the sintering temperature and (2) glass-ceramics modified by the sintering temperature can be suitable for clinical applications. Results showed that the transparency decreased, the nanoparticle size increased, the crystallinity increased, and the surface hardness decreased as the sintering temperature increased. High-brightness glass-ceramics have more-sensitive optical properties. Results of clinical trials showed that glass-ceramics whose transparency was changed by controlling the sintering temperature can be candidates for clinical applications. Based on the above results, the hypotheses of this study were supported. In the future, we will continue to explore the esthetic field of dental restorations.

Guiding-mode-assisted double-BICs in an all-dielectric metasurface.

The electromagnetically induced transparency (EIT) effect realized in a metasurface is potential for slow light applications for its extreme dispersion variation in the transparency window. Herein, we propose an all-dielectric metasurface to generate a double resonance-trapped quasi bound states in the continuum (BICs) in the form of EIT or Fano resonance through selectively exciting the guiding modes with the grating. The group delay of the EIT is effectively improved up to 2113 ps attributing to the ultrahigh Q-factor resonance carried by the resonance-trapped quasi-BIC. The coupled harmonic oscillator model and a full multipole decomposition are utilized to analyze the physical mechanism of EIT-based quasi-BIC. In addition, the BIC based on Fano and EIT resonance can simultaneously exist at different wavelengths. These findings provide a new feasible platform for slow light devices in the near-infrared region.

Detecting the transverse spin density of light via electromagnetically induced transparency.

For light that is transversely confined, its field vector spins in a plane not orthogonal to the propagation direction, leading to the presence of transverse spin, which plays a fundamental role in the field of chiral quantum optics. Here, we theoretically propose a scheme to detect the transverse spin density (TSD) of light by utilizing a multilevel atomic medium. The scheme is based on the electromagnetically induced transparency effect, which enables the TSD-dependent modulation of the susceptibility of the atomic medium by using a coupling field whose TSD is to be detected. The modulated susceptibility results in a spin-dependent absorption for a probe beam passing through the atomic medium. We show that there exists a corresponding relationship between the TSD distribution of the coupling field and the polarization distribution of the transmitted probe beam through a theoretical study of two typical cases, in which the coupling field is provided by a tightly focused field and a two-beam interference field, respectively. Based on this relationship, the key features of the TSD of the coupling field, such as the spatial distribution, the symmetry property, and the spin-momentum locking, can be inferred from the transmitted probe beam. Benefiting from the fast response of the atomic medium to the variation of the coupling field, the present scheme is capable of detecting the TSD in real time, offering new possibilities for developing transverse-spin-based techniques.

Unified model for plasmon-induced transparency with direct and indirect coupling in borophene-integrated metamaterials.

We propose, both numerically and theoretically, a uniform model to investigate the plasmonically induced transparency effect in plasmonic metamaterial consisting of dual-layer spatially separated borophene nanoribbons array. The dynamic transfer properties of light between two borophene resonators can be effectively described by the proposed model, with which we can distinguish and connect the direct and indirect coupling schemes in the metamaterial system. By adjusting the electron density and separation of two borophene ribbons, the proposed metamaterials enable a narrow band in the near-infrared region to reach high transmission. It provides a new, to the best of our knowledge, platform for optoelectronic integrated high-performance devices in the communication band.

Trapping a free-propagating single-photon into an atomic ensemble as a quantum stationary light pulse

Efficient photon–photon interaction is one of the key elements for realizing quantum information processing. The interaction, however, must often be mediated through an atomic medium due to the bosonic nature of photons, and the interaction time, which is critically linked to the efficiency, depends on the properties of the atom–photon interaction. While the electromagnetically induced transparency effect does offer the possibility of photonic quantum memory, it does not enhance the interaction time as it fully maps the photonic state to an atomic state. The stationary light pulse (SLP) effect, on the contrary, traps the photonic state inside an atomic medium with zero group velocity, opening up the possibility of enhanced interaction time. In this work, we report the first experimental demonstration of trapping a free-propagating single-photon into a cold atomic ensemble via the quantum SLP (QSLP) process. We conclusively show that the quantum properties of the single-photon state are preserved well during the QSLP process. Our work paves the way for new approaches for efficient photon–photon interactions, exotic photonic states, and many-body simulations in photonic systems.

Triple-band electromagnetically induced transparency effects enabled by two sets of arc-ring-type resonators at terahertz frequency

A new type of terahertz metamaterial resonance device with triple-band electromagnetically induced transparent (EIT) is introduced in this paper. Its unit cell consists of two sets of arc-ring-type resonators placed on a dielectric sheet, which can generate three EIT transparency peaks at terahertz region. The generation of these transparent peaks is mainly attributed to the coupling effect between the resonant modes of the arc-ring-type resonators. Influence of the arc length and radius of the arc-ring-type resonators and the width of the air layer between the inner arc-ring-type resonators and outer arc-ring-type resonators on the transmission spectrum is studied. Furthermore, active tunability of the transparent peaks is achieved by incorporating photosensitive silicon with tunable conductivity in the metamaterial structure. The results show that depending on the change of conductivity as well as the position of photosensitive silicon, the EIT effect can be shown as an adjustable switch from triple-band to dual-band or from triple-band to single-band. In addition, the refractive index sensing performance of the metamaterial device is discussed. The metamaterial device has the excellent characteristics of simple structure design and active modulation, which are important and useful for the development of photoelectric switches, sensors and filter devices.

Tunable narrow transparency windows induced by the coupled quasi-guided modes in borophene plasmonic nanostructure

A grating-assisted triple-layer continuous borophene sheets structure is presented to investigate the phase-coupled plasmon-induced transparency (PIT) effect at the near-infrared communication band. In the proposed structure, the diffraction grating is utilized to couple the normal incident waves, which excites the quasi-guided mode in triple-layer continuous borophene sheets. Compared to the patterned structure, the requirement of complicated processing techniques and extra doping configurations for tuning carrier density can be avoided by using the continuous borophene sheet. Additionally, the narrower transparency windows are shown in the spectral responses via the phase coupling between two detuned quasi-guided modes with high quality factors. The transparency windows can be efficiently tuned by adjusting the carrier densities in borophene sheets or the separation distances between the borophene sheets. The analytical results based on temporal coupled mode theory and transfer matrix method are consistent with the numerical simulations via finite-difference time-domain calculations. The proposed scheme provides the promising design of a tunable PIT component that is compatible with optical communication technology.