- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Electro-optical Amplitude and Phase Modulators Based on Tunable Guided-Mode Resonance Effect
摘要： Here, electrically tunable amplitude and phase modulators are designed by the hybridization of indium tin oxide (ITO) into a guided-mode resonance mirror (so-called GMRM) which consists of a high-index silicon (Si) nanograting placed on top of a Si guiding core followed by a silicon-dioxide optical buffer layer and a highly reflective substrate. The physical mechanism is based on the intriguing optical characteristics of GMRMs and integration of a dual-gated ITO with the capability of charge carrier modulation into the Si nanograting. A gate-tunable amplitude modulator with a modulation depth as high as ≈0.80 is realized by careful selection of structural parameters, excitation of a strongly coupled guided-mode resonance, and modifying the external bias voltage. This design can also be adjusted only by changing the thickness of its optical buffer layer and moderating the strength of the guided-mode resonance to serve as an efficient active phase modulator. The phase variation of ≈210° and relatively high reflection amplitude in 0.45-0.6 range are accomplished when the applied bias voltage alters from -15 V to +24 V. This reflection phase tuning mainly originates from the carrier depletion and accumulation inside the incorporated 5 nm-thick ITO layer. The accurate modeling and numerical calculation of optical response of the proposed unit cell for different applied external voltages are carried out through linking the electrostatics device physics model and rigorous coupled wave analysis (RCWA) optical simulation. The design rules and physical principles behind the dual-gated ITO-integrated GMRM unit cell are discussed in-depth by investigation of the structural parameters, the nature of supported resonances, and voltage-dependent effects of inhomogeneous carrier distributions in both ITO and Si layers. The electrical addressability and individual control over pixelated subwavelength unit cells provide the opportunity for realizing an actively reconfigurable metasurface with the desired gradient phase delay.
关键词： metasurfaces,phase and amplitude modulators,electro-optical materials,silicon,guided-mode resonance,indium tin oxide,All-dielectric
更新于2025-09-23 15:19:57
-
Silicon-Organic Hybrid Photonic Devices in a Photonic Integrated Circuit Technology
摘要： In this work, we present recent results on the hybrid integration of electro-optical organic materials in a photonic integrated circuit (PIC) technology. We review some of the identi?ed challenges regarding process compatibility and present experimental results on the integration of organic materials in a PIC technology using a 0.25 μm SiGe BiCMOS pilotline. Here, we are focusing on electro-optical applications toward high-speed modulators with ultra-low energy consumption.
关键词： photonic integrated circuit,high-speed modulators,electro-optical materials,silicon-organic hybrid,ultra-low energy consumption
更新于2025-09-16 10:30:52
-
Direct observation and simultaneous use of linear and quadratic electro-optical effects
摘要： We report on the direct observation and simultaneous use of the linear and quadratic electro-optical effect and propose a method by which higher-order susceptibilities of electro-optical materials can be determined. The evaluation is based on the separation of the second- and third-order susceptibilities and the experimental technique uses a slot waveguide ring resonator fabricated in an integrated photonic circuit technology, which is embedded by a guest-host polymer system consisting of the azobenzene dye disperse red 1 in a poly(methyl methacrylate) matrix as active electro-optical material. The contribution of both effects on the electro-optical response under the influence of static and time-varying electrical fields is investigated. We show that the quadratic electro-optical effect has a significant influence on the overall electro-optical response even with acentric molecular orientated molecules. Our findings have important implications for developing electro-optical devices based on polymer-filled slot waveguides and give rise to advanced photonic circuits.
关键词： higher-order susceptibilities,electro-optical materials,quadratic electro-optical effect,slot waveguide,ring resonator,linear electro-optical effect
更新于2025-09-12 10:27:22
-
Growth of large-size high-quality ZnTe bulk crystals by traveling solvent melting zone method
摘要： ZnTe crystal is a promising electro-optical crystal materials applied for THz generation and detection. However, there is still a big challenge to obtain large sized high quality ZnTe crystals. In this work, large sized ZnTe bulk crystals with Φ30 mm × 150 mm were grown by the traveling solvent melting zone (TSMZ) method. With the characterization of the optical and electrical properties of as-grown ZnTe crystals, the band gap (2.22 eV), high IR transmittance (around 60%), high resistivity (3.5×103 ??cm), low density (1.3×105 cm-2) and small sizes (3μm - 5 μm) of Te inclusions in ZnTe crystals, low etch pit densities (1.5×105 cm-2), high peak intensity to FWHM ratio (2.5×104) of the LO peak in the Raman spectra were obtained. Furthermore, the THz transmission spectra was measured and the maximum transmittance is more than 40% at the range of 0.3 - 3THz. Based on these results, high quality and large aspect ratio ZnTe bulk crystals can be obtained by the TSMZ technique. Our work has greatly facilitated the application of ZnTe crystals in THz device.
关键词： terahertz,ZnTe,traveling solvent melting zone,electro-optical materials
更新于2025-09-10 09:29:36