Tohoku University · 공학
이 교수의 연구실은 광학 및 탄소소재 기반의 나노광학 기술을 핵심으로 하며, 특히 CMOS 유연한 통합 광소자, 플라즈몬릭 나노구조, 메타물질 기반의 탄성 제어 가능한 THz 소자, 그리고 나노입자 운반 기반의 나노광학 장치를 중심으로 연구를 진행하고 있습니다. 고성능 광웨이브가이드, 초소형 편광 필터, EIT 유사 메타물질, 그리고 파장 제어 기반의 입자 이송 시스템 등 응용 중심의 혁신적 설계를 통해 통합 광전자 및 나노광학 분야의 기술적 한계를 극복하고자 합니다. 특히, 실리콘 기반 광학 플랫폼과 MEMS 기반의 가변성 메타물질을 접목한 연구로, 차세대 통신 및 센서 기술의 핵심 기반을 마련하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
We demonstrated a low-loss CMOS-compatible multi-layer platform using monolithic back-end-of-line (BEOL) integration. 0.8dB/cm propagation loss is measured for the PECVD Si₃N₄ waveguide at 1580nm wavelength. The loss is further reduced to 0.24dB/cm at 1270nm wavelength, justifying the platform's feasibility for O-band operation. An inter-layer transition coupler is designed, achieving less than 0.2dB/transition loss across 70nm bandwidth. This is the lowest inter-layer transition loss ever repor
An ultra-compact broadband TE-pass polarizer was proposed and demonstrated on the silicon-on-insulator (SOI) platform, using the horizontal nanoplasmonic slot waveguide (HNSW). Detailed design principle was presented, taking advantage of the distinct confinement region of the TE and TM modes in the HNSW. TM mode cut-off could be achieved when waveguide width was below 210 nm. Proof-of-concept devices were subsequently fabricated in a CMOS-compatible process. The optimized device had an active re
Electromagnetically induced transparency (EIT) analogs in classical oscillator systems have been investigated due to their potential in optical applications such as nonlinear devices and the slow-light field. Metamaterials are good candidates that utilize EIT-like effects to regulate optical light. Here, an actively reconfigurable EIT metamaterial for controlling THz waves, which consists of a movable bar and a fixed wire pair, is numerically and experimentally proposed. By changing the distance
We propose a plasmonic nano-optical conveyor belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles with a higher degree of precision and flexibility. Graded nano-rods with individual dimensions coded to have resonance at specific wavelengths are incorporated along the waveguide in order to produce spatially addressable hot spots. Consequently, by switching the excitation wavelength sequentially, particl
Abstract Terahertz (THz) waves have attracted extensive attention recently owing to their spectral specificity and transmission properties. For developing THz technologies, filters are significant devices because they can manipulate waves transmission. Metamaterials (MMs) possess unique optical characteristics that are not available in natural materials, have been developed for THz filters. However, reported MMs with separated units only excite plasmonic resonances, which limits their applicatio
A new periodic Al groove structure coated by SiO<sub>2</sub> thin film is designed and numerically investigated for wide-angle and polarization-insensitive broadband absorption. A metal groove array presents optical absorption enhancement due to the cavity mode resonance, with the absorption peak capable of being shifted by controlling the depth of the metal groove. Broadband absorption can be realized by a periodic array of metal grooves with different depths combined in one single period. A tw
A polarization splitter and rotator that supports simultaneous O-, C-, and L-band operation is first experimentally demonstrated, with record 1-dB bandwidth over 360 nm, high fabrication tolerance, and high TE-TM conversion efficiency of −0.33 dB.
We numerically demonstrate the scheme of independent optofluidic switching of nanoparticles on a silicon-based lab-on-a-chip system, using an electronic logic activated ring-assisted Mach-Zehnder interferometer (RAMZI). By using the carrier injection method with a tiny refractive index change of 8.00×10<sup>-4</sup> to adjust the phase delay of a ring resonator sitting on one arm of the MZI, the light passing through could be switched to any output port of MZI followed by a directional coupler (
We experimentally demonstrate a microelectromechanically reconfigurable ladder-shaped metamaterial (LS-MM) operating in a terahertz (THz) range. Ultrasmall cantilever actuators with a beam length of 14 μm are employed to independently reshape each unit cell of the LS-MM, correspondingly switching the transmission response of THz waves. The microelectromechanically driven LS-MM achieves a tuning contrast of 60.1% in transmittance at 0.78 THz and a 0.9-rad delay in the transmission phase shift at
Abstract An antireflection (AR) structure that incorporates a subwavelength grating (SWG) is a promising candidate for suppressing the Fresnel reflection of a silicon prism used as a component of an injection-seeded THz wave parametric generator (is-TPG) to improve the efficiency in extracting THz waves. Here, a two-dimensional binary AR-SWG with a 20 μ m period is designed and then numerically and experimentally realized. The measured transmittance of the AR-SWG is discovered to be greater than
Hydrogen is a crucial element for crystalline silicon solar cells due to its ability to passivate bulk defects in silicon. The introduction and distribution of hydrogen has gained a lot of interest due to its proposed involvement in the phenomenon termed “light and elevated temperature induced degradation” (LeTID) in multicrystalline silicon (mc-Si) solar cells. LeTID, which can cause an efficiency loss of about 6-14% (relative) for mc-Si PERC (passivated emitter and rear cell) devices upon expo