Masaaki Oshita
| Department of Mechanical and Intelligent Systems Engineering | Assistant Professor |
| Cluster II (Emerging Multi-interdisciplinary Engineering) | Assistant Professor |
Researcher Information
Career
Educational Background
- Apr. 2019 - Present
The University of Electro-Communications, Graduate School of Informatics and Engineering, Department of Mechanical and Intelligent Systems Engineering, Japan - Apr. 2017 - Mar. 2019
The University of Electro-Communications, Graduate School of Informatics and Engineering, Department of Mechanical and Intelligent Systems Engineering, Japan - Apr. 2013 - Mar. 2017
The University of Electro-Communications, Faculty of Informatics and Engineering, Department of Mechanical Engineering and Intelligent Systems, Japan
Research Activity Information
Award
- Apr. 2023
電気学会
プラズモニック超小型分光素子のための静電変調機構
センサ・マイクロシステム部門大会優秀論文発表賞, 大下雅昭 - Jan. 2022
文部科学省ナノテクノロジープラットフォーム
プラズモニック構造を利用したシリコンMEMSモノリシック赤外SPR分光センサ
令和3年度「秀でた利用成果」最優秀賞受賞課題, 菅 哲朗;大下 雅昭;安永 竣;澤村 智紀;Eric Lebrasseur;藤原 誠;岡本 有貴;水島 彩子;宇佐美 尚人;肥後 昭男;太田 悦子;三田 吉郎 - Nov. 2021
一般社団法人 電気学会 センサマイクロマシン部門
プラズモニック超小型分光素子の波長分解能の評価
電気学会センサ・マイクロマシン部門 部門大会 第38回 「センサ・マイクロマシンと応用システム」 シンポジウム 五十嵐賞・奨励賞ファイナリスト, 大下 雅昭;山本 陽介;齋藤 史朗;菅 哲朗 - Oct. 2020
一般社団法人 電気学会 センサマイクロマシン部門
表面プラズモン共鳴式光検出器を用いた近赤外分光法によるガス検出
電気学会センサ・マイクロマシン部門 部門大会 第37回 「センサ・マイクロマシンと応用システム」 シンポジウム 五十嵐賞・奨励賞ファイナリスト, 山本 陽介;大下雅昭;深澤真啓;斎藤史朗;菅哲朗 - Oct. 2018
日本機械学会
近赤外域を対象としたプラズモン光検出型分光法
第9回マイクロ・ナノ工学シンポジウム 若手優秀講演フェロー賞, 出納優, 大下雅昭, Gaulier Thomas, 安食嘉晴, 菅哲朗 - Oct. 2018
日本機械学会
プラズモニック金回折格子を備えた振動MEMSによる近赤外分光器
第9回マイクロ・ナノ工学シンポジウム 若手優秀講演表彰, 大下雅昭;高橋英俊;菅哲朗
Paper
- Optimizing geometry and metal-dependent performance of Si-based Schottky plasmonic photodetectors
Eslam Abubakr; Ashenafi Abadi; Masaaki Oshita; Shiro Saito; Tetsuo Kan
Optical Materials, Elsevier BV, 150, 115175-115175, Apr. 2024, Peer-reviwed
Scientific journal, English - Characterization of an uncooled mid-infrared Schottky photodetector based on a 2D Au/PtSi/p-Si nanohole array at a higher light modulation frequency
Ashenafi Abadi; Eslam Abubakr; Masaaki Oshita; Daiji Noda; Ryo Ohta; Tetsuo Kan
Applied Optics, Optica Publishing Group, 63, 8, 2046-2046, 04 Mar. 2024, Peer-reviwed, In this study, an uncooled 2D nanohole array PtSi/p-Si Schottky mid-infrared (MIR) photodetector, which is essential for on-chip Si-based low-barrier MIR detectors, is presented. Room temperature operation introduces susceptibility to thermal noise and can impact stability. Through modulation frequency and reverse bias optimization, the stability improved by 7 times at 170 Hz and −3.5V, respectively. The effective light detection and stability were confirmed through ON/OFF response measurements over a longer time. The wavelength-dependent responsivity, measured with a tunable MIR laser, confirmed the responsiveness of the device in the MIR region of 2.5 µm to 4.0 µm, with a maximum specific detectivity (D*) of 2.0×103cmHz1/2W−1 at 3.0 µm; this result shows its potential applicability for noninvasive human lipid monitoring. Overall, this study focuses on the crucial role of signal analysis optimization in enhancing the performance of MIR photodetectors at room temperature.
Scientific journal - Spectroscopy for Continuous Light with a Submicron Grating Mems Cantilever Plasmonic Photodetector
Yuki Kaneda; Masaaki Oshita; Abubakr Eslam; Shiro Saito; Tetsuo Kan
2024 IEEE 37th International Conference on Micro Electro Mechanical Systems (MEMS), IEEE, 21 Jan. 2024, Peer-reviwed
International conference proceedings, English - Near-infrared gas spectroscopy based on plasmonic photodetector applied for multiple gas species
Utana Yamaoka; Yuuki Kaneda; Masaaki Oshita; Shiro Saito; Tetsuo Kan
Japanese Journal of Applied Physics, IOP Publishing, 63, 1, 012004-012004, 01 Jan. 2024, Peer-reviwed, Abstract
We proposed a NIR spectroscopy system that measures multiple types of gases using a plasmonic photodetector. We formed a gold diffraction grating on a silicon substrate to create a plasmonic photodetector and conducted gas spectral measurements in the NIR region. As a result, we could measure the transmission spectrum of water vapor gas at a concentration of 2%. Furthermore, we could measure ethanol gas transmittance at different concentrations of 4.5% and 2.7%, and change in transmission depending on concentration. Lastly, the transmission spectrum of 10% NH3 gas was measured. Since these results are consistent with evaluations using Fourier transform IR spectroscopy, it was confirmed that the proposed gas measurement can be applied to multiple types of gas sensing.
Scientific journal, English - Detection of backside coupled propagating surface plasmon resonance on the sidewall of a wafer
M. Oshita; S. Suzuki; K. Masamoto; T. Kan
Lead, AIP Advances, AIP Publishing, 13, 11, 01 Nov. 2023, Peer-reviwed, We proposed a surface plasmon resonance (SPR) sensor structure that utilized a glass wafer with a diffraction grating and an n-type silicon piece bonded near the SPR coupling site. This configuration enabled surface plasmon excitation from the back of the substrate without the unwanted interaction between the excitation light and the sample, and electrical detection of the SPR response by a 0.7-eV Schottky barrier at the Au/n-Si interface formed on the sidewall of the silicon piece was achieved. Experimental evaluation of the surface plasmon coupling performance was conducted, showing clear peaks in the photocurrent for various wavelengths in the NIR-II window, ranging from 1100 to 1300 nm. The device’s ability to detect propagating surface plasmons as a photocurrent was confirmed; the results indicated a consistent trend with theoretical and numerical calculations. Since the device was composed of a glass substrate, the use of wavelengths shorter than the near-infrared wavelength was possible, including visible wavelengths where the optical absorption by water is negligible. Thus, our proposed sensor provides a compact and efficient solution for SPR sensing in aqueous solutions.
Scientific journal, English - Si Plasmonic MEMS devices for infrared sensing
菅哲朗; Elyas Ashenafi ABADI; 大下雅昭
日本赤外線学会誌, 33, 1, 13, Aug. 2023, Invited
Scientific journal, Japanese - Electromechanically reconfigurable plasmonic photodetector with a distinct shift in resonant wavelength
Masaaki Oshita; Shiro Saito; Tetsuo Kan
Lead, Microsystems & Nanoengineering, Springer Science and Business Media LLC, 9, 1, 09 Mar. 2023, Peer-reviwed, Abstract
Plasmonic photodetectors have received increasing attention because their detection properties can be designed by tailoring their metal structures on surfaces without using any additional components. Reconfiguration of the plasmonic resonant state in a photodetector is relevant for various applications, including investigating in situ adaptive detection property changes, depending on the situation, and performing single-pixel spectroscopy in geometrically limited regions. However, the spectral responsivity change with conventional reconfiguration methods is relatively small. Here, we propose a plasmonic photodetector that reconfigures its spectral responsivity with electromechanical deformation instead of bias tuning. The photodetector consists of a gold plasmonic grating formed on an n-type silicon cantilever, and the spectral responsivity is reconfigured by electromechanically scanning at an incident angle to the grating on the cantilever. The photodetector exhibits peak shifts in spectral responsivity in a wavelength range from 1250 to 1310 nm after electromechanical reconfiguration. Finally, for potential future applications, we demonstrate near-infrared spectroscopy using the photodetector. This photodetector has the potential to be adopted as a near-infrared spectrometer in industrial silicon imaging systems because its structure enables subbandgap photodetection on silicon by a Schottky junction.
Scientific journal, English - Unique Dispersion Relation for Plasmonic Photodetectors with Submicron Grating
Yuki Kaneda; Masaaki Oshita; Utana Yamaoka; Shiro Saito; Tetsuo Kan
2023 IEEE 36th International Conference on Micro Electro Mechanical Systems (MEMS), IEEE, 15 Jan. 2023, Peer-reviwed
International conference proceedings - Grating-Based Surface Plasmon Resonance Sensor for Visible Light Employing a Metal/Semiconductor Junction for Electrical Readout
Ryota Kuroki; Shinichi Suzuki; Shun Yasunaga; Masaaki Oshita; Tetsuo Kan
IEEE Sensors Journal, Institute of Electrical and Electronics Engineers (IEEE), 22, 23, 22557-22563, 01 Dec. 2022, Peer-reviwed
Scientific journal - RECONFIGURABLE PLASMONIC PHOTODETECTOR INTEGRATED WITH ELECTROSTATIC ACTUATOR FOR SPECTROMETRY
Masaaki Oshita; Shiro Saito; Tetsuo Kan
2022 IEEE 35TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS CONFERENCE (MEMS), IEEE, 959-962, Feb. 2022, Peer-reviwed, Miniaturized spectrometers enable spectrometry on limited space, and they have been actively studied for various applications. Although various methods have been proposed to miniaturize spectrometer, conventional spectrometer consist of multiple filters and photodetectors, which limits the reduction of the footprint. Here, we report a reconfigurable plasmonic photodetector integrated with electrostatic actuator for spectrometry. In this paper, we investigated whether spectroscopy is possible using this structure in wavelength range from 1240 nm to 1310 nm. The simplicity of this structure presents potential to be adapted in micro-spectrometers.
International conference proceedings, English - Near-Infrared Spectroscopic Gas Detection Using a Surface Plasmon Resonance Photodetector with 20 nm Resolution
Yosuke Yamamoto; Masaaki Oshita; Shiro Saito; Tetsuo Kan
ACS Applied Nano Materials, American Chemical Society (ACS), 4, 12, 13405-13412, 24 Dec. 2021, Peer-reviwed, This paper reports on gas sensing based on near-infrared (NIR) reconstructive spectroscopy using a surface plasmon resonance (SPR) photodetector. The reconstructive spectrometer consists of an Au grating structure on an n-type silicon substrate. When the Au grating is irradiated with transverse magnetic polarized light, SPR emerges at different incident angles for each wavelength, producing an electric current via the Schottky barrier at the Au/n-type Si interface. The irradiated light spectrum can be derived by analyzing the relationship between the incident angle and the current. The proposed reconstructive spectrometer presented a 20 nm wavelength resolution in the NIR region. NIR light absorption appeared at approximately 1392 nm in the 1.5% ethanol gas spectrum by the SPR photodetector, which is coherent with Fourier transform infrared spectroscopy, indicating that the proposed reconstructive spectrometer is applicable to gas measurements.
Scientific journal, English - Reconstructive Spectrometer Based on Plasmonic Schottky Photodetector with MEMS Angular Modulator
Masaaki Oshita; Yosuke Yamamoto; Shiro Saito; Tetsuo Kan
Lead, 2021 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), IEEE, 1118-1121, 20 Jun. 2021, Peer-reviwed, Reconstructive spectrometers are intensively attracting attention because it reduces the size of a spectrometer. Reconstructive spectrometers, however. must have multiple photodetectors which have different photoresponse spectrum from each other. Here, we report a reconstructive spectrometer using a single plasmonic photodetector with a MEMS angular modulator. Using unique angular characteristic of plasmonic photodetector, incident spectrum can be reconstructed using signal of one photodetector, In this paper, we investigated spectrometer performance using the plasmonic photodetector in wavelength range from 1230 nm to 1330 nm, and its wavelength resolution was derived. The simplicity of this structure presents potential to be adapted in micro spectrometers.
International conference proceedings, English - MEMSによるシリコンを用いた光デバイス：赤外線センサや可変フィルタの展開
安永竣; 大下雅昭; 菅哲朗
ケミカルエンジニヤリング, 65, 12, 747-754, Dec. 2020, Invited
In book, Japanese - 光を操るシリコンプラズモンアンテナMEMS技術
安永 竣; 古澤 岳; 大下 雅昭; 菅 哲朗
応用物理, 89, 11, 651-655, Nov. 2020, Invited
Scientific journal, Japanese - Gas Detection by Near-Infrared Spectroscopy Based on a Surface Plasmon Resonance Photodetector
Yosuke Yamamoto; Masaaki Oshita; Masahiro Fukasawa; Shiro Saito; Tetsuo Kan
2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS), IEEE, 204-207, Jan. 2020, Peer-reviwed, This paper reports a gas detection method by near-infrared (NIR) spectroscopy using a Surface Plasmon Resonance photodetector (SPR) equipped with an Au grating on a n-Si substrate. The photodetector can detect light of a specific wavelength as photocurrent at a corresponding incident angle. The spectrum of incident light can be obtained from the photocurrent by examining the responsivity of each wavelength of the photodetector in advance, we fabricated the photodetector and measured the absorption spectrum of ethanol gas in the NIR laser using the photodetector, and absorption around lambda=1390 nm was observed.
International conference proceedings, English
Lectures, oral presentations, etc.
- 機械的変調が可能なプラズモニック光検出構造を用いたMEMS分光素子
大下雅昭
Japanese, 第29回医用近赤外線分光法研究会・第27回酸素ダイナミクス研究会, Invited
28 Oct. 2023 - Si Plasmonic MEMS device for infrared sensing
Masaaki Oshita; Elyas Ashenafi Abadi; Tetsuo Kan
Invited oral presentation, English, 13th International Conference on Metamaterials, Photonic Crystals and Plasmonics (META2023), Invited
18 Jul. 2023
18 Jul. 2023- 21 Jul. 2023 - NANO-WIDTH ZIGZAG FLEXURE STRUCTURES FOR HIGHLY TUNABLE GRATING PITCH
Atsuya Kiryu; Gaku Furusawa; Oshita Masaaki; Tetsuo Kan
Poster presentation, English, The 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2023), Peer-reviewed
25 Jun. 2023- 29 Jun. 2023 - NEAR-INFRARED GAS SPECTROSCOPY BASED ON PLASMONIC PHOTODETECTOR APPLIED FOR MULTIPLE GAS SPECIES
Utana Yamaoka; Masaaki Oshita; Yuuki Kaneda; Shiro Saito; Tetsuo Kan
Poster presentation, English, The 22nd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2023), Peer-reviewed
25 Jun. 2023- 29 Jun. 2023 - プラズモニック分光素子による物質スペクトルの測定
齊藤 伊吹; 金田 裕喜; 山岡 詩菜; 大下 雅昭; 齋藤 史郎; 菅 哲朗
日本機械学会 関東支部 講演会
16 Mar. 2023- 17 Mar. 2023 - SIDE WALL DETECTION TYPE SPR SENSOR WITH GOLD GRATING ON GLASS
Masaaki Oshita; Shinichi Suzuki; Kazuto Masamoto; Tetsuo Kan
Poster presentation, English, The 36th International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2023), Peer-reviewed
Jan. 2023 - プラズモニック光検出器を用いた分光法による複数種のガス計測
山岡 詩菜; 金田 裕喜; 齋藤史朗; 大下 雅昭; 菅 哲朗
第13回マイクロ・ナノ工学シンポジウム
14 Nov. 2022- 16 Nov. 2022 - プラズモニック分光素子による連続スペクトルの分光の研究
金田 裕喜; 大下 雅昭; 山岡 詩菜; 齋藤 史郎; 菅 哲朗
第13回マイクロ・ナノ工学シンポジウム
14 Nov. 2022- 16 Nov. 2022 - 白色光源を用いた表面プラズモン共鳴式光検出器による分光の研究
金田裕喜; 大下 雅昭; 山岡 詩菜; 齋藤 史郎; 菅 哲朗
ロボティクス・メカトロニクス 講演会 2022
01 Jun. 2022- 04 Jun. 2022 - プラズモニック超小型分光素子の波長分解能の評価
大下雅昭; 山本陽介; 齋藤史朗; 菅哲朗
第38回「センサ・マイクロマシンと応用システム」シンポジウム
09 Nov. 2021- 11 Nov. 2021
Research Themes
- 神経伝達物質計測のための表面プラズモン共鳴型化学量センサプローブの開発
大下 雅昭
日本学術振興会, 科学研究費助成事業, 電気通信大学, 若手研究, 24K17596
Apr. 2024 - Mar. 2026 - 脳へ埋込可能なプラズモン型化学センサによる神経ペプチド計測
公益財団法人 島津科学技術振興財団, 研究開発助成金, Principal investigator
Apr. 2024 - Mar. 2026 - 脳内に埋め込み可能な表面プラズモン共鳴型化学量センサの研究
大下 雅昭
日本学術振興会, 科学研究費助成事業 研究活動スタート支援, 電気通信大学, 研究活動スタート支援, 22K20404
Aug. 2022 - Mar. 2024 - Ultra-compact spectrometer using propagating plasmon on gold grating
大下 雅昭
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows, The University of Electro-Communications, Grant-in-Aid for JSPS Fellows, 本研究は金回折格子上の伝搬型プラズモンをショットキー障壁によって検出する構造を利用した超小型分光器の実現を目的とする。研究課題実施前までにプラズモンを利用し、MEMS上での分光が原理上可能であることを示した。しかし、得られたスペクトルに大きな誤差が含まれる問題があった。これは、どの回折次数をもつプラズモンも同一の検出器で検出するため、解となるスペクトルが一意に定まらないことに起因する。 2021年度は、この問題点に関してまず単一の回折次数のみを取りうる走査範囲において分光器の信号を計測することでスペクトルの誤差が解消されるか検証を行った。まず、本研究の分光器をバルクマイクロマシニング技術で試作し、理論的に求めた分散関係から求めた入射角の走査範囲において音圧で分光器の構造を共振させた。可変波長光源から近赤外光を分光器に照射し、分光器が出力する信号を記録してそこから入射スペクトルを計算した。信号から逆算したスペクトルは市販の分光器（Sol2.2A, BWTEK社）によって得られた結果と比較し、本課題で問題としていたスペクトルの大きな誤差が解消されていることを確認した。次に分光器がMEMSモジュール化可能か検証するために、静電力によって分光器の片持ち梁を駆動する検証を行ったところ、約5 [deg]の入射角走査範囲が得られた。この範囲の大きさは波長と角度走査範囲を対応づける分散関係より、この分光器は約100 [nm]の分光可能な波長範囲を持つことがわかった。現在は、伝搬型SPRがもつ回折次数の符号が正の場合と負の場合で伝搬方向が異なる原理を用いてそれぞれを分離して検出する構造の設計及び試作に取り組んでいる。, 21J13187
Apr. 2021 - Mar. 2023