[3분논문] 제15회 - 광역학적 초소형 가속도 측정장치

황용섭의 3분논문 제15회입니다.

지난회에 이어 이번회에도 시작과 끝에 배경음악을 넣어 보았습니다.

총시간은 3분 16초입니다.

재미있게 들어보세요.

# 방송 바로 듣기

1. 15_3분논문_제15회.mp3

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팟캐스트 검색: "3분논문"

팟캐스트 주소: http://itunes.apple.com/us/podcast/3bunnonmun/id568397433

RSS 피드: http://www.iblug.com/xml/itunes/3minpaper.xml

# 논문표지

# 간단한 정보

글쓴이: Alexander G. Krause, Martin Winger, Tim D. Blasius, Qiang Lin and Oskar Painter

제목: A high-resolution microchip optomechanical accelerometer

학술지: Nature Photonics

발행년월: 2012년 10월

이어가기: http://dx.doi.org/10.1038/nphoton.2012.245

# 용어

- accelerometer: 가속도 측정장치.

# 발췌

1.

Here, we demonstrate an optomechanical accelerometer that makes use of ultrasensitive

displacement readout using a photonic-crystal nanocavity monolithically integrated with a nanotethered test mass of high mechanical Q-factor13. 

2. 

the optical transmission through the photonic-crystal cavity is monitored using an evanescently coupled fibre-taper waveguide24 anchored to the rigid side of the cavity.

# 그림

Figure 1: Overview of accelerometer design.

c, False-coloured SEM image of a typical optomechanical accelerometer. A test mass with dimensions of 150 µm × 60 µm × 400 nm (green) is suspended on highly stressed 150-nm-wide and 560-μm-long SiN nanotethers, which allow for high oscillator frequencies (>27 kHz) and high mechanical Q-factors (>10⁶). On the upper edge of the test mass, a zipper photonic-crystal nanocavity (pink) is implemented. The cross-shaped cuts on the test mass facilitate undercutting the device. d, Zoom-in of the optical cavity region showing the magnitude of the electric field |E(r)| for the fundamental bonded mode of the zipper cavity. The top beam is mechanically anchored to the bulk SiN and the bottom beam is attached to the test mass. e, Schematic displacement profile (not to scale) of the fundamental in-plane mechanical mode used for acceleration sensing. 

Figure 2: Experimental system and noise data.

a, Laser light used to probe the zipper cavity motion is split with a beamsplitter; the signal arm is sent through a fibre polarization controller (FPC) and a fibre taper, which is coupled to the optical cavity, while the other arm is sent directly to a balanced photodetector (BPD). Variable optical attenuators (VOA) in each arm balance the powers, and a power meter (PM) is used to calibrate the probe power. The BPD signal is sent to a proportional-integral controller (PI), locking the laser half a linewidth red-detuned from the optical resonance. The sample is mounted on a shake table comprising a shear piezo. Transduced accelerations are measured using either an electronic spectrum analyser (ESA) or a lock-in amplifier. 

# 결론

광결정을 이용한 공진기를 써서 광역학적으로 좋은 성능의 가속도 측정기를 구현했다는 점에서 의미가 있다. 

끝. 

2012년 11월 4일