• Title/Summary/Keyword: Laser-Interferometer

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150 nm Pitch Measurement using Metrological AFM (길이 소급성을 갖는 AFM을 이용한 150nm 피치 측정)

  • ;I. Misumi;S. Gonda;T. Kurosawa
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.264-267
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    • 2003
  • Pitch measurements of 150 nm pitch one-dimensional grating standards were carried out using an contact mode atomic force microscopy(C-AFM) with a high resolution three-axis laser interferometer. It was called as 'Nano-metrological AFM' In Nano-metrological AFM, Three laser interferometers were aligned well to the end of AFM tip. Laser sources of the three-axis laser interferometer in the nano-metrological AFM were calibrated with an I$_2$-stablilzed He-Ne laser at a wavelength of 633 nm. So, the Abbe error was minimized and the result of the pitch measurement using the nano-metrological AFM has a traceability to the length standard directly. The uncertainty in the pitch measurement was estimated in accordance with the Guide to the Expression of Uncertainty in Measurement(GUM). The Primary source of uncertainty in the pitch-measurements was derived from repeatability of pitch-measurement, and its value was approx 0.186 nm. Expanded uncertainty(k=2) of less than 5.23 nm was obtained. It is suggested that the metrological AFM is a useful tool for the nano-metrological standard calibration.

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A Study on a Laser Scanning Vibrometer Using a Magnetostrictive Resonant Device (자기 변형 공진 기구를 이용한 레이저 스캐닝 진동측정기에 관한 연구)

  • 이정화;류제길;박기환
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.58-66
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    • 1998
  • A low power consuming laser scanning vibrometer is studied for its development. For its optical system, a laser interferometer is constructed to use the Doppler effect. In order to reduce the driving power of the scanning system, a small displacement of the scanning system is produced, which is achieved by using a magnetostrictive actuator. A sufficient rotating angle of the scanning system is obtained by using an amplified displacement from the resonant phenomena of a second order mechanical system composed of a mass and spring. The control of the magnetostrictive actuator using a Terfenol-D is performed without using a feedback system to help reduce the power consumption. The vibration analysis is made for the sinusoidal scanning input to have the space domain information from the time domain of the velocity of a vibration object. As a partial work of development of a tow power consuming laser scanning vibrometer, in this work, a scanning system which has the above features is developed and experimentally investigated. For the purpose of the optical system calibration, the vibration measurement for one axis is presented and the future works are discussed.

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Precise Position Control of a Linear Stage with I/Q heterodyne Interferometer Feedback

  • Moon, Chan-Woo;Lee, Sung-Ho;Chung, J.K.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1142-1146
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    • 2004
  • The ultra precision linear stage is an essential device in the fields of MEMS and Bio technology. A piezo electric motor is widely used for its better linear characteristics, faster response time, and smaller size than conventional electro-magnetic actuator. We develop a new inchworm type motor to implement an actuator-integrated a long stroke linear stage which can move fast. To implement a servo system, we use a heterodyne interferometer as a position sensor, and we propose a new measurement technique using I/Q demodulator, and we propose a counting method to measure the position of fast moving object with low cost circuitry. The characteristics of the actuator and servo system are evaluated by measuring its displacement with a commercial laser interferometer.

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Nano-scale high-accuracy displacement measurement using the Michelson laser interferometer controlled with a feedback circuit (되먹임 회로로 제어하는 Michelson 레이저 간섭계를 이용한 Nano-scale 미세변위 측정)

  • Ahn, Seong-Joon;Oh, Tae-Sik;Ahn, Seung-Joon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1007-1012
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    • 2007
  • A novel Michelson interferometer controlled with a feedback circuit(MIFC) has been developed and its performance has been evaluated. This new interferometer can measure the displacement of the sample by directly reading the feedback bias applied to the PZT whose piezoelectric characteristic is known. The experimental result showed that the step height the silicon membrane measured by using MIFC was actually same with the value measured by SEM, which confirms that MICS is an easy and accurate method for the nano-scale displacement measurement.

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Exciting Frequency Detection of Latticed fence Structure Using Fiber Optic Interferometer Sensor (간섭계형 광섬유 센서를 이용한 격자형 구조물의 외부 가진 진동수 탐지)

  • 이종길
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.5
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    • pp.142-148
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    • 2004
  • In this paper, to detect exciting frequency on the latticed fence structure, fiber optic sensor using Sagnac interferometer was fabricated and tested. The latticed structure fabricated with dimension of 180 cm wide and 180 cm high, the optical fiber, 50 m in length, distributed and fixed on the latticed structure. Single mode fiber, a laser with 1,550 m wavelength, and $3{\times}3$ coupler were used. Excited vibration signal applied to the latticed structure from 200 Hz to 1 KHz. The detected optical signals were compared to the detected acceleration signals and analyzed on the time and frequency domain. Based on the experimental results, fiber optic sensor using Sagnac interferometer detected exciting frequency, effectively. This system can be applied to the structural health monitoring system.