• 제목/요약/키워드: Optical Interferometer

검색결과 614건 처리시간 0.037초

Accurate Roughness Measurement Using a Method for Evaluation and Interpolation of the Validity of Height Data from a Scanning White-light Interferometer

  • Kim, Namyoon;Lee, Seung Woo;I, Yongjun;Pahk, Heui-Jae
    • Current Optics and Photonics
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    • 제1권6호
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    • pp.604-612
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    • 2017

  • An effective and precise method using a scanning white-light interferometer (SWLI) for three-dimensional surface measurements, in particular for roughness measurements, has been proposed. The measurement of a microscopically sloped area using an interferometer has limitations, due to the numerical aperture of the lens. In particular, for roughness measurements, it is challenging to obtain accurate height data for a sloped area using the interferometer, due to diffraction of the light. Owing to these optical limitations of the interferometer for roughness measurements, the Ra measurements performed using an interferometer contain errors. To overcome the limitations, we propose a method consisting of the following two steps. First, we evaluate the height data and set the invalid height area to be blank, using the characteristics of the modulus peak, which has a low peak value for signals that have low reliability in the interferogram. Next, we interpolate the blank area using the adjacent reliable area. Rubert roughness standards are used to verify the proposed method. The results obtained by the proposed method are compared to those obtained with a stylus profilometer. For the considered sinusoidal samples, Ra ranges from $0.053{\mu}m$ to $6.303{\mu}m$, and we show that the interpolation method is effective. In addition, the method can be applied to a random surface where Ra ranges from $0.011{\mu}m$ to $0.164{\mu}m$. We show that the roughness results obtained using the proposed method agree well with profilometer results. The $R^2$ values for both sinusoidal and random samples are greater than 0.995.

  • https://doi.org/10.3807/COPP.2017.1.6.604 인용 PDF KSCI

Arrayed-Waveguide Grating의 경로 오차 측정을 위한 저 간섭 광원 간섭계 (Low Coherence Interferometer for Measurement of Path Length Errors in Arrayed-Waveguide Grating)

  • 송영기;허남춘;정영철
    • 한국광학회지
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    • 제15권6호
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    • pp.539-546
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    • 2004

  • 고밀도 AWG (Arrayed-Waveguide Grating)의 광 경로차 에러를 정확히 측정하기 위하여 개선된 형태의 저간섭 광원 간섭계를 구성하였고, 새로운 해석방법을 제시하였다. 소프트웨어적인 방법을 이용하여 하드웨어면에서 실험장치를 간략화할 수 있었다. 또한 인접 간섭신호들 사이의 실제 피크 위치 차이를 보간법을 이용하여 정확히 측정할 수 있다. 특정 AWG의 위상 에러를 측정하였고, 이 에러를 가정하여 계산한 파장 투과 특성이 실제 AWG의 파장투과 특성과 유사함을 보임으로써, 제시한 측정 장치의 정확성을 입증하였다.

  • https://doi.org/10.3807/KJOP.2004.15.6.539 인용 PDF KSCI