Doppler phase-shifting digital holography and its application to surface shape measurement

Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2,Utsunomiya, Tochigi 321-8585, Japan.
Optics Letters (Impact Factor: 3.29). 05/2010; 35(10):1548-50. DOI: 10.1364/OL.35.001548
Source: PubMed


Digital holography utilizing the optical Doppler effect is proposed in which the time variation of interference fringes is recorded using a high-speed CMOS camera. The complex amplitude diffracted from the object wave is extracted by time-domain Fourier transforming the recorded interference fringes. The method was used to measure the surface shape of a concave mirror under a disturbed environment.

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    ABSTRACT: A new technique is proposed, in which a phase-shifting algorithm utilizing the optical Doppler effect and a high-speed CMOS camera are employed. In many phase-shifting algorithms, the phase distribution of the object is calculated by using a few reference phases with equal phase difference. In our proposed method, a reference mirror is moved continuously or randomly to make phase shift based on the Doppler effect. The phase distribution of the object is calculated by Fourier transforming the time-depending interference fringe data. If the reference phase shift is equally introduced to all the data points in the interference fringe image, the phase distribution at the peak frequency component in the Fourier spectrum gives the phase distribution of the object. Since a few hundred or more images were required in this method, a CMOS camera with a high frame rate of 500fps was used.
    No preview · Article · Nov 2010 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: With recent advances in high-speed computer and video capture technology, holographic films used in classical holography can be replaced with charged-coupled devices (CCD) and complementary metal-oxide-semiconductor (CMOS) image sensors to record and numerically reconstruct a hologram, which is now known as digital holography. Digital holography introduces something new to optical science. Wet chemical processing and other time-consuming procedures can be removed, so numerical recording and reconstruction can be realized in almost real time. It allows us to characterize the phase of a light field as well the intensity, and so the whole wave field can be measured and stored in a computer. Digital holography is expanding applications of holography and becoming a scientific and technological tool. Its use has now increased for measuring amplitude and the phase of object waves, displacement and three dimensional shape, particle distributions and motions, characterization of the refractive index and biological tissues, and vibration analysis, etc. Here, basic principles of digital holography for optical measurement and characterization are described. Taking into consideration the rapid advance in CCD and CMOS sensors as the background, the state-of-the-art applications of digital holography to optical measurement and characterization are presented.
    No preview · Article · Sep 2011 · Optical Engineering
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    ABSTRACT: This paper presents a method based on the use of an image sensor for obtaining the complex amplitudes of beams diffracted from an object at two different wavelengths. The complex amplitude for each wavelength is extracted by the Doppler phase-shifting method. The principle underlying the proposed method is experimentally verified by using the method with two lasers having different wavelengths to measure the surface shape of a concave mirror.
    No preview · Article · Dec 2011 · Applied Optics
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