Abstract

The use of acoustically phase-modulated coherent light is described for producing a periodic optical coherence function. A progressive acoustic wave, working as an optical phase object, converts a coherent optical wave into a periodically incoherent optical wave in the far field, which forms an array of secondary periodic incoherent sources. This array further produces a periodically partially coherent wave in its far field. These aspects are fully explained in terms of the propagation law of optical mutual intensity in the double-diffraction imaging system. A purely cosinuosoidal type of mutual intensity, consisting of three fundamental spatial-frequency components of the acoustically phase-modulated optical field, is created and ensured experimentally. Its variational depth is almost controllable with an ac electric field across the acoustic transducer. Image resolution of a double-slit object under such a periodically partially coherent illumination is discussed. The image obtained is resolved and enhanced at the double-slit separation of half of the acoustic wavelength.

© 1982 Optical Society of America

Partially coherent imaging of a periodic amplitude object with ultrasonically coherence-controllable illumination

Yoh Imai and Yoshihiro Ohtsuka
J. Opt. Soc. Am. 71(12) 1427-1433 (1981)

Modulation of optical coherence by ultrasonic waves

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Coherence requirements for partially coherent optical processing

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Partial coherence of light modulated by progressive periodic ultrasonic waves

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