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Light Modulation With The Supersonic Cell

The Jeffree cell, ~85 years ago, an early acousto-optic modulator that could be constructed in the home workshop using water or kerosene.

From US Patent 2,155,659 (Filed Feb. 27, 1935), Light Modulating Device, “This invention relates to light modulating devices such as may be used in television, sound recording and for other purposes. The present invention makes use of the principle that when high frequency mechanical waves are caused to traverse a body forming part of an optical system, they bring about general retardations and accelerations of the wave front of a beam of light passing through or reflected from the body, these retardations and accelerations corresponding to the regions of compression and rarefaction or of varying displacement of the body produced by the waves. Owing to the regular spacing of these regions, corresponding to the wavelength employed, there can be produced optical effects similar to those caused by a diffraction grating.”

“I Claim: 1. Apparatus for controlling the intensity of a beam of light in accordance with a plurality of mechanical carrier waves of different frequencies, said apparatus comprising a body capable of transmitting mechanical waves to produce diffraction grating effects, means for applying to said body a complex mechanical vibration comprising a mixture of carrier waves to cause said complex mechanical vibration to traverse said body, means for acting selectively on carrier waves of different frequencies in said mixture traversing said body to cause each of said carrier waves to follow a path in said body which is spatially separated from the paths of the others of said carrier waves and means for directing light of a beam upon the carrier waves in each of said paths to control simultaneously and independently of one another the intensity of spatially separated parts of said light beam.”

This early acousto-optic modulator technology was used in the Scophony system of mechanical television.

Just add a proper transducer and driver to the cell and begin scanning.

References:

[1] Editor, “Light modulation with the supersonic cell: a simple explanation,” Television and Short-Wave World Magazine, No. 126, Vol. 11, p. 461, August 1938.

[2] J.H. Jeffree, “The Scophony Light Control,” Television and Short-Wave World Magazine, No. 99, Vol. 9, p. 260, May 1936; British Patent 439,236 (1934).