NANO- AND SUB-NANOMETER ACCURACY APPARATUS FOR CONTROLLING POSITION OF OBJECT Russian patent published in 2013 - IPC G01B11/00 G01B11/14 

FIELD: physics.

SUBSTANCE: apparatus includes a monochromatic radiation source, the output of which is superimposed with the input of a single-mode light guide which forms at the output a point monochromatic radiation source which is superimposed with the front focus of an optical system which forms a parallel light beam. Two transparent plates are placed perpendicular to the optical axis and parallel to each other. On the periphery of the first plate on the side facing the second plate, at an angle of about 120° to each other, there are three areas with surfaces inclined to the plane of the first plate. Behind the second plate there are three linear matrix photodetectors interfaced with areas of the inclined surface, wherein outputs of said photodetectors are connected to a computer. One of the plates is rigidly mounted on the control object. Areas of the inclined surface and the surface of the second plate facing each other are made with a highly reflective coating and areas of the inclined surface are made with level difference from the centre of the first plate to its edge by a value equal to at least half the wavelength of the monochromatic radiation. The lengths of the areas of the inclined surface correspond to length of operating windows of the linear matrix photodetectors.

EFFECT: increasing accuracy of determining position of one object relative the other to 0,01 nm in a short time (less than 1 mcs) in a wide range of distance between objects.

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