Pacific Light & Hologram, Inc.

David Joseph Harper

Jonathan Seamus Blackley

Kamran Qaderi

Methods, apparatus, devices, subsystems, and systems for optical measurements are provided, e.g., precise measurement of a geometry of an element such as an angle of an object, a refractive index of a substance, or surface roughness of an uneven surface. In one aspect, a method includes: illuminating light on an object having a first surface extending along a first direction and a second surface extending along a second direction different from the first direction, capturing an interference pattern between a first light beam reflected from the first surface and a second light beam reflected from the second surface, and determining an angle between the first direction and the second direction based on a result of Fourier transform of the captured interference pattern.

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Ames, IA, United States of America

David Joseph Harper