Abstract:
A self-referencing Mach-Zehnder interferometer for accurately measuring laser wavefronts over a broad wavelength range (for example, 600 nm to 900 nm). The apparatus directs a reference portion of an input beam to a reference arm and a measurement portion of the input beam to a measurement arm, recombines the output beams from the reference and measurement arms, and registers the resulting interference pattern ("first" interferogram) at a first detector. Optionally, subportions of the measurement portion are diverted to second and third detectors, which respectively register intensity and interferogram signals which can be processed to reduce the first interferogram's sensitivity to input noise. The reference arm includes a spatial filter producing a high quality spherical beam from the reference portion, a tilted wedge plate compensating for off-axis aberrations in the spatial filter output, and mirror collimating the radiation transmitted through the tilted wedge plate. The apparatus includes a thermally and mechanically stable baseplate which supports all reference arm optics, or at least the spatial filter, tilted wedge plate, and the collimator. The tilted wedge plate is mounted adjustably with respect to the spatial filter and collimator, so that it can be maintained in an orientation in which it does not introduce significant wave front errors into the beam propagating through the reference arm. The apparatus is polarization insensitive and has an equal path length configuration enabling measurement of radiation from broadband as well as closely spaced laser line sources.
Abstract:
A wavefront aberration sensor includes a beam splitter, one or more aberration sensor modules and a photodetector for sensing total light power. The aberration sensor modules each provide two voltage outputs from a pair of photodetectors. Differences in the voltage pairs are normalized by the total light power to represent signed aberration amplitudes of phase aberrations present in an input optical beam. The aberration amplitudes may be combined in a digital computer to provide a reconstructed wavefront.
Abstract:
A device for mapping the topography of the cornea of an eye has a light source for directing a beam of collimated monochromatic light characterized by a flat wave front onto the cornea. Positioned between the light source and the cornea is an objective lens for focusing this flat wave front toward the cornea as a converging spherical wave front. The light reflected from the cornea passes back through the objective lens to establish a reflected wave front having deviations from the flat wave front caused by aberrations on the cornea that are indicative of corneal topography. This reflected wave front is then segmentally focused by a lens array into a pattern which reveals the deviations for use in mapping the topography of the cornea.
Abstract:
PURPOSE: A wave experience device using a spring is provided to have understanding of concepts and principles of a wave by actually observing the wave of the spring. CONSTITUTION: A wave experience device using a spring includes a support (1), a spring (2), a transverse wave generator (3), a longitudinal wave generator (4), and an operation display means. The support includes a vertical support (11), a fixing frame (12), and a horizontal frame (13). The spring is in the shape of continuous coils and is horizontally extended by a wire (21) connected to the horizontal frame. The transverse wave generator includes a support pillar, a rotation pillar, a first operation pillar (31), a handle (32), and an elbow. The longitudinal wave generator includes a second operation pillar (41), a shaft (42), a switch (43), a link, and shaft housing.
Abstract:
PROBLEM TO BE SOLVED: To exclude an influence of an unnecessary light component from an analyte when measuring optical characteristics such as a shape and a wavefront aberration of the analyte.SOLUTION: Emission light emitted from a light source 101 is separated into measurement light L1 irradiating an analyte 108 and reference light L2 not irradiating the analyte, by a polarization beam splitter 103. The measurement light L1 passing the analyte is condensed on an imaging surface P by a plurality of microlenses 114a of a microlens array 114. The reference light L2 is guided to the imaging surface P by a reference light optical system 109. A computer 113 successively acquires a plurality of captured images from a CCD image sensor 116 disposed on the imaging surface P while changing an optical path length of the reference light by a moving stage 117. The computer 113 extracts an interference light spot occurring due to interference between a signal light component and the reference light, from the plurality of captured images to calculate a centroid position of the interference light spot and calculates a displacement of the centroid position from a preliminarily determined reference position.