Abstract: An optical inspection system includes a polarizing isolator that reduces error in measurements by preventing ghost light reflected or scattered from element of a detection subsystem from re-entering the illumination and detection optical paths. The polarizing isolator may include a polarizing splitter that isolates light directionally according the a linear polarization state and two quarter-wave plates for transforming linearly polarized light to circularly polarized light.

Abstract: An optical inspection system includes a polarizing isolator that reduces error in measurements by preventing ghost light reflected or scattered from element of a detection subsystem from re-entering the illumination and detection optical paths. The polarizing isolator may include a polarizing splitter that isolates light directionally according the a linear polarization state and two quarter-wave plates for transforming linearly polarized light to circularly polarized light.

Abstract: An optical surface inspection system provides dark-field detection avoiding ghost images and without capturing, stray, reflected or re-scattered light. The system includes an illumination system that generates an illumination spot on a surface under inspection collecting lens that collects substantially all light scattered from the surface under inspection from the illumination spot. The system also includes a light guide with a first end having a numerical aperture matched to an exit aperture of the collecting lens and a field of view matched to the illumination spot, and a second end coupled to a detector.

Abstract: An optical measuring system includes a scatterometer in which an illumination beam is provided through an aperture in a lens used to collect light for the scattering detection. The void may be a slit in the lens, a missing portion along an edge of the lens, or another suitable void. Another detection channel may be provided to detect light returning through the void in the collecting lens, for example, a profilometer may be implemented by detecting interference between reflected light returning along the illumination path and light from the illumination source.

Abstract: An optical inspection system includes a fluorescence channel that detects fluorescent behavior (or lack thereof) of artifacts present on a surface under inspection and at least one other optical channel for determining a characteristic of the surface under inspection in an illuminated spot. The other optical channel may be a height measuring channel, such as an interferometric channel or a deflectometric channel, the other optical channel may be a scatterometric channel, or both height measurement and scatterometry may be employed in combination as a three channel system. The presence of absence of fluorescent behavior may be used to correct assumptions about or determine a type of artifact detected by scatterometry, and may be used to correct the polarity of a height measurement made by a height-measuring channel.

Abstract: An optically efficient and thermally stable solar heating apparatus and method provide efficient heating by using a solar collector having a transparent tube containing a porous absorbent material or structure that permits liquid or aerosol to percolate through the transparent tube. Thermal protection against overheating is provided when the system is drained by a transparent top with a bottom surface that, when in contact with another liquid medium filling the collector, permits incident light to enter and be collected, but when the liquid medium that normally contacts the bottom surface of the top is absent when the system is drained, incident light is reflected. The collector, top and transparent tubes may be extruded and made from the same recyclable plastic material, making the assembly lightweight for installation and ease of structural integration, while facilitating recyclability of the entire collector.

Abstract: A scatterometer-interferometer and method for detecting and distinguishing characteristics of surface artifacts provides improved artifact detection and increased scanning speed in interferometric measurement systems. A scatterometer and interferometer are combined in a single measurement head and may have overlapping, concentric or separate measurement spots. Interferometric sampling of a surface under measurement may be initiated in response to detection of a surface artifact by the scatterometer, so that continuous scanning of the surface under measurement can be performed until further information about the size and/or height of the artifact is needed.

Abstract: A scatterometer-interferometer and method for detecting and distinguishing characteristics of surface artifacts provides improved artifact detection and increased scanning speed in interferometric measurement systems. A scatterometer and interferometer are combined in a single measurement head and may have overlapping, concentric or separate measurement spots. Interferometric sampling of a surface under measurement may be initiated in response to detection of a surface artifact by the scatterometer, so that continuous scanning of the surface under measurement can be performed until further information about the size and/or height of the artifact is needed.

Abstract: A resonant ellipsometer and method for determining ellipsometric parameters of a surface provide an efficient and low-cost mechanism for performing ellipsometric measurements. A surface of interest is included as a reflection point of a resonance optical path within a resonator. The intersection of the resonance optical path with the surface of interest is at an angle away from normal so that the complex reflectivity of the surface alters the phase of the resonance optical path. Intensity measurements of light emitted from a partially reflective surface of the resonator for orthogonal polarizations and for at least two effective cavity lengths provide complete information for computing the ellipsoidal parameters on the surface of interest. The resonator may be a Fabry-Perot resonator or a ring resonator. The wavelength of the illumination can be swept, or the cavity length mechanically or electronically altered to change the cavity length.

Abstract: A Fabry-Perot resonator apparatus and method including an in-resonator polarizing element improves detection/measurement sensitivity of an optical system, provides both fields at a single end of the resonator, and overcomes other structural and performance limitations of particular optical systems. A polarizing element, which may be a quarter-wave plate, a 45-degree Faraday rotator or other polarizing element capable of converting between linear and circular polarizations and back, is placed in the resonance path of the Fabry-Perot resonator. The polarizing element effectively doubles the cavity length and orthogonally isolates forward from reverse reflection rays within the resonator, eliminating interference between rays and providing isolated bright and dark fields at each end of the resonator.

Abstract: A Fabry-Perot resonator apparatus and method for observing low reflectivity surfaces provides functional improvements for optical inspection and measurement systems, optical storage and retrieval systems as well as other optical systems when the a surface of interest in the resonator path has a lower than ideal reflectivity. The Fabry-Perot resonator is designed with an angle of incidence on the surface of interest deviating from normal incidence, effectively raising the reflectivity. Resonance is supported either by one or more reflectors oriented at angles with respect to the surface of interest, or by a focusing system that alters the directive angle of optical path(s) within the resonator such that the angle of incidence at an intersection of the optical path with the surface of interest is an angle other than normal. A normal incidence is maintained at the reflector(s), so that resonance is supported between the surface of interest and the reflector(s).

Abstract: Apparatus for sensing information regarding a surface including a first plurality of optical elements arranged to acquire two dimensional information about a surface, a second plurality of optical elements arranged to acquire topographical information about the surface, wherein the first plurality and the second plurality of optical elements are arranged to simultaneously provide the two dimensional information and the topographical information to at least partially non-overlapping portions of a single sensor array.

Abstract: A three-dimensional imaging resonator and method therefor provides improved surface height measurement capability in optical measuring systems. A resonator including a surface of interest in a resonant image path is coupled to an external multi-pixel detector that detects an image of intensity of light reflected from or transmitted through the resonator. An imaging system is included in the resonator to image a region of a surface of interest on another reflector forming part of the resonator. By changing an effective cavity length of the resonator, the image is “scanned” in a direction perpendicular to the other reflector and a processing system stores information corresponding to resonance peaks to achieve a mapping of feature height above the surface of interest. The resonator effective cavity length can be changed by sweeping the illumination wavelength or by mechanically or otherwise altering the optical length of the resonator.

Abstract: A resonator method and system for distinguishing characteristics of surface features or contaminants provides improved inspection or surface feature detection capability in scanning optical systems. A resonator including a surface of interest in the resonant path is coupled to a detector that detects light leaving the resonator. Changes in the resonance peak positions and peak intensities are evaluated against known changes for standard scatters in order to determine the material characteristics of an artifact at the surface of interest that causes a resonance change. The lateral size of the artifact is determined by de-convolving a known illumination spot size with the changing resonance characteristics, and the standard scatterer data is selected in conformity with the determined artifact size.

Abstract: A three-dimensional imaging resonator and method therefor provides improved surface height measurement capability in optical measuring systems. A resonator including a surface of interest in a resonant image path is coupled to an external multi-pixel detector that detects an image of intensity of light reflected from or transmitted through the resonator. An imaging system is included in the resonator to image a region of a surface of interest on another reflector forming part of the resonator. By changing an effective cavity length of the resonator, the image is “scanned” in a direction perpendicular to the other reflector and a processing system stores information corresponding to resonance peaks to achieve a mapping of feature height above the surface of interest. The resonator effective cavity length can be changed by sweeping the illumination wavelength or by mechanically or otherwise altering the optical length of the resonator.

Abstract: A resonator method and system for distinguishing characteristics of surface features or contaminants provides improved inspection or surface feature detection capability in scanning optical systems. A resonator including a surface of interest in the resonant path is coupled to a detector that detects light leaving the resonator. Changes in the resonance peak positions and peak intensities are evaluated against known changes for standard scatters in order to determine the material characteristics of an artifact at the surface of interest that causes a resonance change. The lateral size of the artifact is determined by de-convolving a known illumination spot size with the changing resonance characteristics, and the standard scatterer data is selected in conformity with the determined artifact size.

Abstract: A Fabry-Perot resonator apparatus and method including an in-resonator polarizing element improves detection/measurement sensitivity of an optical system, provides both fields at a single end of the resonator, and overcomes other structural and performance limitations of particular optical systems. A polarizing element, which may be a quarter-wave plate, a 45-degree Faraday rotator or other polarizing element capable of converting between linear and circular polarizations and back, is placed in the resonance path of the Fabry-Perot resonator. The polarizing element effectively doubles the cavity length and orthogonally isolates forward from reverse reflection rays within the resonator, eliminating interference between rays and providing isolated bright and dark fields at each end of the resonator.

Abstract: A resonant ellipsometer and method for determining ellipsometric parameters of a surface provide an efficient and low-cost mechanism for performing ellipsometric measurements. A surface of interest is included as a reflection point of a resonance optical path within a resonator. The intersection of the resonance optical path with the surface of interest is at an angle away from normal so that the complex reflectivity of the surface alters the phase of the resonance optical path. Intensity measurements of light emitted from a partially reflective surface of the resonator for orthogonal polarizations and for at least two effective cavity lengths provide complete information for computing the ellipsoidal parameters on the surface of interest. The resonator may be a Fabry-Perot resonator or a ring resonator. The wavelength of the illumination can be swept, or the cavity length mechanically or electronically altered to change the cavity length.

Abstract: A Fabry-Perot resonator apparatus and method for observing low reflectivity surfaces provides functional improvements for optical inspection and measurement systems, optical storage and retrieval systems as well as other optical systems when the a surface of interest in the resonator path has a lower than ideal reflectivity. The Fabry-Perot resonator is designed with an angle of incidence on the surface of interest deviating from normal incidence, effectively raising the reflectivity. Resonance is supported either by one or more reflectors oriented at angles with respect to the surface of interest, or by a focusing system that alters the directive angle of optical path(s) within the resonator such that the angle of incidence at an intersection of the optical path with the surface of interest is an angle other than normal. A normal incidence is maintained at the reflector(s), so that resonance is supported between the surface of interest and the reflector(s).

Abstract: Apparatus for sensing information regarding a surface including a first plurality of optical elements arranged to acquire two dimensional information about a surface, a second plurality of optical elements arranged to acquire topographical information about the surface, wherein the first plurality and the second plurality of optical elements are arranged to simultaneously provide the two dimensional information and the topographical information to at least partially non-overlapping portions of a single sensor array.