Abstract:
In interferometer imaging signal acquisition using a movable optical beam to sample a target with specular or non specular reflecting surfaces or internal features, beam moving during interferometer signal acquisition can generate unwanted phase error due to shifting speckle field. Examples include coherent LIDAR, Interferometry Doppler sensing and optical coherence tomography. During an interferometer signal acquisition period, an interferometer sensing beam can be substantially stationary, and active step-scanning can be synchronized with interferometer signal acquisition cycles. For interferometers using repetitive chirping lasers, passive dispersive counter-scan mechanisms can be used to assist step-scanning operation.
Abstract:
A scanning monochromatic spatial low-coherent interferometer (S-LCI) can be used to simultaneously measure geometric thickness and refractive index. The probe beam of the scanning S-LCI can be an off-axis converging single wavelength laser beam, and the decomposed incident angles of the beam on the sample can be accurately defined in the Fourier domain. The angle dependent phase shift of a plane parallel plate or other sample can be obtained in a single system measurement. From the angle dependent phase shift, the geometric thickness and refractive index of the sample can be simultaneously obtained. Additionally or alternatively, the S-LCI system can interrogate the sample to profile the location and refractive index of one or more layers within the sample using the disclosed techniques.
Abstract:
High-precision monolithic optical assemblies are formed using low-cost standard optical components, such as wedge plates and/or wedge second surface mirrors. By rolling and/or shifting the components relative to each other with matched optical surfaces in contact, a precise alignment solution is found for a particular optical assembly. The resulting arrangement of components can be bonded or held together so as to form a high-precision monolithic optical assembly, which can be inserted into an optical system, according to the assembly's function. The functionality of the monolithic optical assembly can be independent of the optical system in which it is used.
Abstract:
In interferometer imaging signal acquisition using a movable optical beam to sample a target with specular or non specular reflecting surfaces or internal features, beam moving during interferometer signal acquisition can generate unwanted phase error due to shifting speckle field. Examples include coherent LIDAR, Interferometry Doppler sensing and optical coherence tomography. During an interferometer signal acquisition period, an interferometer sensing beam can be substantially stationary, and active step-scanning can be synchronized with interferometer signal acquisition cycles. For interferometers using repetitive chirping lasers, passive dispersive counter-scan mechanisms can be used to assist step-scanning operation.
Abstract:
Calibration of an arbitrary spectrometer can use a stable monolithic interferometer as a wavelength calibration standard. Light from a polychromatic light source is input to the monolithic interferometer where it undergoes interference based on the optical path difference (OPD) of the interferometer. The resulting wavelength-modulated output beam is analyzed by a reference spectrometer to generate reference data. The output beam from the interferometer can be provided to an arbitrary spectral instrument. Wavelength calibration of the arbitrary spectral instrument may then be performed based on a comparison of the spectral instrument output with the reference data. By appropriate choice of materials for the monolithic interferometer, a highly stable structure can be fabricated that has a wide field and/or is thermally compensated. Because the interferometer is stable, the one-time generated reference data can be used over an extended period of time without re-characterization.
Abstract:
In an optical fiber system for delivering laser, a laser beam is focused onto an optical fiber at an injection port of the system. The end portions of the fiber have cladding treatments to attenuate stray light and cladding mode light, so as to enhance the protection of the outer layer joint points. Photodetector sensors monitor scattered stray light, cladding mode light, and/or transmitted cladding mode light. Sensor signals are provided to a control unit for analyzing the fiber coupling performance. If need be, the control unit can control a laser shutter or the like to minimize or prevent damage. In materials processing applications, the photodetector signals can be analyzed to determine the processing status of a work piece.
Abstract:
A scanning monochromatic spatial low-coherent interferometer (S-LCI) can be used to simultaneously measure geometric thickness and refractive index. The probe beam of the scanning S-LCI can be an off-axis converging single wavelength laser beam, and the decomposed incident angles of the beam on the sample can be accurately defined in the Fourier domain. The angle dependent phase shift of a plane parallel plate or other sample can be obtained in a single system measurement. From the angle dependent phase shift, the geometric thickness and refractive index of the sample can be simultaneously obtained. Additionally or alternatively, the S-LCI system can interrogate the sample to profile the location and refractive index of one or more layers within the sample using the disclosed techniques.
Abstract:
High-precision monolithic optical assemblies are formed using low-cost standard optical components, such as wedge plates and/or wedge second surface mirrors. By rolling and/or shifting the components relative to each other with matched optical surfaces in contact, a precise alignment solution is found for a particular optical assembly. The resulting arrangement of components can be bonded or held together so as to form a high-precision monolithic optical assembly, which can be inserted into an optical system, according to the assembly's function. The functionality of the monolithic optical assembly can be independent of the optical system in which it is used.
Abstract:
In an optical fiber system for delivering laser, a laser beam is focused onto an optical fiber at an injection port of the system. The end portions of the fiber have cladding treatments to attenuate stray light and cladding mode light, so as to enhance the protection of the outer layer joint points. Photodetector sensors monitor scattered stray light, cladding mode light, and/or transmitted cladding mode light. Sensor signals are provided to a control unit for analyzing the fiber coupling performance. If need be, the control unit can control a laser shutter or the like to minimize or prevent damage. In materials processing applications, the photodetector signals can be analyzed to determine the processing status of a work piece.