A combined workpiece holder and calibration profile configuration (CWHACPC) is provided for integration into a surface profile measurement system. The CWHACPC may comprise at least a first calibration profile portion and a workpiece holding portion that holds a workpiece in a stable position during measurement. The first calibration profile portion comprises a plurality of reference surface regions that have known reference surface z heights or z height differences relative to one another. The first calibration profile portion and the workpiece holding portion are configured to fit within a profile scan path range of the surface profile measurement system, such that the surface profile measurement system can acquire measured surface profile data for the first calibration profile portion and the workpiece during a single pass along the profile scan path. The acquired surface profile data for the reference surface regions may be used to indicate and/or correct certain errors.

A combined workpiece holder and calibration profile configuration (CWHACPC) is provided for integration into a surface profile measurement system. The CWHACPC may comprise at least a first calibration profile portion and a workpiece holding portion that holds a workpiece in a stable position during measurement. The first calibration profile portion comprises a plurality of reference surface regions that have known reference surface z heights or z height differences relative to one another. The first calibration profile portion and the workpiece holding portion are configured to fit within a profile scan path range of the surface profile measurement system, such that the surface profile measurement system can acquire measured surface profile data for the first calibration profile portion and the workpiece during a single pass along the profile scan path. The acquired surface profile data for the reference surface regions may be used to indicate and/or correct certain errors.

The present invention discloses a real-time normalization apparatus and method of the PGC demodulation in a sinusoidal phase modulation interferometer. An optical setup containing a measuring interferometer and a monitoring interferometer is constructed. An electro-optic phase modulator is placed in the common reference arm of the two interferometers. High-frequency sinusoidal wave modulation and low-frequency triangular wave modulation are applied to the electro-optic phase modulator at the same time. Sinusoidal modulation is used for generating phase carrier, and PGC demodulation is performed to obtain quadrature signals containing the phase information to be measured. Triangular wave modulation makes the quadrature signals change periodically. Ellipse fitting is performed on the Lissajous figure corresponding to the quadrature signals, and real-time normalization of the PGC demodulated quadrature signals is achieved. By calculating the variation of the phase difference between the two interference signals, the measured displacement is obtained, and nanometer scale displacement measurement is achieved.

In part, aspects of the invention relate to methods, apparatus, and systems for intensity and/or pattern line noise reduction in a data collection system such as an optical coherence tomography system that uses an electromagnetic radiation source and interferometric principles. In one embodiment, the noise is intensity noise or line pattern noise and the source is a laser such as a swept laser. One or more attenuators responsive to one or more control signals can be used in conjunction with an analog or digital feedback network in one embodiment.

In part, aspects of the invention relate to methods, apparatus, and systems for intensity and/or pattern line noise reduction in a data collection system such as an optical coherence tomography system that uses an electromagnetic radiation source and interferometric principles. In one embodiment, the noise is intensity noise or line pattern noise and the source is a laser such as a swept laser. One or more attenuators responsive to one or more control signals can be used in conjunction with an analog or digital feedback network in one embodiment.

An interferometer system for measuring the displacement of a location of a test surface includes a reference arm comprising two reflective optical elements with optical power, a measurement arm comprising two reflective optical elements with optical power wherein one of the optical elements of the reference arm is one of the optical elements of the measurement arm. A housing can be provided in which the reflective optical elements are mounted, all such components made from a material having a low CTE. Further, spider support structures can be provided for positioning a reflective optical element within the housing, and/or for positioning a fiber optic device within the system. Light detecting elements can be installed on a side of a spider support structure facing the test surface and used to detect a tilt of the test surface which can be used to improve the accuracy of the displacement measurement.

A method for calibrating at least one optical sensor of a laser machining head is provided. The laser machining head comprises a first optical sensor, a deflection device, and a focusing device. A laser beam path of the first optical sensor passes through the deflection device and the focusing device. The method comprises the steps of: deflecting the beam path of the first optical sensor by the deflection device to a first position on a first reference; generating a first optical measurement signal based on measurement light received by the first optical sensor from the first position on the first reference; and determining a correction value for calibrating the first optical sensor based on the first optical measurement signal and according to a deviation of the first position on the first reference from a first target position, which is specified relative to a position of the machining laser beam.

One or more devices, systems, methods, and storage mediums for performing imaging, for performing measurement(s), and/or for performing or controlling detector gain or photomultiplier tube gain using one or more imaging modalities are provided herein. Examples of applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for Gastro-intestinal, cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes, catheters, capsules and needles (e.g., a biopsy needle). Devices, systems, methods, and storage mediums may include or involve a method, such as, but not limited to, for performing measurement(s) and/or controlling detector gain or photomultiplier gain, and may include or involve one or more imaging modalities, such as Optical Coherence Tomography and Fluorescence.

A system and method include a microscope with an interferometer. Another aspect of an optical microscope with interferometry includes tilting a reference mirror and/or a sample offset from a centerline of an adjacent objective or telescope lens. A further aspect provides a microscope system and method which are configured to simultaneously detect a fringe pattern with a phase-shift using light polarization in a single-shot.

A method to derive phase-coherent images with an interferometer, in situations where interferometric phase errors can be factorized into element-based terms (piston phases) is disclosed. The method is preferably implemented completely in the image domain, without resort to aperture plane measurements of visibilities, or element-based voltage complex gains.