Abstract: An optical head for confocal microscopy that is especially advantageous for measurements on thick samples is provided. An interface between the optical head and the sample is index matched, to avoid beam aberration at this interface. The optical head includes a window having a convex surface facing away from the sample, so that light beams crossing this convex surface do so at or near normal incidence and are therefore not significantly aberrated. The window is rotationally symmetric about an axis perpendicular to the interface between the head and the sample. The head also includes at least two optical fibers, which can be used for input and/or output. Beams passing to and/or from the fibers are collimated by collimators. A single focusing element couples all the collimated beams to focused beams which pass through the window to intersect within a target region of the sample as confocal beams.

Abstract: This invention provides an angled-dual-axis confocal scanning microscope comprising a fiber-coupled, angled-dual-axis confocal scanning head and a vertical scanning unit. The angled-dual-axis confocal scanning head is configured such that an illumination beam and an observation beam intersect optimally at an angle &thgr; within an object and the scanning is achieved by pivoting the illumination and observation beams using a single scanning element, thereby producing an arc-line scan. The vertical scanning unit causes the angled-dual-axis confocal scanning head to move towards or away from the object.

Abstract: This invention provides an angled-dual-axis optical coherence scanning microscope comprising a fiber-coupled, high-speed angled-dual-axis confocal scanning head and a vertical scanning unit. The angled-dual-axis confocal scanning head is configured such that an illumination beam and an observation beam intersect optimally at an angle &thgr; within an object and the scanning is achieved by pivoting the illumination and observation beams jointly using a high-speed scanning element. The vertical scanning unit causes the angled-dual-axis confocal scanning head to move towards or away from the object, thereby yielding a vertical cross-section scan of the object, while keeping the optical path lengths of the illumination and observation beams unchanged. By incorporating MEMS scanning mirrors and fiber-optic components, the angled-dual-axis optical coherence scanning microscope of the present invention can be miniaturized to provide a particularly powerful tool for in vivo medical imaging applications.

Abstract: The present invention provides a novel class of integrated angled-dual-axis confocal scanning endoscopes. An integrated angled-dual-axis confocal scanning endoscope according to the present invention advantageously exploits an angled-dual-axis confocal arrangement in a silicon micro-machined and fiber-coupled construction, rendering it enhanced resolution, faster scanning, higher sensitivity, highly integrated and scalable structure. An integrated angled-dual-axis confocal scanning endoscope thus constructed can be readily miniaturized for many applications, such as in vivo imaging of biological specimens. One or two illumination beams may be employed in an angled-dual-axis confocal scanning endoscope of the present invention, thereby providing an assortment of reflectance and fluorescence images. An angled-dual-axis confocal scanning endoscope of the present invention is further capable of providing various line and cross-sectional-surface scans with fast speed and high precision.

Abstract: This invention provides an angled-dual-illumination-axis confocal scanning microscope comprising a fiber-coupled, angled-dual-illumination-axis confocal scanning head and a vertical scanning unit. The angled-dual-illumination-axis confocal scanning head is configured such that two illumination beams intersect optimally at an angle &thgr; within an object and the scanning is achieved by pivoting the illumination beams and their corresponding observation beams using a single scanning element, thereby producing an arc-line scan. The vertical scanning unit causes the angled-dual-illumination-axis confocal scanning head to move towards or away from the object, thereby yielding a vertical cross-section scan of the object. The angled-dual-illumination-axis confocal scanning microscope have advantages of enhanced resolution, faster scanning, higher sensitivity and larger dynamic range of detection, a larger field of view and a longer working distance, and a compact and integrated construction.

Abstract: This invention provides an angled-dual-axis confocal scanning microscope comprising a fiber-coupled, angled-dual-axis confocal head and a vertical scanning unit. The angled-dual-axis confocal head is configured such that an illumination beam and an observation beam intersect optimally at an angle &thgr; within an object. The vertical scanning unit causes the angled-dual-axis confocal head to move towards or away from the object, thereby yielding a vertical scan that deepens into the object, while keeping the optical path lengths of the illumination and observation beams unchanged so to ensure the optimal intersection of the illumination and observation beams in the course of vertical scanning. The angled-dual-axis confocal scanning microscope may further comprises a transverse stage, causing the object to move relative to the angled-dual-axis confocal head along transverse directions perpendicular to the vertical direction, thereby producing a transverse scan.

Abstract: An apparatus and method for performing optical coherence domain reflectometry. The apparatus preferably includes a single output light source to illuminate a sample with a probe beam and to provide a reference beam. The reference beam is routed into a long arm of an interferometer by a polarizing beamsplitter. A reflected beam is collected from the sample. A 90° double pass polarization rotation element located between the light source and the sample renders the polarizations of the probe beam and reflected beam orthogonal. The polarizing beamsplitter routes the reflected beam into a short arm of the interferometer. The interferometer combines the reference beam and the reflected beam such that coherent interference occurs between the beams. The apparatus ensures that all of the reflected beam contributes to the interference, resulting in a high signal to noise ratio.

Abstract: An apparatus and method for performing optical coherence domain reflectometry. The apparatus preferably includes a single output light source to illuminate a sample with a probe beam and to provide a reference beam. The reference beam is routed into a long arm of an interferometer by a polarizing beamsplitter. A reflected beam is collected from the sample. A 90° double pass polarization rotation element located between the light source and the sample renders the polarizations of the probe beam and reflected beam orthogonal. The polarizing beamsplitter routes the reflected beam into a short arm of the interferometer. The interferometer combines the reference beam and the reflected beam such that coherent interference occurs between the beams. The apparatus ensures that all of the reflected beam contributes to the interference, resulting in a high signal to noise ratio.

Abstract: An apparatus and method for performing optical coherence domain reflectometry. The apparatus preferably includes a single output light source to illuminate a sample with a probe beam and to provide a reference beam. The reference beam is routed into a long arm of an interferometer by a polarizing beamsplitter. A reflected beam is collected from the sample. A 90° double pass polarization rotation element located between the light source and the sample renders the polarizations of the probe beam and reflected beam orthogonal. The polarizing beamsplitter routes the reflected beam into a short arm of the interferometer. The interferometer combines the reference beam and the reflected beam such that coherent interference occurs between the beams. The apparatus ensures that all of the reflected beam contributes to the interference, resulting in a high signal to noise ratio.

Abstract: A confocal optical scanning system using a flexible optical emissive fiber or fiber laser and having a lasing cavity defined within the fiber. The system in-couples a signal beam produced when a probe beam generated by the fiber laser is reflected from a scanned object back into the lasing cavity. The perturbation created in the cavity by the in-coupling of the signal beam is detected by a transducer. Specifically, the perturbation may be the signal beam itself, an oscillation mode of the cavity induced by the in-coupled signal beam or a combination of the signal beam and the probe beam. In a preferred embodiment of the invention the system also has a polarizing assembly for altering a signal polarization of the signal beam and rotate it to either a resonant polarization supported by the cavity or a non-resonant polarization not supported by the cavity.