Abstract:
A refractively scanned interferometer, of the type in which a wedge-shaped prism is moved across one interferometer arm for scanning purposes, in which a similarly shaped fixed prism in the other arm provides optical compensation to avoid aberration problems. The beamsplitter surface is on the fixed wedge-shaped prism, and the two wedge-shaped prisms constitute the only refractive elements in the interferometer arms.
Abstract:
An interferometer, preferably of the Michelson type, is disclosed, in which the reflectors associated with the interferometer arms are stationary, and scanning is accomplished by displacement of a single wedge-shaped refractive element in one of the arms. The reflectors are preferably retro-reflectors rather than flat mirrors in order to minimize the effects of chromatic dispersion. A Moire scale may be used to measure the position of the wedge-shaped refractive element.
Abstract:
An interferometer employing a 4f optical imaging system, through which both reference and sample beams are propagated, between diffraction gratings configured as input and output beam-splitting / beam-combining components. A Fourier-transform spectrometer utilizing the same and a microscope as an input optical sub-system. The interferometer includes a variable-phase-delay optical element in a Fourier plane of the imaging spectrometer defined between lens elements of the 4f optical system. In a special case, an additional 4f optical imaging system is used at the output of the interferometer, through which interferograms are registered at the detector. Light output collected by the detector has the same optical path difference between reference and sample beams at any point across field-of-view. A method for performing imaging spectrometry and forming images of an object under the microscope.
Abstract:
The present invention relates to an imaging apparatus and comprises input and output polarisers (20,28), a first polarising beam splitter (22) and at least one additional polarising beam splitter (24), a light sensitive detector (30) and focussing means (26) arranged on an axis. The input polariser (20) resolves incident light into a single linear polarisation state. The first polarising beam splitter (22) receives light from the input polarises (20), and resolves it into equal magnitude orthogonally polarised rays which are mutually spaced and have a path difference therebetween. The or each additional polarising beam splitter (24) is arranged to receive light from the first polarising beam splitter (22). The transmission axis of the output polariser (28) is parallel to or perpendicular to the transmission axis of the input polarises (20) to resolve the orthogonally polarised light rays having past through the or each additional polarising beam splitter (24) into the same or perpendicular polarisation state as light resolved by the, first polariser (20). The first polarising beam splitter (22), the or each additional polarising beam splitter (24) and the focussing means (26) are mutually spaced such that said mutually spaced rays are brought to coincidence whereby interference fringes are produced, the detector (30) being arranged to detect the interference fringes. One beam splitter (24) is mounted for movement perpendicular to said axis, whereas the other beam splitter(s) (22) is/are rigidly mounted against movement.
Abstract:
Fourier Transform Spectroscopy is performed using a birefringent device to vary path difference systematically for all regions of an image simultaneously, so that a separate interferogram is collected for each image region by combining intensity values in multiple images. The optics may allow a theoretical efficiency of 100 % in light throughput.
Abstract:
An interference spectrometer in which a wedge-shaped prism (32) is moved across one arm (22) of an interferometer for variation of the path difference, and where the beam splitter substrate (36) and prism (32) are optically compensated for by elements substantially identical to the substrate and prism (38, 40) in the other arm of the interferometer. In a first embodiment two refractive elements are in each arm of the interferometer (40, 36, 38, 32). In the preferred embodiment, only one prism is used in each arm, (46, 44) with the beam splitter surface (12) being located on a fixed prism (46), in one arm, adjacent a movable prism (44) in the other arm.
Abstract:
Systems and methods according to exemplary embodiments of the present disclosure can be provided that can efficiently detect the amplitude and phase of a spectral modulation. Such exemplary scheme can be combined with self-interference fluorescence to facilitate a highly sensitive depth localization of self-interfering radiation generated within a sample. The exemplary system and method can facilitate a scan-free depth sensitivity within the focal depth range for microscopy, endoscopy and nanoscopy.
Abstract:
Described herein is a hyperspectral imaging system (500) in which a polarising beam splitter (510), a Wollaston prism (520), an optical system (530), and a plane mirror (540) are arranged on an optical axis (550) of the imaging system (500). An imaging detector (560) is provided on which radiation is focussed by an imaging lens (570). The Wollaston prism (520) is imaged on itself by the optical system (530) and the plane mirror (540) so that translation of the Wollaston prism (520) in a direction parallel to a virtual split plane of the prism effectively provides an optical path length difference that is the same for all points in the object field.
Abstract:
A Fourier-domain optical coherence tomography (OCT) imager is presented. An OCT imager according to the present invention can have an auto-alignment process. The auto-alignment process automatically adjusts at least one optical component of a spectrometer of the imager so that the spectrometer is aligned during an imaging session. In addition to the auto-alignment process, OCT spectra are normalized for background spectra and for noise characteristics in order to provide a more accurate and clear OCT image.