Abstract:
OCT apparatus includes an interferometer, having an input beam splitter and a 50/50 output splitter. The splitting ratio of the input splitter may be optimized depending on the source power of light source and on the mismatch of the balanced receiver. The input splitter is a plate beam-splitter to minimize the stray reflected light in the interferometer and allow sequential operation of the apparatus in the OCT or in the confocal regime. The switching between the two regimes may be at will, or synchronous with the en-face scanning which results in quasi-simultaneous OCT/confocal imaging or in alternatives frames, confocal and OCT. By using polarization sensitive elements, two channels are provided in each regime, OCT and confocal. The two confocal polarization sensitive channels may allow adjustments of compensators prior to OCT measurements or OCT imaging.
Abstract:
OCT apparatus includes an interferometer, having an input beam splitter and a 50/50 output splitter. The splitting ratio of the input splitter may be optimized depending on the source power of light source and on the mismatch of the balanced receiver. The input splitter is a plate beam-splitter to minimize the stray reflected light in the interferometer and allow sequential operation of the apparatus in the OCT or in the confocal regime. The switching between the two regimes may be at will, or synchronous with the en-face scanning which results in quasi-simultaneous OCT/confocal imaging or in alternatives frames, confocal and OCT. By using polarization sensitive elements, two channels are provided in each regime, OCT and confocal. The two confocal polarization sensitive channels may allow adjustments of compensators prior to OCT measurements or OCT imaging.
Abstract:
A method for axial scanning to be used in transmission in one of the arms of OCT interferometers, with reduced walk-off and loss. Procedures are disclosed of using the scanning delay line in conjunction with the transverse scanners to generate B and C-scan OCT images.
Abstract:
Apparatus for high resolution imaging of a moving object comprises a source of low coherence light, an optical coherence tomography imaging instrument or a dual channel, optical coherence tomography/confocal imaging instrument, a transverse scanner, an interferometer, depth adjustment means, and interface optics. First and an optional second sensing blocks sense the axial and respectively the transverse position of the object. A splitting element is shared so that the interface optics and the sensing blocks have a common axis of light transmitted to and from the object. Timing means establishes a timing, and timing intervals and reference times for images as they are taken. The acceptability of each scanned image is determined according to predetermined criteria. A series of en-face OCT images, or of longitudinal OCT images of the object may be taken at different depths or transverse coordinates, and the stack of collected images is used to build 3D profiles of the object.
Abstract:
OCT apparatus includes an interferometer, having an input beam splitter and a 50/50 output splitter. The splitting ratio of the input splitter may be optimized depending on the source power of light source and on the mismatch of the balanced receiver. The input splitter is a plate beam-splitter to minimize the stray reflected light in the interferometer and allow sequential operation of the apparatus in the OCT or in the confocal regime. The switching between the two regimes may be at will, or synchronous with the en-face scanning which results in quasi-simultaneous OCT/confocal imaging or in alternatives frames, confocal and OCT. By using polarization sensitive elements, two channels are provided in each regime, OCT and confocal. The two confocal polarization sensitive channels may allow adjustments of compensators prior to OCT measurements or OCT imaging.
Abstract:
An optical coherence tomography (OCT) apparatus includes an optical source, an interferometer generating an object beam and a reference beam, a transverse scanner for scanning an object with said object beam, and a processor for generating an OCT image from an OCT signal returned by said interferometer. At least the optical source, the interferometer, and the scanner are mounted on a common translation stage displaceable towards and away from said object. A dynamic focus solution is provided when the scanner and a folded object path are placed on the translation stage.
Abstract:
Methods and devices are disclosed for acquiring depth resolved aberration information using principles of low coherence interferometry and perform coherence gated wavefront sensing (CG-WFS). The wavefront aberrations is collected using spectral domain low coherence interferometry (SD-LCI) or time domain low coherence interferometry (TD-LCI) principles. When using SD-LCI, chromatic aberrations can also be evaluated. Methods and devices are disclosed in using a wavefront corrector to compensate for the aberration information provided by CG-WFS, in a combined imaging system, that can use one or more channels from the class of (i) optical coherence tomography (OCT), (ii) scanning laser ophthalmoscopy, (iii) microscopy, such as confocal or phase microscopy, (iv) multiphoton microscopy, such as harmonic generation and multiphoton absorption. For some implementations, simultaneous and dynamic aberration measurements/correction with the imaging process is achieved. The methods and devices disclosed can provide wavefront sensing in the presence of stray reflections from optical interfaces.
Abstract:
A spectral interferometry apparatus and method is provided to supply unambiguous profiles (A—scans free of mirror terms) of the reflectivity versus optical path difference and make difference between the positive and negative optical path difference or provide output in a selected interval of optical path differences. The apparatus comprises object optics that transfer a beam from an optical source to a target object (55) to produce an object beam and reference optics that produce a reference beam. Displacing means (57) are provided to produce a gap (g) between the object beam (41′) and the reference beam (42′). Optical spectrum dispersing means (7) such as a grating or a prism receive the two relatively displaced beams, and disperse their spectral content onto a reading element such as a CCD. The combination of the displacing means and the optical spectrum dispersing means creates an intrinsic optical delay between the wavetrains of the object beam and the reference beam which can be used with the optical path difference in the interferometer to generate a channeled spectrum for the optical path difference in the interferometer on the reading element.
Abstract:
A spectral interferometry apparatus and method is provided to supply unambiguous profiles (A-scans free of mirror terms) of the reflectivity versus optical path difference and make difference between the positive and negative optical path difference or provide output in a selected interval of optical path differences. The apparatus comprises object optics that transfer a beam from an optical source to a target object (55) to produce an object beam and reference optics that produce a reference beam. Displacing means (57) are provided to produce a gap (g) between the object beam (41′) and the reference beam (42′). Optical spectrum dispersing means (7) such as a grating or a prism receive the two relatively displaced beams, and disperse their spectral content onto a reading element such as a CCD. The combination of the displacing means and the optical spectrum dispersing means creates an intrinsic optical delay between the wavetrains of the object beam and the reference beam which can be used with the optical path difference in the interferometer to generate a channelled spectrum for the optical path difference in the interferometer on the reading element
Abstract:
A spectral interferometry apparatus and method are disclosed, that can be used to monitor or measure an unknown length by following a characteristic of an indicating signal. The measurement is performed by adjusting an optical path difference (OPD) in an interferometer part of an interferometer configuration until sound or light or both are obtained with the desired strength and pitch. Embodiments are presented where the unknown length is the eye length. Spectral interrogation of the interferometer optical output is achieved by reading the signal of an analogue photodetector array in a spectrometer or by tuning a swept source and processing the signal of a photodetector. Sound of different pitches are produced either directly in this process, or by using a nonlinear amplifier, or a mixer. For enhanced signal, the array may be driven by a nonlinear clock or the swept source may be driven by a distorted driving signal.