1. Articles in category: Probes

    1-24 of 583 1 2 3 4 ... 23 24 25 »
    1. Packaged Negative Axicon Optical Fiber Probe and Bessel Beam Interferometry for Refractive Index Measurement of Hazardous Liquid Sample

      Packaged Negative Axicon Optical Fiber Probe and Bessel Beam Interferometry for Refractive Index Measurement of Hazardous Liquid Sample

      In this work, we demonstrate the packaging of an optical fiber negative axicon probe generating Bessel beam and its application in the measurement of refractive index (RI) of hazardous liquids. The negative axicon probe is placed inside cascaded capillary tube capped with a glass coverslip of RI ~1.52 and thickness ~0.15 mm. The packaged probe, connected to a broadband source through an optical circulator, is dipped in different hazardous liquid samples. The reflected light from the air-glass as well as the glass-liquid interface couples to the negative axicon probe and interferes with the reference beam generated at the ...

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    2. Submillimeter diameter rotary-pullback fiber-optic endoscope for narrowband red-green-blue reflectance, optical coherence tomography, and autofluorescence in vivo imaging

      Submillimeter diameter rotary-pullback fiber-optic endoscope for narrowband red-green-blue reflectance, optical coherence tomography, and autofluorescence in vivo imaging

      A fiber-based endoscopic imaging system combining narrowband red-green-blue (RGB) reflectance with optical coherence tomography (OCT) and autofluorescence imaging (AFI) has been developed. The system uses a submillimeter diameter rotary-pullback double-clad fiber imaging catheter for sample illumination and detection. The imaging capabilities of each modality are presented and demonstrated with images of a multicolored card, fingerprints, and tongue mucosa. Broadband imaging, which was done to compare with narrowband sources, revealed better contrast but worse color consistency compared with narrowband RGB reflectance. The measured resolution of the endoscopic system is 25  μm in both the rotary direction and the pullback direction. OCT ...

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    3. Low cost scalable monolithic common path probe design for the application in endoscopic optical coherence tomography

      Low cost scalable monolithic common path probe design for the application in endoscopic optical coherence tomography

      Endoscopic optical coherence tomography is an interference based imaging technique which due to its micron level resolution ability found several applications in medical diagnostics. However, the standard image performance suffers from artefacts caused by dispersion imbalance and polarisation mismatches between reference and sample arm. Such artefacts can be minimised with the use of a special class of probes called common path probes where the reference surface is placed in the vicinity of the sample. Previously reported common path probes suffered from a compromise between sensitivity and resolution. In most cases, proposed probes were not scalable for industrial applications and required ...

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    4. Metasurface-based focus-tunable mirror

      Metasurface-based focus-tunable mirror

      Varifocal mirrors, which have various applications in optical coherent tomography and three-dimensional displays, are traditionally based on the fluid pressure or mechanical pusher to deform the mirror. The limitations of conventional varifocal mirrors are obvious, such as the heavy size of the device and constraints of tunability, due to their mechanical pressure control elements. The reprogrammable metasurface, a new flat photonic device with multifunction in an ultrathin dimension, paves the way towards an ultrathin and lightweight mirror with precise phase profile. Here, an active reconfigurable metasurface is proposed to achieve the manipulation of the wavefront. The meta-atom in the metasurface ...

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    5. Precision Microfabrication of Optical Probes for Intravascular Diagnostics (Thesis)

      Precision Microfabrication of Optical Probes for Intravascular Diagnostics (Thesis)

      This thesis details a collection of design, optimisation, fabrication and characterisation work to form fiber-optic probes and optical phantom devices for intravascular diagnostics in minimally invasive surgery (MIS). Optically generated ultrasound is an emerging technique to create broadband high frequency ultrasound via the photoacoustic effect. In the first segment of this thesis, the development of a novel miniature fiber-optic ultrasound transmitter is detailed. A morphologically controlled coating was formed at the endface of a multimode optical fiber by controlled electrospinning of a carbon-nanotube composite. Efficient optical ultrasound generation was realised, with signal amplitude, bandwidth and device form factor suited to ...

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    6. Comparison of optical coherence tomography angiography and narrow-band imaging using a bimodal endoscope

      Comparison of optical coherence tomography angiography and narrow-band imaging using a bimodal endoscope

      We present coregistered images of tissue vasculature that allow a direct comparison between the performance of narrow-band imaging (NBI) and optical coherence tomography angiography (OCTA). Images were generated with a bimodal endomicroscope having a size of 15  ×  2.4  ×  3.3  mm 3   (   l   ,   w   ,   h   )   that combines two imaging channels. The white light imaging channel was used to perform NBI, the current gold standard for endoscopic visualization of vessels. The second channel allowed the simultaneous acquisition of optical coherence tomography (OCT) and OCTA images, enabling a three-dimensional (3-D) visualization of morphological as well as functional tissue information. In order ...

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    7. Optical probe using multimode optical waveguide and proximal processing

      Optical probe using multimode optical waveguide and proximal processing

      An optical probe includes an optical source that generates an optical beam that propagates from a proximal end to a distal end of an optical fiber that imparts a transformation of a spatial profile of the optical beam. An optical control device imparts a compensating spatial profile on the optical beam that at least partially compensates for the transformation of the spatial profile of the optical beam imparted by the optical fiber in response to a control signal from a signal processor. A distal optical source generates a calibration light that propagates through the one or more optical waveguides from ...

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      Mentions: Eric A. Swanson
    8. Optical Fabrication: Glassblowing technique creates arrays of axicon lenses

      Optical Fabrication: Glassblowing technique creates arrays of axicon lenses

      Axicon lenses , which are conical in shape, are widely used to create so-called nondiffracting Bessel beams , which form a long, line-shaped focal region rather than the usual point focus. The line focus is useful for alignment, microfabrication, and other applications due to its insensitivity to axial motion, but cones are much more difficult than spheres to create in glass. Traditional optical techniques, such as grinding and polishing, or other approaches, such as femtosecond-laser ablation followed by polishing with a CO 2 laser, can be used, but are complex and not suited to large-volume production. Researchers at the FEMTO-ST Institute (Besan ...

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    9. Optical Coherence Tomography/Fluorescence Imaging: Fiber assembly enables efficient multimodal endoscopy

      Optical Coherence Tomography/Fluorescence Imaging: Fiber assembly enables efficient multimodal endoscopy

      While optical coherence tomography (OCT) provides structural contrast with a resolution on the order of tens of microns, for some applications this information is, in some contexts, insufficient to provide a definitive diagnostic. To mitigate this limitation, OCT has been used in conjunction with fluorescence imaging or spectroscopy for detection of molecular content in tissues. The combination of OCT and fluorescence has been used for a variety of applications, most notably to study atherosclerotic plaque in cardiology, 1 to visualize the fine vascular network in pulmonology (for which autofluorescence is used), 2 and for cancer imaging. 3

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    10. Micrometer size multi-functional probe for OCT and electro-physiological recording

      Micrometer size multi-functional probe for OCT and electro-physiological recording

      A device and method for guided insertion of microelectrodes into tissue is provided. The device includes a flexible optical fiber for optical coherence tomography imaging, a metal layer coating the optical fiber for recording electrical signals and an outer insulation layer coating the metal layer along the optical fiber length. The method includes inserting an optical fiber coated with a metal layer and further coated with an insulation layer into a tissue, collecting intraoperative image data through the optical fiber by optical coherence tomography, receiving the image data on a computer and displaying the image on a monitor, using the ...

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    11. Polarization-sensitive optical coherence tomography with a conical beam scan for the investigation of birefringence and collagen alignment in the human cervix

      Polarization-sensitive optical coherence tomography with a conical beam scan for the investigation of birefringence and collagen alignment in the human cervix

      By measuring the phase retardance of a cervical extracellular matrix, our in-house polarization-sensitive optical coherence tomography (PS-OCT) was shown to be capable of (1) mapping the distribution of collagen fibers in the non-gravid cervix, (2) accurately determining birefringence, and (3) measuring the distinctive depolarization of the cervical tissue. A conical beam scan strategy was also employed to explore the 3D orientation of the collagen fibers in the cervix by interrogating the samples with an incident light at 45° and successive azimuthal rotations of 0-360°. Our results confirmed previous observations by X-ray diffraction, suggesting that in the non-gravid human cervix collagen ...

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    12. Physical Sciences Inc Receives NIH Grant for Multimodal Optical Probe for Skin Cancer Detection and Therapy Guidance

      Physical Sciences Inc Receives NIH Grant for Multimodal Optical Probe for Skin Cancer Detection and Therapy Guidance

      Physical Sciences Inc Receives a 2019 NIH Grant for $300,000 for Multimodal Optical Probe for Skin Cancer Detection and Therapy Guidance. The principal investigator is Nicusor Iftimia. The program began in 2019 and ends in 2020. Below is a summary of the proposed work. The primary goal of this research project is to develop and translate to clinical use a novel optical imaging technology based on combined Optical Coherence Tomography (OCT) and Confocal Microscopy (CM) for non- invasive real-time diagnosis of non-melanoma skin cancers (NMSCs), tumor subtyping and margin mapping that will assist physician-patient decision in treatment planning (biopsy ...

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    13. Motorized capsule for shadow-free OCT imaging and synchronous beam control

      Motorized capsule for shadow-free OCT imaging and synchronous beam control

      We demonstrate a tethered motorized capsule for unobstructed optical coherence tomography (OCT) imaging of the esophagus. By using a distal reflector design, we avoided the common shadow artifact induced by the motor wires. A synchronous driving technique features three types of beam-scanning modes of the capsule, i.e., circumferential beam scanning, localized beam scanning, and accurate beam positioning. We characterized these three modes and carried out ex vivo imaging experiments using the capsule. The results show that the capsule can potentially be a useful tool for diagnostic OCT imaging and OCT-guided biopsy and therapy of the esophagus.

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    14. Using Optical Coherence Tomography to Make Needle Biopsies Safer

      Using Optical Coherence Tomography to Make Needle Biopsies Safer

      Stereotactic needle biopsy continues to be widely employed in the diagnosis of intracranial lesions. Despite an overall low complication rate, hemorrhage remains one the most common and potentially serious risks of the procedure. Previous series have reported a symptomatic hemorrhage rate of 3% to 6%, with a minority requiring craniotomy and hemorrhage evacuation. 1-4 Though certain factors inherent to the lesion or the patient have been known to increase hemorrhage risk, 2 , 3 up until this point there has been little that surgeons can do intraoperatively to avoid hemorrhage after a trajectory has been selected. A new report in Science ...

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    15. Ultralow-voltage electrothermal MEMS based fiber-optic scanning probe for forward-viewing endoscopic OCT

      Ultralow-voltage electrothermal MEMS based fiber-optic scanning probe for forward-viewing endoscopic OCT

      We report an ultralow-voltage, electrothermal (ET) micro-electro-mechanical system (MEMS) based probe for forward-viewing endoscopic optical coherence tomography (OCT) imaging. The fully assembled probe has a diameter of 5.5 mm and a length of 55 mm, including the imaging optics and a 40 mm long fiber-optic cantilever attached on a micro-platform of the bimorph ET MEMS actuator. The ET MEMS actuator provides a sufficient mechanical actuation force as well as a large vertical displacement, achieving up to a 3 mm optical scanning range with only a 3

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    16. Long-range common-path spectral domain optical coherence tomography

      Long-range common-path spectral domain optical coherence tomography

      Fiber-based common-path spectral domain optical coherence tomography (SD-OCT) is compact and polarization insensitive, which is usually used in endoscopic biomedical imaging. In this study, we investigate a method to extend the working distance of a common-path SD-OCT system. Common-path OCT light, which consisting of sample and reference light signal, is directed into a free space optical interferometer. The OCT light is split spatially into two beam segments by a wavefront-splitting mirror, and the two parallel beams interfere noncollinearly in the interferometer. Distance between the end of the probing fiber, which serves as the reference plane of our OCT system, and ...

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    17. Development of a clinical prototype of a miniature hand-held optical coherence tomography probe for prematurity and pediatric ophthalmic imaging

      Development of a clinical prototype of a miniature hand-held optical coherence tomography probe for prematurity and pediatric ophthalmic imaging

      We report a novel design and operation of a highly integrated miniature handheld OCT probe, with high-speed angiography function that can be used in clinical settings for young children and infants, providing rapid, non-invasive structural and angiographic imaging of the retina and choroid. The imaging system is operated at 200 kHz, with 3D OCT and OCTA scan time of 0.8 and 3.2 seconds, respectively, and the scanning angle on the pupil is ± 36°, covering the full perifoveal region. Operator assisting features of the direct-view iris camera and on-probe display are integrated into the hand-held probe, and the fixation ...

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    18. This compact and cheap lidar could steer small autonomous vehicles

      This compact and cheap lidar could steer small autonomous vehicles

      Researchers in Sweden have developed cheaper, lighter and more efficient lidar technology that could pave the way for smaller autonomous craft such as drones and robots, and help enable better profitability in the vehicle industry. For autonomous vehicles, lidar is an essential technology to recognize and detect surrounding objects. A team at KTH Royal Institute of Technology has taken aim at the key component of lidar, optical beam-stearing, and developed a device that is significantly cheaper to manufacture, lighter and more resource-efficient than previous variations of the technology. Carlos Errando-Herranz, a postdoc at KTH's 's Division of Micro and ...

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    19. Balloon catheter-based radiofrequency ablation monitoring in porcine esophagus using optical coherence tomography

      Balloon catheter-based radiofrequency ablation monitoring in porcine esophagus using optical coherence tomography

      We present a microscopic image guidance platform for radiofrequency ablation (RFA) using a clinical balloon-catheter-based optical coherence tomography (OCT) system, currently used in the surveillance of Barrett’s esophagus patients. Our integrated thermal therapy delivery and monitoring platform consists of a flexible, customized bipolar RFA electrode array designed for use with a clinical balloon OCT catheter and a processing algorithm to accurately map the thermal coagulation process. Non-uniform rotation distortion was corrected using a feature tracking-based technique, which enables robust, frame-to-frame analysis of the temporal fluctuation of the complex OCT signal. With proper noise calibration, precise delineation of the thermal ...

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    20. A FBG-OCT Catheter to reconstruct vascular shape in intravascular optical coherence tomography

      A FBG-OCT Catheter to reconstruct vascular shape in intravascular optical coherence tomography

      We propose a novel Fiber Bragg Grating (FBG)-Optical Coherence Tomography (OCT) catheter to reconstruct vascular shape by intravascular OCT imaging of the actual curvature as well as the bending direction of the vascular in real-time. Compared with the traditional OCT catheter, the FBG-OCT catheter uses the FBG encapsulated with half-sectioned stainless-steel tube as a flexural sensitive component. With the 360-degree rotation of the catheter, the encapsulated FBG will produce maximum tension and maximum compression at the bend of the blood vessel, and then get the solution of the curvature and direction of the bending catheter as well as the ...

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      Mentions: Tiegen Liu
    21. Method and system for characterising biological tissue

      Method and system for characterising biological tissue

      The present disclosure provides a method for characterizing a region of interest within or between biological tissue. The method comprises inserting at least a portion of a probe into the region of interest and directing electromagnetic radiation to the region of interest and receiving electromagnetic radiation from the region of interest using the probe in a direction that is transversal to a length of the probe. Further, the method comprises directing a fluid to the region of interest through a portion of the probe and analyzing received electromagnetic radiation.

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    22. Optical probes with reflecting components for astigmatism correction

      Optical probes with reflecting components for astigmatism correction

      Some devices comprise a first light-guiding component, a second light-guiding component, a lens, an optical-correction component that has a reflecting surface that faces the lens, and a sheath, which causes astigmatism. The reflecting surface has an optical power on a first axis of two orthogonal axes, the optical power on the first axis compensates for the astigmatism, and the reflecting surface has a negligible optical power on a second axis of the two orthogonal axes. Also, the reflecting surface is configured to reflect light from the lens and redirect the reflected light through the sheath.

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    23. Frustrated total internal reflection fingerprint detector

      Frustrated total internal reflection fingerprint detector

      The device provides an optical coherence tomography system; a first bank of light emitting diodes emitting light centered about a first wavelength; a second bank of light emitting diodes, emitting light centered about a second wavelength; a prism, said prism including a first surface transmissive of the wavelength of the probe beam of the optical coherence tomography system, and a second surface which is also transmissive of the wavelength of the probe beam, and where the second is surface coated from a first edge to a midpoint so to be reflective of light at the first wavelength and transmissive of ...

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    24. Finger-mounted quantitative micro-elastography

      Finger-mounted quantitative micro-elastography

      We present a finger-mounted quantitative micro-elastography (QME) probe, capable of measuring the elasticity of biological tissue in a format that avails of the dexterity of the human finger. Finger-mounted QME represents the first demonstration of a wearable elastography probe. The approach realizes optical coherence tomography-based elastography by focusing the optical beam into the sample via a single-mode fiber that is fused to a length of graded-index fiber. The fiber is rigidly affixed to a 3D-printed thimble that is mounted on the finger. Analogous to manual palpation, the probe compresses the tissue through the force exerted by the finger. The resulting ...

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    1-24 of 583 1 2 3 4 ... 23 24 25 »
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