In order to realise the clinical potential of Brillouin scattering-based techniques, it is critical to develop an endoscopic probe for measuring elasticity in future in-vivo environments. We have developed a phonon probe which actively injects high amplitude GHz strain pulses into specimens and have demonstrated proof of concept this technique can be used for high resolution 3D imaging. In this talk we show that this new technology is highly applicable to the 3D elasticity imaging of biological tissue from the single-cell scale to multi-cellular organisms and provides a future pathway for the clinical application of in-vivo Brillouin spectroscopy of tissue.
Cancer remains one of the most important contributors to premature mortality at the global level. The elastic properties of cells and tissue have been shown to correlate with normal, dysplastic, and cancerous states. In this work, we rely on time-resolved Brillouin scattering to characterise cancerous and normal cells with contrast provided by their elastic properties. In doing so, we achieved proof of concept that artificial intelligence can be used to differentiate between cancerous and normal cell lines with a low number of highly localised measurements. A differentiation accuracy of 93%, was obtained probing in a volume of a few microns corresponding to a single phonon measurement. Our findings suggest the possibility of potential applications for diagnostics.
Hair-thin optical fiber endoscopes have opened new paradigms for advanced imaging applications, such as optical coherence tomography, which a large depth-of-field is desirable to trade off lateral and axial resolutions. This requirement can be achieved using needle-like Bessel beams, generated by micro-lenses bonded onto fiber tips. In this paper, we compare Fresnel zone plate and axicon mask on fiber tips shaping light into Gaussian foci and Bessel beams, and demonstrate that the axicon-fiber device is capable of imaging a resolution target with large depth-of-field. We also show that our fabrication method is capable of fabricating fiber-imaging devices with multi-layer lens stacks.
This abstract describes a potential method to improve the lateral resolution of Phonon microscopy, a novel noninvasive elasticity imaging microscopy for 3D cell imaging by measuring the time-resolved Brillouin scattering signal. While this technique provides sub-optical axial resolution, the lateral resolution is limited by the optical system that generates the coherent phonon fields. To overcome this limitation, the authors suggest using novel optoacoustic lenses working in GHz frequencies to focus the laser generated coherent phonon fields and thus obtain true acoustic resolution in both axial and lateral dimensions. These lenses can be fabricated at the nanoscale and can also be compatible with ultrasonic endoscopic imaging systems in further applications.
KEYWORDS: Tissues, Tissue optics, Stereoscopy, Scattering, Phonons, Organisms, Optical fibers, New and emerging technologies, Light scattering, In vivo imaging
In order to realise the clinical potential of Brillouin scattering-based techniques, it is critical to develop an endoscopic probe for measuring elasticity in future in-vivo environments. We have developed a phonon probe which actively injects high amplitude GHz strain pulses into specimens and have demonstrated proof of concept this technique can be used for high resolution 3D imaging. In this talk we show that this new technology is highly applicable to the 3D elasticity imaging of biological tissue from the single-cell scale to multi-cellular organisms and provides a future pathway for the clinical application of in-vivo Brillouin spectroscopy of tissue.
In applications such as optical coherence tomography, there is a need both to achieve large depth of field by light shaping and to maintain ultracompact form factors. Flat metasurfaces on optical fibers can achieve such requirements, with designs such as encapsulated diffractive axicon masks. They have the advantages of simple fabrication and transfer, scalability to multi-layer structures and ability to wavelength and/or polarization control. We show a method to shape light from optical fibers via diffractive metallic metalenses bonded onto fiber facets. We discuss a novel process for fabrication and, as proof-of-principle, demonstrate Fresnel zone plates and diffractive axicons on optical fiber facets.
In this paper we present a method to transfer ultra-thin polymer-encapsulated metallic metasurfaces onto optical fibers to enable ultra-thin imaging devices. The metasurface is first produced by conventional e-beam lithography on a silicon substrate and encapsulated by a resist layer. After patterning the resist layer to the target shape, the encapsulated metasurfaces are peeled off from the substrate and then glued onto the tip of a single- or multi-mode optical fiber. As a proof-of-concept we demonstrate a nanowire grating polarizer on the tip of an optical fibre. This method will allow the design and fabrication of multi-layered metasurface endoscopic devices for imaging and sensing.
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