High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.

High index-contrast fiber waveguides and applications

Acquisition of high-resolution images from within internal organs using endoscopic optical imaging has numerous clinical applications. However, difficulties associated with optical aberrations and the trade-off between transverse resolution and depth-of-focus significantly limit the scope of applications. Here, we integrate a metalens, with the ability to modify the phase of incident light at sub-wavelength level, into the design of an endoscopic optical coherence tomography catheter (termed nano-optic endoscope) to achieve near diffraction-limited imaging through negating non-chromatic aberrations. Remarkably, the tailored chromatic dispersion of the metalens in the context of spectral interferometry is utilized to maintain high-resolution imaging beyond the input field Rayleigh range, easing the trade-off between transverse resolution and depth-of-focus. We demonstrate endoscopic imaging both in resected human lung specimens and in sheep airways in vivo. The combination of the superior resolution and higher imaging depth-of-focus of the nano-optic endoscope will likely increase the clinical utility of endoscopic optical imaging.

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Nano-optic endoscope for high-resolution optical coherence tomography in vivo

Apparatus, systems and methods for improving strength of a thin glass cover for an electronic device are disclosed. In one embodiment, the glass member can have improved strength by forming its edges with a predetermined geometry and/or by chemically strengthening the edges. Advantageously, the glass member can be not only thin but also adequately strong to limit susceptibility to damage. In one embodiment, the glass member can pertain to a glass cover for a housing for an electronic device. The glass cover can be provided over or integrated with a display, such as a Liquid Crystal Display (LCD) display.

Techniques for Strengthening Glass Covers for Portable Electronic Devices

We report a study of the determination of polymer cross-linking, namely the degree of conversion and refractive index of the microstructures created by two-photon polymerization (TPP). The influence of TPP processing parameters such as laser intensity and scanning velocity is investigated. The degree of conversion is analyzed via Raman microspectroscopy and the refractive index is measured with the interferometric technique employing a Michelson interferometer. Moreover, the relationship between these two properties is revealed and details are discussed. The largest refractive index change that we have obtained is of the order of 10−2. Finally, we propose and demonstrate experimentally the realization of the gradient-index (GRIN) structure, resulting from a laser-induced local refractive index modification due to monomer cross-linking, i.e. degree of conversion. This work implies that the TPP technique is a valuable tool for the fabrication of GRIN microoptics for (in)homogeneous molding of light flow at the micrometer scale.

Tuning the refractive index in 3D direct laser writing lithography: towards GRIN microoptics

Gradient-index rod lenses with a parabolic-index profile have been fabricated by a double Na–Ag ion-exchange process, and their optical characteristics have been evaluated. The numerical aperture and minimum focused spot diameter of the 2-mm diam rod lens were 0.58 and 2.5 μm for λ = 0.63 μm, respectively. Because of the high diffusing rate for Ag ions, this technique offers the possibility of making large-sized (larger than 10 mm-diam) rod lenses for photographic uses.

Gradient-index rod lens made by a double ion-exchange process

The refractive index distribution in refractive index distribution lenses may be adjusted to better approach an ideal by heating the refractive index distribution lens. When the refractive index distribution lens was created by diffusion of refractive index changing ions into a body, further heating in an environment in which no additional ions can diffuse into the body causes further migration of ions within the body so that its refractive index distribution approaches an ideal.

Method of adjusting refractive index distribution lenses

The present invention provides a gradient refractive index type anamorphic planar microlens which can be utilized for collimating an elliptical beam radiated from a semiconductor laser, or the like, and a method of producing such a lens. To collimate light rays, in which astigmatism exists, it is necessary to use a lens in which the respective focal distances in the directions perpendicular to an optical axis are different from each other. It includes a semiellipsoidal refractive index distribution region formed in a transparent substrate so as to have a major axis and a minor axis on a surface of the transparent substrate.

Gradient refractive index type anamorphic planar microlens and method of producing the same

Chalcogenide glass fibers having a glass core with two cladding glass layers, the second cladding glass layer having a refractive index lower than that of the core glass and higher than that of the first cladding glass. The core glass does not contain germanium. Glass fiber having this core-cladding structure is mechanically strong and exhibits only small transmission loss of infrared light passing through the fiber.

Chalcogenide glass fiber

A polarizing glass comprising geometrically anisotropic particles dispersed in an oriented manner in at least the surface of a glass base body. The glass base body is denoted by the weight percentages of 50-65 percent SiO2, 15-22 percent B2O3, 0-4 percent Al2O3, 2-8 percent ZrO2, 6 percent <Al2O3+ZrO2<12 percent, 6-16 percent R2O (where R denotes at least one from among Li, Na, and K), 0-3 percent Li2O, 0-9 percent Na2O, 4-16 percent K2O, Li2O+Na2O<K2O, 0-7 percent BaO and/or SrO, and 0-3 percent TiO2. The glass base body comprises per 100 weight percent of essentially the above composition at least 0.15-1.0 percent Ag and at least the chemical equivalent to Ag of Cl and/or Br; and the geometrically anisotropic silver particles are metallic Ag particles. The polarizing glass is employed in optical products such as optical isolators.

Yoshitaka Yoneda

Papers

Gradient-index rod lens made by a double ion-exchange process

Method of adjusting refractive index distribution lenses

Gradient refractive index type anamorphic planar microlens and method of producing the same

Chalcogenide glass fiber

Polarizing glass and preparation method thereof