Rapid fabrication of micro-nanometric tapered fiber lens and characterization by a novel scanning optical microscope with submicron resolution.
TL;DR: The ability to manufacture a reference tapered fiber lens with high symmetry at sub-wavelength scale with a wide range of geometry control is demonstrated, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius on the endface of a single mode fiber.
Abstract: In numerous applications of optical scanning microscopy, a reference tapered fiber lens with high symmetry at sub-wavelength scale remains a challenge. Here, we demonstrate the ability to manufacture it with a wide range of geometry control, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius from several tens of nanometers to several microns on the endface of a single mode fiber. On this basis, a scanning optical microscope has been developed, which allows for fast characterization of various sub-wavelength tapered fiber lenses. Focal position and depth of microlenses with different geometries have been determined to be ranged from several hundreds of nanometers to several microns. FDTD calculations are consistent with experimental results.
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TL;DR: Infrared imaging of the structures reveals a tight focusing for both structures with a maximum local intensity increase by a factor of 2.5 for a concentrator volume of 1.5 λ3, slightly limited by the residual absorption of the selected polymer.
Abstract: We report on the realization of functional infrared light concentrators based on a thick layer of air-polymer metamaterial with controlled pore size gradients. The design features an optimum gradient index profile leading to light focusing in the Fresnel zone of the structures for two selected operating wavelength domains near 5.6 and 10.4 μm. The metamaterial which consists in a thick polymer containing air holes with diameters ranging from λ/20 to λ/8 is made using a 3D lithography technique based on the two-photon polymerization of a homemade photopolymer. Infrared imaging of the structures reveals a tight focusing for both structures with a maximum local intensity increase by a factor of 2.5 for a concentrator volume of 1.5 λ3, slightly limited by the residual absorption of the selected polymer. Such porous and flat metamaterial structures offer interesting perspectives to increase infrared detector performance at the pixel level for imaging or sensing applications.
30 citations
29 citations
TL;DR: In this article, a simple process of fabrication of micrometer-sized polymer elements (microtips) at the extremities of different type optical fibers, including: standard single mode (SMF-28E+, SM-450), photonic crystal (LMA-10), and polymer (GIPOF-62) ones, is reported.
Abstract: In this paper, we report on a simple process of fabrication of micrometer-sized polymer elements (microtips) at the extremities of different type optical fibers, including: standard single mode (SMF-28E+, SM-450), photonic crystal (LMA-10), and polymer (GIPOF-62) ones. The method of microtips manufacturing is based on the phenomenon of photopolymerization which is successfully used for the first time, to the best of our knowledge, to manufacture microtips at photonic crystal and polymer fibers. We discuss the influence of the initial process parameters on the final microtip characteristics (i.e., length, diameter, and profile). The potential applications of such polymer microtips are near-field scanning optical microscopy, coupling light sources with fibers, and sensing.
21 citations
Cites background or methods from "Rapid fabrication of micro-nanometr..."
...THE practical method of integration of microlenses on optical fibers (MOF) has proved to be powerful in many applications including an efficient coupling between a laser diode and a single-mode fiber (SMF) [1], sub-wavelength optical source for scanning near-field optical microscopy (SNOM) [2]–[5], fiber-integrated optics’ coupling [2], [6], fiber optical tweezers [7], sensing element in Fabry–Perot refractometer [8] or chemical sensor [9]....
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...Moreover, such replacement can influence on a smaller curvature radius of microtips as it is described in [5]....
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TL;DR: In this article, the feasibility of self-positioning nanoemitters onto optical waveguides by visible-light nanoscale photopolymerization was demonstrated, and a light-sensitive material containing nano-emitters was presented.
Abstract: In this article, we demonstrate the feasibility of self-positioning nanoemitters onto optical waveguides by visible-light nanoscale photopolymerization. A light-sensitive material containing nanoem...
21 citations
TL;DR: In this paper, a technique for producing fibers optics micro-collimators composed of polydimethylsiloxane PDMS microlenses of different radii of curvature is presented.
21 citations
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TL;DR: The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
Abstract: Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biological applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biology. Recent examples of their experimental use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-infrared emission during surgery. The new generations of qdots have farreaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
7,499 citations
TL;DR: A brief overview of the main approaches to live cell imaging is given, with some mention of their pros and cons.
Abstract: Since the earliest examination of cellular structures, biologists have been fascinated by observing cells using light microscopy. The advent of fluorescent labeling technologies plus the plethora of sophisticated light microscope techniques now available make studying dynamic processes in living cells almost commonplace. For anyone new to this area, however, it can be daunting to decide which techniques or equipment to try. Here, we aim to give a brief overview of the main approaches to live cell imaging, with some mention of their pros and cons.
1,143 citations
TL;DR: The authors' tip-enhanced CARS microscope visualized the DNA network structure at a specific vibrational frequency corresponding to the ring-breathing mode of diazole of adenine molecules, resulting in a spatial resolution far beyond the diffraction limit of light.
Abstract: An electric field enhanced by a metallic nanoprobe has locally induced coherent anti-Stokes Raman scattering (CARS) of adenine molecules in a nanometric DNA network structure. Owing to the third-order nonlinearity, the excitation of the CARS polarization is extremely confined to the end of the tip apex, resulting in a spatial resolution far beyond the diffraction limit of light. Our tip-enhanced CARS microscope visualized the DNA network structure at a specific vibrational frequency ($\ensuremath{\sim}1337\text{ }\text{ }\mathrm{c}{\mathrm{m}}^{\mathrm{\ensuremath{-}}\mathrm{1}}$) corresponding to the ring-breathing mode of diazole of adenine molecules.
395 citations
TL;DR: High-resolution microlenses are described and illustrated for two-photon imaging of dendritic spines on hippocampal neurons and dual-color nonlinear optical imaging of neuromuscular junctions in live mice.
Abstract: Micro-optics are increasingly used for minimally invasive in vivo imaging, in miniaturized microscopes and in lab-on-a-chip devices. Owing to optical aberrations and lower numerical apertures, a main class of microlens, gradient refractive index lenses, has not achieved resolution comparable to conventional microscopy. Here we describe high-resolution microlenses, and illustrate two-photon imaging of dendritic spines on hippocampal neurons and dual-color nonlinear optical imaging of neuromuscular junctions in live mice.
259 citations
TL;DR: A bidirectional fiber optic probe for the detection of surface-enhanced Raman scattering (SERS) features an array of gold optical antennas designed to enhance Raman signals, while the other facet of the fiber is used for the input and collection of light.
Abstract: This paper reports a bidirectional fiber optic probe for the detection of surface-enhanced Raman scattering (SERS). One facet of the probe features an array of gold optical antennas designed to enhance Raman signals, while the other facet of the fiber is used for the input and collection of light. Simultaneous detection of benzenethiol and 2-[(E)-2-pyridin-4-ylethenyl]pyridine is demonstrated through a 35 cm long fiber. The array of nanoscale optical antennas was first defined by electron-beam lithography on a silicon wafer. The array was subsequently stripped from the wafer and then transferred to the facet of a fiber. Lithographic definition of the antennas provides a method for producing two-dimensional arrays with well-defined geometry, which allows (i) the optical response of the probe to be tuned and (ii) the density of “hot spots” generating the enhanced Raman signal to be controlled. It is difficult to determine the Raman signal enhancement factor (EF) of most fiber optic Raman sensors featuring h...
256 citations