A system and a method for optical sensing of single molecule or molecules in various concentrations are provided. The optical sensor system comprises a first fiber, a second fiber, a light source and a detection device. The first fiber and the second fiber are fused together to form an optical coupler. The first fiber serves as the passageway for the analyte, while the second fiber serves as the waveguide for the light that will interact with the said analyte. One end of the second fiber is connected to the light source (e.g. laser), and the opposite end is connected to the detection device (e.g. spectrometer). The analyte is introduced into the first fiber through one of its ends, and is allowed to flow through inside the hollow core of the said first fiber. When light is delivered through the input end of the second fiber, the evanescent light is formed in the optical coupler and is allowed to interact with the analyte in the first fiber. One scenario in this analyte-light interaction results in, for example, the generation of Raman emission that is used as the probing signal. The spectrum of the Raman emission is analyzed by the detection device to determine the presence of target molecule.

A hybrid Attenuated Total Reflection fiber optic probe device having a radiation source; a detecting system; a core-only solid optical fiber probe tip having an input end and an output end; an input hollow fiber waveguide configured for association with the radiation source at a first end and interconnection with the input end of the core-only solid optical fiber probe tip at a second end; an output hollow fiber waveguide configured for interconnection with the output end of the core-only solid optical fiber probe tip at a first end and association with the detection system at a second end; an inwardly tapered solid fiber input radiation collector element configured at a tapered end for interconnection with the second end of the output hollow fiber waveguide so as to receive radiation from the radiation source; wherein an outside diameter of the core-only solid optical fiber probe tip and an inside diameter of each one of the input hollow fiber waveguide and the output hollow fiber waveguide is such that the interconnection between each one of the input hollow fiber waveguide and the output hollow fiber waveguide and the core-only solid optical fiber probe tip is by means of inserting the input end of the core-only solid optical fiber probe tip into the second end of the input hollow fiber waveguide and inserting the output end of the core-only solid optical fiber probe tip into the first end of the output hollow fiber waveguide, such that the core-only solid optical fiber probe tip is held in the input and output hollow fiber waveguides by means of friction, and wherein an outside diameter of a portion of the inwardly tapered solid fiber input radiation collector element and an inside diameter of the second end of the output hollow fiber waveguide is such that the tapered end of the inwardly tapered solid fiber input radiation collector element is held in the end of the second end of the output hollow fiber waveguide by means of friction.

A hollow-core waveguide structure for guiding an electromagnetic signal, comprising: a core material comprising a predetermined refractive index; and a cladding structure disposed about the core material, wherein the cladding structure has a refractive index that is less than unity; wherein the cladding structure comprises an Epsilon-near-zero (ENZ) metamaterial. The core material comprises air or the like. The cladding structure comprises one of substantially planar sheets disposed about the core material and a substantially tubular structure disposed about the core material. Optionally, the ENZ metamaterial comprises a plurality of nanostructures disposed in a host medium. The plurality of nanostructures comprise a transparent conducting oxide. Alternatively, the cladding structure is manufactured via a self-assembly method.

A light guide apparatus that can redirect light impinging on the apparatus over a wide range of incident angles and can concentrate light without using a tracking system and methods for fabrication. This apparatus uses conditions of total internal reflection and refraction near the critical angle for total internal reflection (near TIR) in order to trap light within the apparatus.

A preform for making a vortex optical fiber comprises a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.

Methods are known for producing an anti-resonant hollow-core fiber which has a hollow core extending along a fiber longitudinal axis and an inner jacket region that surrounds the hollow core, said jacket region comprising multiple anti-resonant elements. The known methods have the steps of: providing a cladding tube that has a cladding tube inner bore and a cladding tube longitudinal axis along which a cladding tube wall extends that is delimited by an interior and an exterior; providing a number of tubular anti-resonant element preforms; arranging the anti-resonant element preforms at target positions of the interior of the cladding tube wall, thereby forming a primary preform which has a hollow core region and an inner jacket region; and elongating the primary preform in order to form the hollow-core fiber or further processing the primary preform in order to form a secondary preform. The aim of the invention is to achieve a high degree of precision and an exact positioning of the anti-resonant elements in a sufficiently stable and reproducible manner on the basis of the aforementioned methods. This is achieved in that while carrying out a process according to step (c), components of the primary preform made of quartz glass and/or parts surrounding the primary preform made of quartz glass are heated and softened together, wherein the quartz glass of at least one of the preform components and/or the quartz glass of at least one of the parts surrounding the preform contains at least one dopant which decreases or increases the viscosity of quartz glass.

Methods are known for producing an anti-resonant hollow-core fiber which has a hollow core extending along a fiber longitudinal axis and an inner jacket region that surrounds the hollow core, said jacket region comprising multiple anti-resonant elements. The known methods have the steps of: providing a cladding tube that has a cladding tube inner bore and a cladding tube longitudinal axis along which a cladding tube wall extends that is delimited by an interior and an exterior; providing a number of tubular anti-resonant element preforms; arranging the anti-resonant element preforms at target positions of the interior of the cladding tube wall, thereby forming a primary preform which has a hollow core region and an inner jacket region; and elongating the primary preform in order to form the hollow-core fiber or further processing the primary preform in order to form a secondary preform. The aim of the invention is to achieve a high degree of precision and an exact positioning of the anti-resonant elements in a sufficiently stable and reproducible manner on the basis of the aforementioned methods. This is achieved in that while carrying out a process according to step (c), components of the primary preform made of quartz glass and/or parts surrounding the primary preform made of quartz glass are heated and softened together, wherein the quartz glass of at least one of the preform components and/or the quartz glass of at least one of the parts surrounding the preform contains at least one dopant which decreases or increases the viscosity of quartz glass.

Laser waveguides, methods and systems for forming a laser waveguide are provided. The waveguide includes an inner cladding layer surrounding a central axis and a glass core surrounding and located outside of the inner cladding layer. The glass core includes a laser-active material. The waveguide includes an outer cladding layer surrounding and located outside of the glass core. The inner cladding, outer cladding and/or core may surround a hollow central channel or bore and may be annular in shape.

The present invention, as disclosed and described herein, in one aspect thereof comprises a preform for making a vortex optical fiber includes a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.

The present invention, as disclosed and described herein, in one aspect thereof comprises a preform for making a vortex optical fiber includes a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.