Molecularly imprinted polymer-coated hybrid optical waveguides for sub-aM fluorescence sensing.

The sensitivity of fluorescent sensors is crucial for their applications. In this study, we propose a molecularly imprinted polymer (MIP)-coated optical fibre-hybrid waveguide-fibre sensing structure for ultrasensitive fluorescence detection. In such a structure, the MIP coated-hybrid waveguide acts as a sensing probe, and the two co-axially connected optical fibres act as a highly efficient probing light launcher and a fluorescence signal collector, respectively.

Molecularly Imprinted Polymer-Coated Optical Waveguide for Attogram Sensing.

Ultrahigh sensitivity and selectivity are the ultimate goals of sensor development. For such purposes, we propose a sensing platform in which an optical fiber-waveguide-fiber (OFWF) structure is integrated with a molecularly imprinted polymer (MIP). The OFWF works as a highly efficient probe light launcher and signal light collector, and the MIP layer acts as a highly selective and sensitive sensing interface.

One-Drop Self-Assembly of Ultra-Fine Second-Order Organic Nonlinear Optical Crystal Nanowires.

In this study, we propose a one-drop self-assembly method, which proved capable of successfully preparing 4-N, N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST) single-crystalline nanowires (NWs). The apparent roughness of the DAST NWs was determined to be less than 100 pm by using a high-resolution atomic force microscope, indicating their ultrafine quality. The DAST NWs also exhibited excellent nonlinear optical properties, including two-photon excited fluorescence and second harmonic generation, which could enable the production of low-cost, low-power-consumption wideband wavelength conversion devices.

Camera sensor platform for high speed video data transmission using a wideband electro-optic polymer modulator.

In this work, 1 GHz video data was collected by a CMOS camera and successfully transmitted by the electro-optic (EO) modulator driven by an external modulation module integrated onto the same chip. For this application, the EO modulator component included a polymer waveguide modulator, which performed a 20 GHz bandwidth, clear eye diagram opening with a Q factor of 10.3 at 32 Gbit/s and a drive voltage of 1.

Ultra-Broadband THz Antireflective Coating with Polymer Composites.

Achieving an ultra-broadband range is an essential development direction in terahertz techniques; however, a method to cover the full terahertz band by using a highly efficient antireflection (AR) coating that could greatly increase the efficiency of terahertz radiation is still lacking. It is known that structures possessing a graded-index profile can offer a broadband AR effect, and such structures have been widely used, especially in the visible range. In this paper, first, we tuned the refractive index of a cyclo-olefin polymer (COP) by using a TiO₂ dopant, and a polymer⁻TiO₂ composite with a refractive index of 3.

Light-induced self-written waveguide fabrication using 1550 nm laser light.

Light-induced self-written (LISW) optical waveguides were fabricated for the first time, to the best of our knowledge, using a photopolymerizable resin system formed by 1550 nm pulse laser light. A two-photon absorption (TPA) chromophore with a TPA cross section of several hundred Goeppert-Mayer (GM) at 1550 nm was used. Furthermore, the optical interconnection between a single-mode fiber and a fiber Bragg grating was demonstrated by the present technique, using one-way irradiation of 1550 nm laser light through the single-mode fiber.

Launch light dependency of step-index multimode fiber connections analyzed by modal power distribution using encircled angular flux.

The propagating modal power distribution (MPD) of step-index multimode fibers (SI-MMFs), which strongly influences the performance of systems and components composed of these fibers, has not often been discussed, because, until recently, there has been no definition to show the MPD. Encircled angular flux (EAF) is a newly developed metric for defining the MPD in step-index multimode waveguides including fibers standardized by the International Electrotechnical Commission. Using the combined analysis of EAF and insertion loss, we studied the launch light dependency of SI-MMF connections.

0.1-20 THz ultra-broadband perfect absorber via a flat multi-layer structure.

An ultra-broadband perfect absorber based on graded-index mechanism is designed and fabricated. The perfect absorber is comprised of a heavily-doped silicon absorption substrate and a flat six-layer antireflective structure. The refractive index of each layer was widely tuned by hollow polystyrene microsphere and TiO nanoparticle dopants, which can offer a gradually changed refractive index profile from 1.

DAST single-nanometer crystal preparation using a substrate-supported rapid evaporation crystallization method.

A substrate-supported rapid evaporation crystallization (SSREC) method was used to develop a highly nonlinear optical material, 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST), which satisfies the Rayleigh scattering requirement for the fabrication of highly transparent composites. DAST nanocrystals have a second harmonic generation active crystal structure and a high signal-to-noise ratio second harmonic generation signal when excited by using a 1064 nm cw laser. The nanocrystals also possess size-dependent UV-vis absorption and fluorescence behavior which is not seen in the bulk state.

Rayleigh scattering study and particle density determination of a high refractive index TiO2 nanohybrid polymer.

We have experimentally carried out a Rayleigh scattering study of a high refractive index TiO(2) nanohybrid polymer. By employing the Rayleigh scattering technique with at least three different wavelengths, we can obtain the Rayleigh ratio of the TiO(2) nanohybrid polymer at each utilized wavelength. These measured Rayleigh ratios are then used to estimate the size of the nanoparticle and determine the number of nanoparticles per unit volume or particle density.

Encircled Flux-based optimized simple launch condition for standardization of multimode polymer optical waveguide evaluations.

Multimode polymer optical waveguide evaluations by using a combination of multimode optical fibers (MMF) and Light Emitting Diode (LED) give very often inconsistent experimental result. It is due to the over-filled properties of the launch light created by this configuration. We propose an optimized simple launch configuration to overcome the problems by using similar configuration.

Refractive index control and Rayleigh scattering properties of transparent TiO2 nanohybrid polymer.

The surface of TiO2 nanoparticles (NPs) was modified by a coupling agent of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane to render them highly compatible with organic monomer mixtures avoiding aggregation. Such TiO2 NPs were then chemically attached with a prepolymer. The refractive index of hybrid TiO2 NPs-polymer was increased dramatically in comparison with that of pure polymer, and it can be controlled by adjusting the content of TiO2 NPs.

Serially grafted polymer optical waveguides fabricated by light-induced self-written waveguide technique.

Serially grafted polymer optical waveguides were fabricated by the light-induced self-written (LISW) waveguide technique for the first time to our knowledge. To realize functional waveguide cores by the LISW technique, transparent materials at the writing wavelength were selected. By inserting thin transparent partitions, a serial-graft structure consisting of passive and active waveguides without any misalignment was realized automatically.