In this paper, an egg-shaped microbubble is proposed and analyzed firstly, which is fabricated by the pressure-assisted arc discharge technique. By tailoring the arc parameters and the position of glass tube during the fabrication process, the thinnest wall of the fabricated microbubble could reach to the level of 873nm. Then, the fiber Fabry–Perot interference technique is used to analyze the deformation of microbubble that under different filling pressures. It is found that the endface of micro-bubble occurs compression when the inner pressure increasing from 4Kpa to 1400KPa. And the pressure sensitivity of such egg-shaped microbubble sample is14.3pm/Kpa. Results of this study could be good reference for developing new pressure sensors, etc.
This paper reports a new silica fiber-tip Fabry-Perot interferometer with thin film and large surface area characteristic for high pressure and vacuum degree detection simultaneously, which is fabricated by etching a flat fiber tip into concave surface firstly, with subsequent arc jointing the concave fiber into a inline Fabry-Perot cavity, then drawing one surface of the F-P cavity into several micrometers scale by arc discharge and finally etching the surface into sub-micrometer scale integrally. As the silica fiber-tip Fabry-Perot interferometer film thickness could be tailored very thinly by HF acid solution, plus the surface area of thin film could be expanded during the chemical etching process, the variation of the bubble cavity length is very sensitive to the inner/outer pressure difference of the fiber-tip Fabry-Perot interferometer. Experimental result shows an high sensitivity of 780nm/MPa is feasible. Such configuration has the advantages of lowcost, ease of fabrication and compact size, which make it a promising candidate for pressure and vacuum measurement.
An improved arc discharge technique was demonstrated to inscribe high-quality LPFGs with a resonant attenuation of - 28 dB and an insertion loss of 0.2 dB by use of a commercial fusion splicer. Such a technique avoids the influence of the mass which is prerequisite for traditional technique. Moreover, no physical deformation was observed on the LPFG surface. Compared with more than 86 grating periods required by traditional arc discharge technique, only 27 grating periods were required to inscribe a compact LPFG by our improved arc discharge technique.
In this paper, the influence of terminal layers on the characters of transmission and power flux in metal-dielectric
multilayer metamaterial (MDMM) has been systematically investigated. Calculation results demonstrate that optical
propagation and optical sigularity in multilayer structure are very sensitive to the thickness and materials of terminal
layers. In addition, we find the termination will greatly affect the propagation performance in form of singularities of
energy flux in MDMM and 100% visibility in superresolution process is always characterized by the appearance of the
singularities (saddle point) in imaging space. Our research will be helpful to actively engineer the energy flux in
nanostructures, especially in real time superresolution imaging, solar cell, nanolithography, etc.
A novel bio-detecting chip configuration based on the fiber surface plasmon enhancement mechanism is proposed and analyzed. Our improvement is proposing to couple the specialized shell-isolated gold nanoparticles into the sensing region of the opened fiber-integrated microfluidic chip, and achieving drastic surface plasmon enhancement by employing the guided optical mode. Simulation shows that the optical intensity distribution near the surface of exposed fiber hole is enhanced drastically, which could be beneficial to the fluorescence or Raman enhancement. Our work could contribute to searching novel microfluidic chip based bio-detecting methods such as for tracing poisonous and harmful substances detection.
Compared with traditional fluorescence-based microstructured fibre sensors using filled structure, the opening-up
microstructured fibres have shown many advantages for real-time sensing. The design and theoretical study about
Cyclops opening-up microstructured fibre is present in this paper. In Cyclops fibre, a large asymmetry hole is placed in fibre cladding. A tri-hole design is adopted for fibre core to enlarge the evanescent field interactions with measured material. This structure is compatible with the traditional stack-draw processing. To make the opening-up structure, chemical etching (with acid) or polishing machining could be used for the asymmetry hole. The opening depth and shape of large asymmetry hole is important for real-time sensing response in Cyclops opening-up fibre. The relationship between marching depth in cladding and fluid concentration distribution at different time in evanescent field near fibre core is analyzed numerically based on incompressible Navier-Stokes equations and finite element method (FEM). The results show that the concentration distribution in evanescent field adjacent to fibre core can reach the true value out of cladding below ten seconds by design cladding structure
appropriately. The field distribution of fundamental mode and some cladding mode of Cyclops fibre without tri-hole core and with different tri-hole are presented in this paper too. Cyclops fibre show good characters in these aspects compared with wagon wheel (WW) opening-up fibre. In order to evaluate the performance of sensing based on Cyclops opening-up fibres we adopted the modal power fraction (PF) within the sensing region and the effective modal area (Aeff) and the fluorescence capture fraction (FCF). The results show the Cyclops opening-up fibre is a competitive candidate for real-time fluorescence sensing.
A designed multilayered metamaterial cavity formed by the metallo-dielectric multilayer structure (MDMS) and a nano
Aluminum layer coated substrate is exploited to achieve the sub-20 nm patterns feature sizes at the wavelength of 248
nm with p-polarization. The filtering and SPP cavity resonance coupling provided by this MDMS cavity regime enable
the SPP interference patterns with high uniformity and intensity output in the photoresist (PR) layer. Furthermore,
compared with the conventional grating metal waveguide structure, this lithography system demonstrates the better
stability of patterns period against the cavity thickness variation. The enhancement and the longitudinal extension of SPP
localized field offered by the proposed cavity scheme will provide a potential way to obtain the lithography patterns with
improved depth, contrast and perpendicularity.
A fast response suspended core fiber optical gas sensor configuration using side-opening hole and micro-holes array
structure on the thin layers is proposed. The side-opening-hole structure enables a fast filling speed of gases into the
opening-up-hole region, while the micro-holes array on the thin layers ensures that gases could further diffuse into
the other holes columns quickly. Meanwhile, its sensitivity could be tripled in contrast to the previous structures.
Simulation results show that a diffusion limited response time of 12 s could be realized and thus move a step further
toward real-time sensing applications.
A fast response tilted fiber Bragg grating fluid refractometer using an exposed-hole microstructured optical fiber is
proposed and analyzed. The theoretical and simulation results show that a sensitivity of 5.40×10-5 r.i.u within a diffusion
limited response time of 6 s could be achieved. This exposed-hole configuration can be used to construct a fluid
refractometer for achieving a fast response, high sensitive distributed detection.