A fiber Mach–Zehnder interferometer (MZI) sensor, novel to our knowledge, based on a single "S"-like taper has been fabricated via applying nonaxial pull in tapering by fusion splicer. The typical feature size of the structure length 660 μm and axial offset 96 μm. This S MZI refractive index (RI) sensitivity 1590 nm/refractive unit RI range 1.409–1.425 strain about −60 pm/microstrain, which is 30 times higher than that normal two-taper-based sensors.

An S-tapered fiber sensor has been realized on the common single-mode by a fusion splicer. The S taper (SFT) can be considered as compact Mach-Zehnder interferometer with total length of hundreds microns. spectral characteristics SFTs different structure parameters including axial offsets and waist diameters have studied. Sensing experiments also carried out to test their response refractive index (RI) strain. SFT an offset 114 μm diameter 54.6 exhibits best combination property. Its RI...

Abstract Organic crystals have great potential for the applications in laser devices. This article presents an effective approach fabrication of distributed feedback single crystal lasers. With interference ablation method, high quality grating structures been fabricated on organic single‐crystalline thin film materials. The relationship between depth, periodicity, and fluence is discussed. optical properties, such as photoluminescence, diffractive properties are studied detail. appropriate...

We demonstrate an ultrasensitive temperature sensor based on isopropanol-sealed optical microfiber taper (OMT) in a capillary. The OMT is highly sensitive to ambient refractive index (RI) with maximum sensitivity of 18989 nm/RI unit the range 1.3955-1.4008. thermo-optic effect isopropanol and thermal expansions sealant sealed liquid turn into -3.88 nm/°C 20°C-50°C. contributions from different mechanisms are also investigated theoretically experimentally.

We have demonstrated an end-of-fiber polydimethylsiloxane (PDMS) cap based fiber Fabry-Pérot interferometer in this letter, which could be used for simultaneous measurement of refractive index (RI) and temperature with extremely low cross sensitivity. The RI sensitivities the are -240.425 dB/RI unit on extinction ratio range 1.3625-1.4150 385.46 pm/°C 25°C-60°C, respectively. Not only does characteristics high sensitivity cost, but also PDMS has a good biocompatibility, so that sensor can as...

We have demonstrated a refractive index (RI) sensor based on an S-tapered fiber probe (STFP) with silver mirror its end facet. The has compact size of about 1 mm, making it proper for sensing in narrow or limited space. reflection spectra the STFPs different structure lengths been analyzed and simulated. Its RI sensitivity range 1.332 ~1.387 reaches 268.8 nm/RI unit, which is 9 times higher than that existing reflective fiber-taper-based sensor. Furthermore, thermal response experimental...

A novel highly sensitive fiber sensor for transverse load and temperature measurement has been fabricated by polydimethylsiloxane (PDMS) packaging an S taper (SFT). The PDMS coating is effective transducer due to its material characteristics, such as low Young's modulus, high Poisson's ratio, large thermooptic coefficient, which can efficiently transfer the lateral force into axial tension on SFT or convert refractive index (RI) change around SFT. Because strain surrounding RI, PDMS-coated...

Compact 5-mm-long 100-μm-period long-period fiber gratings (LPFGs) are fabricated by femtosecond laser direct writing. Nearly symmetrical photomodified grating segments located at the center of a core lead to well-defined transmission spectra. The LPFGs can couple guided mode high-order cladding modes second-order diffraction, resulting in high refractive index (RI) sensitivity 5265 nm/RI units RI range 1.433 ~ 1.443 and low-temperature -15.52 pm/°C from 20°C 500°C. latter property is...

A hybrid acoustic cloaking, composed of binary splitting metasurfaces (BSMs) and near-zero-index metamaterials (NZIMs), is proposed in this paper. The BSMs form cloaking to make the incident waves diffract around obstacle, while NZIMs can straightly transfer input layer control emergent from output propagate along original direction. Due tunneling effect, compensate for extra phase wave diffraction improve efficiency cloaking. As consist Helmholtz cavities cylinders, respectively, simple...

A compact fiber tip modal interferometer (FTMI) based on two-wave interference has been demonstrated. Its fabrication process is very simple, just involving tapering by a fusion splicer. The effective sensing area of the FTMI small length ∼310 μm. spectra tips with different size and profile have analyzed. good mechanical strength high-temperature stability. It can be used for transverse load simultaneously in harsh environment when two attenuation peaks are chosen to monitored.

A microhole array in a common single-mode fiber is fabricated by selective chemical etching of femtosecond-laser-induced Bragg grating (FBG), which has laser-modified region extending from the core to cladding–air boundary due laser self-focusing. The shape and size orderly on surface are controlled via changing conditions FBG fabrication etching. simultaneous sensing for surrounding refractive index temperature demonstrated this through measurement transmission power change resonant...

The goal of creation large-area deep sub-wavelength nanostructures by femtosecond laser irradiation onto various materials is being hindered the limited coherence length. Here, we report solution problem light field tailoring incident beam with a phase mask, which serves generation wavelets. Direct interference between wavelets, here first-order diffracted beams, and wavelet its induced waves such as surface plasmon polariton are responsible for microgratings superimposed nanogratings,...

A point-by-point dip coating method has been proposed and demonstrated for fabricating long-period gratings (LPGs) in microfibers. Using a high precision 3D translation stage, the grating structure is formed by periodically immersing microfiber into miniature polydimethylsiloxane droplet suspended at end-tip of single mode fiber. 10-period LPG with period about 143 μm fabricated 7.6 diameter demonstrates resonant 19 dB. Investigations strain temperature response characteristics devices show...

An 8 × 16 wavelength selective switch (WSS) with full contentionless switching is proposed and experimentally demonstrated. Utilizing two chips of liquid crystal on silicon, the optical wavelengths can be switched, attenuated, or blocked among input ports output ports. The maximum insertion loss less than 14 dB; bandwidth tuning range from 50 to 5000 GHz. attenuation 0 15 dB, blocking value greater 27 dB. Compared previous reports, WSS in this letter a truly device highest number

This paper reviews atoms and ions in the upper atmosphere, including mesospheric metals Na, Fe, Mg$^+$, Si$^+$, Ca$^+$, K also non-metallic species N, N$^+$, O, H, considering their potential for astronomical adaptive optics. Na Fe are best candidates creation of polychromatic laser guide stars, with strongest returns coming from transitions that can be reached by excitation at two wavelengths. Ca$^+$ Si$^+$ have strong visible-light transitions, but require short wavelengths, beyond...

This paper mainly presents the study of preparation and application green vegetation concrete, pervious aquatic conservation concrete. The research includes material screening, mix proportion, operating points, construction process, scope. It has been observed that eco-friendly concrete can protect urban ecological system from departure balance contribute to realizing sustainable development.

The high proportion of new energy sources such as wind power and photovoltaic (PV) connected to the grid, coupled with a large number nonlinear users entering grid on scale, leads increasingly prominent quality problems stability caused by harmonics in grid. As result, accurate system harmonic impedance measurements are an important means solving some these problems. A non-characteristic current injection method is proposed obtain value accuracy at each frequency confirm series-parallel...