We fabricate mode converters by directly writing long-period gratings in a two-mode fiber with CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser. These allow the fundamental LP xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> to be converted any of four higher order cylindrical vector modes or xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> modes. The transmission characteristics these devices are insensitive temperature...

Tungsten disulfide (WS2), as a representative layered transition metal dichalcogenide (TMDC) material, possesses important potential for applications in highly sensitive sensors. Here, sensitivity-enhanced surface plasmon resonance (SPR) sensor with film modified by an overlayer of WS2 nanosheets is proposed and demonstrated. The SPR sensitivity related to the thickness overlayer, which can be tailored coating ethanol suspension different concentrations or number times repeated post-coating....

A high-sensitivity vector magnetic field is proposed and demonstrated. The sensor consists of a side-polished-fiber (SPF)-based surface plasmon resonance (SPR) structure integrated with ferrofluid. Because the high refractive index sensitivity SPR scheme outstanding magneto optical properties ferrofluid, shows (up to 598.7 pm/Oe) intensity. Moreover, owing non-circular-symmetric geometry SPF non-uniform distribution ferrofluid around SPF, exhibits -5.63 nm/deg orientation field. sensor,...

Abstract Bound states in the continuum (BICs) are ubiquitous physical phenomena where such occur due to strong coupling between leaky modes side lossy systems. BICs meta-optics and nanophotonics enable optical mode confinement strengthen local field enhancement nonlinear optics. In this study, we numerically investigate second-harmonic generation (SHG) vicinity of with a photonic structure comprising one-dimensional nanogratings slab waveguide made lithium niobate (LiNbO 3 , LN). By breaking...

Abstract Second harmonic generation (SHG) with a material of large transparency is an attractive way generating coherent light sources at exotic wavelength range such as VUV, UV and visible light. It critical importance to improve nonlinear conversion efficiency in order find practical applications quantum source high resolution microscopy, etc. Here enhanced SHG up 10 −2 % SH 282.7 nm under 11 GW/cm 2 pump intensity via the excitation anapole lithium niobite (LiNbO 3 , or LN) nanodisk...

Abstract 2D graphene has attracted extensive attention as a promising candidate for high‐performance photodetectors because of its superior optoelectronic properties. However, the realization high‐sensitivity broadband remains challenge. Lithium niobate (LiNbO 3 ) advantages spontaneous polarization, high dielectric constant, and voltage electric coefficient, it can improve photoelectric detection characteristics by polarized doping. In this work, n‐ p‐doping is demonstrated at same time...

A long-range surface plasmon resonance (LRSPR) sensor with enhanced performance has been theoretically calculated and experimentally investigated for biosensing applications. The LRSPR-based is fabricated by employing a side-polished multimode fiber as waveguide MgF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> buffer layer beneath thin silver film supporting LRSPR excitation. Theoretical optimization based on transfer matrix method...

We propose a compact three-dimensional waveguide mode (de)multiplexer based on the configuration of two collocated asymmetrical directional couplers, formed with dissimilar single-mode cores placed alongside central rectangular three-mode core in horizontal and vertical directions, respectively. The waveguides are designed to allow LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11a</sub> xmlns:xlink="http://www.w3.org/1999/xlink">11b</sub>...

A novel fiber structure, coreless side-polished (CSPF) that is wrapped by polydimethylsiloxane (PDMS), demonstrated to be highly sensitive temperature because of the high refractive index sensitivity CSPF and large thermal optic coefficient PDMS. Our numerical experimental results show several dips in transmitted spectra PDMSW-CSPF originated from multimode interference (MMI) will blueshift with increase temperature. Furthermore, for such a PDMSW-CSPF, we investigate its sensing...

The fiber geometry, parameters and mode-guiding properties are crucial for realizing high-performance fiber-based sensors. In this work, we propose demonstrate a few-mode (FMF)-based surface plasmon resonance (SPR) biosensor. FMF-SPR sensor was fabricated via side-polishing coating thin layer of gold film, on the basis optimization thickness film mode selection, which were performed with finite element method. refractive index (RI) sensing performance three such sensors different residual...

A novel strategy to modify the plasmonic interface by spin-coating an overlayer of graphene oxide sheets (GOSs) on top surface plasmon resonance (SPR) sensor is proposed and demonstrated. Thanks excellent electrical conductivity, large area, high-refractive index GOSs layer, GOSs-modified SPR (GOSs-SPR) achieves improved sensitivity in detection bulky refractive solutions bovine serum albumin (BSA) solutions. The maximum 2715.1 nm/RIU achieved three spin-coatings shows enhancement 20.2% than...

We demonstrate a passively mode-locked fiber laser that incorporates two-mode Bragg grating (FBG) for transverse-mode selection. By controlling the polarization state of light in cavity, can provide continuous-wave output at LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode, xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> or their mix, which correspond to different reflection wavelengths FBG. When is mode-locked, it generates...

In this paper, a side-polished fiber (SPF) coated with molybdenum diselenide (MoSe2) is proposed, and its characteristic of relative humidity (RH) sensing investigated. It found in the experiment that an enhancement RH sensitivity (0.321 dB/%RH) can be achieved very wide range 32%RH to 73%RH for proposed MoSe2 SPF (MoSe2CSPF). also shown MoSe2CSPF has rapid response 1s recovery time 4s, which makes sensor capable monitoring human breath. The experimental results suggest promising potential...

We propose and demonstrate a novel strategy to modify the plasmonic interface by using thin layer of halloysite nanotubes (HNTs). The modified surface plasmon resonance (SPR) sensor achieves greatly improved sensitivity because large area high refractive index HNTs significantly increase probing electric field intensity hence measurement sensitivity. More significantly, thickness can be tailored spraying different concentrations ethanol suspension. proposed sensors show significant...

We demonstrate a mode demultiplexer with two cascaded few-mode polymer waveguide directional couplers fabricated on the same substrate along horizontal and vertical directions, respectively. The three waveguides that form have core size. are designed to provide complete power transfer for LP(11a) LP(11b) modes, LP(01) staying in central incorporates biconical taper suppress any remaining LP(11) modes. A typical demultiplexer, which is 18.5 mm long, shows coupling ratio higher than ∼96%...

In this work, we demonstrate a highly-sensitive vector magnetometer based on few-mode-fiber-based surface plasmon resonance (SPR) sensor functionalized by magnetic nanoparticles (MNPs) in liquid. To fabricate the sensor, few-mode fiber is side-polished and coated with gold film, forming an SPR that highly sensitive to surrounding refractive index. The operates mechanism whereby intensity orientation of external field alters anisotropic aggregation MNPs thus index around device. This, turn,...

One important use of molybdenum disulfide (MoS2) could be in making sensing and detection devices with optical chip or fiber. Here, MoS2 nanosheets coated on side-polished fiber (SPF) is proposed, which can enhance the localized interaction between evanescent light core nanosheets, this motivate greatly performance. Moreover, nanosheet possesses exceedingly high surface/volume ratio. By combining fiber, humidity characteristics has been demonstrated. The transmitted power (OTP) MoS2-based...

We propose the broadband mode-selective coupler (MSC) formed with a side-polished six mode fiber (6MF) and tapered small core single-mode (SC-SMF) or an SMF. The MSCs are designed to allow LP 01 in SC-SMF SMF completely couple , 11 21 02 31 12 modes 6MF over wavelength range. phase-matching conditions of satisfied by tapering specific diameters. fibers residual thickness using wheel polishing technique. effective indices measured prism coupling method. provide high ratio purity. High...

Recently, nonlinear photonics has attracted considerable interest. Among the effects, second harmonic generation (SHG) remains a hot research topic. The recent development of thin film lithium niobate (TFLN) technology superior performances to conventional counterparts. Herein, this review article reveals progress SHG based on TFLN and its integrated photonics. We mainly discuss compare different techniques TFLN-based structures boost assisted by localizing light in nanostructures structured...

A surface plasmon resonance (SPR) sensor based on side-polished two-mode fiber (TMF) coated with indium tin oxide (ITO) film is proposed. ITO enables tuning of wavelength the through changing its carrier concentration. The advantages TMF and are combined in sensor, which can achieve high sensitivity plasma frequencies near-infrared region. impact thickness residual sensing performance numerically investigated LP01 LP11a modes coupled to specific modes. results show that locates 1500-2200 nm...

A novel fiber structure, coreless side-polished (CSPF), is proposed and investigated to implement multimode interference (MMI) high sensitive refractive index (RI) sensors. For such CSPF, the part of cladding core a single-mode are off so as make remained D-shaped waveguide. The excitation evolution MMI in CSPF simulated numerically. simulation results show that high-order modes excited within waveguide mainly TE0,1 (TM0,1)~TE0,6 (TM0,6) modes. Moreover, RI sensing characteristics influences...

Second harmonic generation (SHG) is an important nonlinear process which critical for applications, such as optical integrated circuit, microscopy, laser, etc. Many challenges remain in the improvement of conversion efficiency, since typical value only 10−5 nanostructures. Here, we theoretically demonstrate a periodic structure consisting lithium niobate (LN) bar and LN disk, on nanoscale (~300 nm) thin-film platform, proposed highly efficient SHG. By breaking symmetry, Fano resonance with...

In this work, a sensitivity-enhanced surface plasmon resonance (SPR) sensor, which is integrated with MoSe2 as modification overlayer, proposed and investigated. The sensor constructed by physically depositing onto the of conventional SPR based on Krestchman configuration. Thanks to commendable properties including high carrier mobility, refractive index (RI), large area, so forth, adding an overlayer within certain thickness can effectively improve RI sensitivity. Experimental results show...