In this Letter, we have proposed an all-optical scheme for chiral particle separation with a microcylinder-pair system (MCPS) with a micrometer scale channel, applicable in microfluidic environments. By illuminating the MCPS with two counter-incident plane waves of orthogonal polarization, the electromagnetic chirality gradient can be generated. The MCPS can also enhance chirality-dependent lateral optical forces of the coupled fields so that the setup can shift trapping equilibrium positions for opposite-handedness nanoparticles and make the sideways motion observable.
View Article and Find Full Text PDFSurface enhanced Raman spectroscopy (SERS) utilizes the fingerprint features of molecular vibrations to identify and detect substances. However, in traditional single focus excitation scenarios, its signal collection efficiency of the objective is restricted. Furthermore, the uneven distribution of samples on the SERS substrate would result in poor signal stability, while the excitation power is limited to avoid sample damage.
View Article and Find Full Text PDFIn this Letter, we present a portable all-fiber fluorescent detection system based on metal-lined hollow-core fiber (MLHCF) for the ultra-sensitive real-time monitoring of mercury ions (Hg). The system employs a rhodamine derivative as the probe. The hollow core of the MLHCF serves as both the flow channel of the liquid sample and the waveguide of the optical path.
View Article and Find Full Text PDFIn this paper, an asymmetric structure optical fiber sensor is proposed to measure relative humidity (RH). The sensing structure is composed of splicing dispersion compensation fiber (DCF) and coreless fiber (NCF), and two sections of single-mode fiber (SMF) at both ends. Peanut shaped structure is used as a beam splitter at the input side, and the NCF is used as a beam combiner at the output side to form interference fringes.
View Article and Find Full Text PDFWe have manufactured an intensity modulated optical fiber SMDMS sensor with hydroxyethyl cellulose (HEC) hydrogel coating for simultaneous measurement of RH and temperature. The SMDMS sensor was manufactured by splicing single-mode fiber (SMF), multi-mode fiber (MMF), dispersion compensation fiber (DCF), MMF, and SMF in sequence to form a structure of SMF + MMF + DCF + MMF + SMF (SMDMS). The cladding of MMFs and DCF were corroded by hydrofluoric acid (HF) and coated with HEC hydrogel to excite a strong evanescent field and increase the sensitivity of the SMDMS sensor.
View Article and Find Full Text PDFA single core-offset Mach-Zehnder interferometer (MZI) coated with polyvinyl alcohol (PVA) for simultaneous measurement of relative humidity (RH) and temperature is proposed in this paper. The sensing structure is fabricated by splicing dispersion compensating fiber (DCF) and no-core fiber (NCF) and splicing two single-mode fibers (SMF) at both ends, where the core-offset is located at the splicing of SMF and DCF. A part of the cladding of DCF is etched to excite the high-order cladding mode (LP), and PVA is coated on the etched area.
View Article and Find Full Text PDF