Temperature sensing is essential for human health monitoring. High-sensitivity (>1nm/°C) fiber sensors always require long interference paths and temperature-sensitive materials, leading to a long sensor and thus slow response (6–14 s). To date, it is still challenging for a fiber optic temperature sensor to have an ultrafast (∼ms) response simultaneously with high sensitivity. Here, a side-polished single-mode/hollow/single-mode fiber (SP-SHSF) structure is proposed to meet the challenge by using the length-independent sensitivity of an anti-resonant reflecting optical waveguide mechanism. With a polydimethylsiloxane filled sub-nanoliter volume cavity in the SP-SHSF, the SP-SHSF exhibits a high temperature sensitivity of 4.223 nm/°C with a compact length of 1.6 mm, allowing an ultrafast response (16 ms) and fast recovery time (176 ms). The figure of merit (FOM), defined as the absolute ratio of sensitivity to response time, is proposed to assess the comprehensive performance of the sensor. The FOM of the proposed sensor reaches up to 263.94(nm/°C)/s, which is more than two to three orders of magnitude higher than those of other temperature fiber optic sensors reported previously. Additionally, a three-month cycle test shows that the sensor is highly robust, with excellent reversibility and accuracy, allowing it to be incorporated with a wearable face mask for detecting temperature changes during human breathing. The high FOM and high stability of the proposed sensing fiber structure provide an excellent opportunity to develop both ultrafast and highly sensitive fiber optic sensors for wearable respiratory monitoring and contactless in vitro detection.

In graphene-based optoelectronic devices, the ultraweak interaction between a light and monolayer graphene leads to low optical absorption and low responsivity for the photodetectors and relative high half-wave voltage for the phase modulator. Here, an integration of the monolayer graphene onto the side-polished optical fiber is demonstrated, which is capable of providing a cost-effective strategy to enhance the light–graphene interaction, allowing us to obtain a highly efficient optical absorption in graphene and achieve multifunctions: photodetection and optical phase modulation. As a photodetector, the device has ultrahigh responsivity (1.5×107A/W) and high external quantum efficiency (>1.2×109%). Additionally, the polybutadiene/polymethyl methacrylate (PMMA) film on the graphene can render the device an optical phase modulator through the large thermo-optic effect of the PMMA. As a phase modulator, the device has a relatively low half-wave voltage of 3 V with a 16 dB extinction ratio in Mach–Zehnder interferometer configuration.

Opto-conveyors have attracted widespread interest in various fields because of their non-invasive and non-contact delivery of micro/nanoparticles. However, the flexible control of the delivery distance and the dynamic steering of the delivery direction, although very desirable in all-optical manipulation, have not yet been achieved by opto-conveyors. Here, using a simple and cost-effective scheme of an elliptically focused laser beam obliquely irradiated on a substrate, a direction-steerable and distance-controllable opto-conveyor for the targeting delivery of microparticles is implemented. Theoretically, in the proposed scheme of the opto-conveyor, the transverse and longitudinal resultant forces of the optical gradient force and the optical scattering force result in the transverse confinement and the longitudinal transportation of microparticles, respectively. In this study, it is experimentally shown that the proposed opto-conveyor is capable of realizing the targeting delivery for microparticles. Additionally, the delivery distance of microparticles can be flexibly and precisely controlled by simply adjusting the irradiation time. By simply rotating the cylindrical lens, the proposed opto-conveyor is capable of steering the delivery direction flexibly within a large range of azimuthal angles, from ?75° to 75°. This study also successfully demonstrated the real-time dynamic steering of the delivery direction from ?45° to 45° with the dynamical rotation of the cylindrical lens. Owing to its simplicity, flexibility, and controllability, the proposed method is capable of creating new opportunities in bioassays as well as in drug delivery.

Herein we propose a novel strategy to enhance surface plasmon resonance (SPR) by introducing a photonic cavity into a total-internal-reflection architecture. The photonic cavity, which is comprised of a highly reflective photonic crystal (PC), defect layers, and a gold (Au) film, enables Fabry–Perot (FP) resonances in the defect layers and therefore narrows the SPR resonance width in the metallic surface as well as increases the electric field intensity and penetration depth in the evanescent region. The fabricated sensor exhibits a 5.7-fold increase in the figure of merit and a higher linear coefficient as compared with the conventional Au-SPR sensor. The demonstrated PC/FP cavity/metal structure presents a new design philosophy for SPR performance enhancement.