A new type of X-ray fiber dosimeters is proposed that is based on the X-ray response of CsPbBr3 perovskite-quantum-dots (PQDs) activated silica fiber. Such a fiber sensor is constructed by covering a multimode silica fiber with PQDs embedded glass powders using a transparent high-temperature glue. Under X-ray irradiation, the fiber sensor emits bright green light at 525 nm, which can be readily recorded by a CCD spectrometer. The integrated radioluminescence intensity has an excellent linear response to the X-ray dose. Study is given to the fiber sensor concerning its thermal stability in a temperature range of room temperature up to 300°C, resistance to water erosion, and prolonged X-ray irradiation. The results verify that the proposed fiber sensor has the advantages of good thermal stability, chemical durability, and radiation hardness. The studied X-ray fiber sensor holds promise to be used in a real-time, in-situ, and remote radiation dose monitoring.

We propose and demonstrate a dual-channel microfluidic sensor based on a side-hole fiber (SHF) with two long-period fiber grating (LPFG) structures. There are two air holes in the SHF, which are natural microfluidic channels. We fabricate two LPFGs (long-period gratings LPG-A and LPG-B) in the SHF with the resonance wavelengths of 1268.7 nm and 1385.8 nm, respectively. Results show that the refractive index sensitivities of LPG-A and LPG-B are ?76.0 nm/RIU and ?71.1 nm/RIU, respectively. One can measure the refractive index of liquid samples in two channels simultaneously. The proposed dual-channel microfluidic sensor has advantages of good linearity response, fluidic technology compatibility, and easy light input/output coupling and system integration, which helps the sensor to have a potential application in environmental detection and food safety detection.

We propose and demonstrate single fiber dual-functionality optical tweezers based on a graded-index multimode fiber. By using the multi-angle fiber grinding and polishing technology, we fabricate the multimode fiber tip to be a special tapered shape, contributing to focus the outgoing beam with a large intensity gradient for the first functionality—three-dimensional contactless trapping of a microparticle. By adjusting the radial direction offset between the lead-in single mode fiber and the graded-index multimode fiber, we perform the second functionality—axial shift of the trapped microparticle with respect to the fiber tip without need of moving the fiber probe itself. It is convenient for practical applications. The theoretical and experimental results about the relationship between the radial offset and the equilibrium positions of the microparticle have the good consistency. Tailoring the trap and axial shift of the microparticle based on the graded-index multimode fiber provides convenient avenues for fiber optical tweezers applied in practical researches.

We propose and demonstrate a novel single fiber optical tweezer based on a graded-index multimode fiber (GIMMF), which works with a free length GIMMF (>30 cm). We achieve a three-dimensional stable trap of yeast cells by using the GIMMF optical tweezers. Compared with the single-mode fiber optical tweezers, the GIMMF optical tweezers possess large optical trapping forces. Owing to the freedom of the GIMMF length, the fabrication of the GIMMF optical tweezers is simple, repeatable, and highly efficient. The GIMMF tweezers have the penitential to become a new member of the single fiber optical tweezers family and have a wide range of applications in the medical and biological cytology fields.