A new flexible method to fabricate a temperature sensor based on polymethylmethacrylate (PMMA) optical microbubbles, using a volume-controllable pipette, is demonstrated. The high quality factor of the cavity is guaranteed by the smooth wall of the microbubble. The shape and refractive index of the microbubbles change with the surrounding temperature, which leads to the obvious displacement of the whispering gallery mode transmission spectrum. As the surrounding temperature increases, the spectrum undergoes a significant blue shift, hence the microresonator can be used for temperature sensing. A sensitivity of 39 pm °C−1 is obtained in a PMMA microbubble with a diameter of 740 µm. This work suggests a new convenient approach to achieving high-quality flexible microscale sensors.

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We demonstrate carbon quantum dots (C QDs)-coupled graphene/silicon (Si) Schottkyjunction photodetectors with ~290 mA W −1 responsivity. The C QDs were fabricated by carbon evaporation, which facilitated easy control of the distribution and pattern of the QDs can be easily controlled by a mask. The photoresponsivity was enhanced by 4.3% when the C QDs were coupled with the graphene/Si Schottky-junction photodetectors. The wideband spectrum response flatly covers the visible spectrum. The response time is less than 2 µs, which is better than most detectors based on graphene-Schottky or QDs structures. This work demonstrates a feasible approach for improving the performance of graphene-based photodetectors, suggesting an alternative architecture for QDs graphene photodetectors.

We experimentally investigate a stable freestanding whispering gallery mode (WGM) microlaser based on polymer microdisk formed by a ~500 µm diameter microfiber knot. A quality factor of about 14 700 and a relatively low lasing threshold with about 38.0 µJ/ pulse are demonstrated in this structure. When a polymer microdisk is pumped by a 532 nm wavelength pulse laser, WGM lasing with a free spectral range (FSR) of 0.15 nm is observed from the polymer microdisk laser. This work provides a convenient and efficient approach to achieving a WGM microlaser based on a polymer microdisk and collecting the output light.

We propose and demonstrate a coating-enhanced dual-microspheric structure fiber sensor that measures temperature and refractive index simultaneously. The claddings of the two microspheric structured fibers are spliced together and the ends of the fibers are coated with a layer of gold film to increase reflection, thereby forming a dual-microspheric structure sensor head. Our experimental results show that the temperature sensitivity and the refractive index can reach 65.77 pm °C−1 and −19.7879 nm RIU −1 , respectively. Compared with the uncoated sensor, the refractive index sensitivity is significantly improved by the gold film. This work suggests a low-cost, high-resolution and convenient fiber-based method to achieve multifunctional sensing applications.