光学微瓶腔特性及温度传感应用研究

Characteristics and Temperature Sensing Application of Optical Microbottle Resonators

设计并测试了两种基于微瓶腔结构的温度传感系统。分别基于电弧放电法和自主装法制备了氧化硅材料(SiO2)和紫外光固化胶(UCA)聚合物材料微瓶腔,通过锥形光纤耦合的方式分析了两种微瓶腔基本特性,并测试它们在温度传感中的应用。实验结果表明,SiO2微瓶腔在温度上升时的灵敏度为11.13 pm/℃,在温度下降时的灵敏度为10.25 pm/℃;UCA微瓶腔在温度上升时的灵敏度为111.89 pm/℃,在温度下降时的温度灵敏度为102.02 pm/℃。两者在上升和下降时均保持很好的一致性,尤其UCA微瓶腔温度灵敏度比SiO2微瓶腔提升了10倍。本文传感器具有体积小、价格低、可塑性和重复性好、灵敏度高等优势,在温度传感领域具有潜在应用。

Optical resonators can limit light into a tiny space,enhancing the interaction between optics and materials.Optical microcavities supporting Whispering Gallery Modes(WGMs)have their advantages with miniaturization and easy integration.The WGMs in optical microcavities achieve optical confinement along the microcavities substance based on the principle of light total internal reflection,which can significantly strengthen light-matter interactions and increase quality factors.These advantages make them have great potential for high-sensitivity sensing applications.WGM optical microcavities have been prepared with various shapes,such as spheres,bottles,disks,rings,cylinders,hemispheres,and so on.In addition,optical microcavities have been also prepared with a variety of materials such as crystals,semiconductors,polymers and glass.Among them,polymer material has the advantages of being flexible,easy to process,and plasticity.It can be easy to be integrated on the optical fiber using the surface tension of the material to install natural formation.In addition,the polymer microbottle resonator is very well integrated.The result makes it possible for packaging the polymer microbottle resonator into a highly stable structure.In this paper,optical microbottle resonators prepared by silica material and Ultraviolet-Curable Adhesive(UCA)material are studied.The preparation methods for the two kinds of microbottle resonators are demonstrated.More specifically,silica microbottle resonators were prepared by the arc discharge method,and UCA polymer microbottle resonators were fabricated by the self-assembling technology.For silica microbottle resonators,the coating layer of a single-mode optical fiber was peeled off firstly and the end of the optical fiber was melted with high voltage discharge so that it formed a microsphere under the action of surface tension.Then,another optical fiber was moved close to the microsphere,and a microbottle resonator could be formed after multiple discharges around the area between the microsphere and the fiber.For UCA microbottle resonators,the polymer material UCA NOA61 is selected because the UCA material has a good light transmission and thermo-light coefficient,and can be cured under ultraviolet light.These properties make it easy to make a microbottle resonator.The self-assembling technology is used to fabricate UCA microbottle resonators.The UCA microbottle resonator was formed through the natural process.Firstly,a tapered fiber was made with the help of the heat-and-pull technique,then an appropriate amount of NOA61 droplets were transferred to the conical transition area above the fiber cone waist.As a result,NOA61 droplets would be self-assembled on the fiber cone because of its own gravity and surface tension to form a flat elongated structure.Subsequently,the NOA61 droplets attached to the tapered fiber were solidified by an ultraviolet lamp.Finally,the samples were placed into a temperature box to heat it and solidify them completely.In the test system,a broadband source in the communication band was a light source to excite the WGMs in the microbottle resonator.The output was detected by an optical spectrum analyzer.In addition,a tapered fiber,fabricated by using the heat-and-pull technique,is chosen as a waveguide to excite WGMs.The basic properties of the two kinds of different materials microbottle resonator were analyzed by a coupled tapered optical fiber.The quality factor of the silica microbottle resonator was 4.683×104 and the quality factor of the UCA microbottle resonator was 3.353×10^(4),correspondingly.The quality factors of the two kinds of microbottle resonators are very close.Temperature sensing applications based on the microbottle resonators were tested.The experimental results show that the sensitivity of the silica microbottle resonator is 11.13 pm/℃when the temperature rises and 10.25 pm/℃when the temperature drops.The sensitivity of the UCA microbottle resonator is 111.89 pm/℃when the temperature rises and 102.02 pm/°C when the temperature drops.Both of them maintain a good consistency when rising and falling.In particular,the temperature sensitivity based on the UCA microbottle resonator is 10 times higher than that of the Silica microbottle resonator.The demonstrated sensors based on our microbottle resonator have the advantages of small size,low price,good plasticity and repeatability,and high sensitivity,and have potential applications in the field of temperature sensing.