Side-polished Plastic Optical Fiber SPR Sensor Based On Gold Sputtering

Surface plasmon resonance(SPR)is a physical optical phenomenon that uses light evanescent waves to resonate with metal(SPW)to determine the refractive index change of the analyzed item As the SPR sensor is very sensitive to changes in the refractive index of the environment,its quick response can resist electromagnetic interference and small size.It is widely used in environmental water quality monitoring and disease prevention and control.The unique advantage of the fiber optic SPR sensor system is that it can change the geometry of the fiber probe,and has the advantages of low preparation cost,remote detection,reusability and recycling.It has become a research hotspot in recent years.This paper mainly studies the side marker polishing optical fiber surface plasma sensor,which not only has the advantages of simple structure,low cost and easy preparation,but also has great potential in practicality.In this paper,through further modification and processing of plastic optical fiber,a high.performance,low.cost side.polished plastic optical fiber gold film SPR sensor was prepared,and its design,preparation,and refractive index sensing response characteristics were optimized,and finally explored.The sensitivity of the new SPR sensor.This article mainly includes the following:1)Through derivation research on SPR theory,the preparation process of the side.polished gold sputtering POF-SPR sensor is optimized.Considering the ease of design and processing difficulty of the plastic optical fiber geometry,the U.shaped structure and the side polishing method are combined,and the mechanical optical fiber polishing method is used to pass the rough polishing,fine polishing,ethyl acetate immersion and other methods to the plastic optical fiber.The fiber core is processed to provide the fiber evanescent field substrate for the next research and preparation of the POF-SPR refractive index sensor.2)The plastic optical fiber core is coated with gold.The magnetron sputtering coating machine is energized by pressure to cause argon atoms to bombard the gold target.A gold film with a thickness of nanometers is deposited on the exposed plastic optical fiber corewindow to prepare A plasmon resonance index sensor on the surface of the plastic optical fiber polished on the side.3)A POF-SPR test platform was built to test the refractive index response performance of the U.shaped side polished gold sputtered POF-SPR sensor prepared in this paper.The performance of the sensor was analyzed and discussed through the sensitivity index.It is found that when the refractive index of the external liquid changes from 1.333 to 1.406,the resonance wavelength position changes from 528.9nm to 625.4nm,and its sensitivity is 1233 nm / RIU.