Design And Characterization Of Surface Plasmon Sensors Based On Metallic Nano-arrays

Surface plasmon have attracted widely attention due to exotic dynamic properties including optical negative refraction and perfect lensing.Localized or surface plasmons belong the origin of these properties,exciting free electrons in metals to cause collective oscillations,which is enhancing the local field be beneficial to the interaction of light and matter.As a consequence,potential applications in surface-enhanced raman scattering,surface enhanced fluorescence and sensing had been excavated.Recently,a wide range of applications has been developed for use of SPR biosensors in the biomedical field.Compared to conventional equipments,SPR biosensing have some obvious advantages in its label-free and real-time,thus is regarded as a promising diagnostic tool for diseases.These characteristics as portable,cost-effective,easy-to-use for SPR biosensors are able to use in practical application,which also enables rapid and accurate diagnosis.Most recently,some researchers have reported the plasmonic sensing components with micro-nanoscale and miniaturized the dimension of the systems to satisfy growing demand.In order to solve sensing performances and portability of the sensor,this thesis focuses on designing and characterization of surface plasmon sensors based on metallic nanoarrays.Therefore,our work of this thesis can be summarized as follows.(1)A perfect absorber plasmon sensor with high sensitivity based on a ring and disk array(D/RA)structure is designed.The interaction of the ring and disk array can easy to excite electric field of surface plasmon resonance,which simultaneously have interaction with magnetic resonances formed by a sandwich structure to achieve the impedance match with free space.To systematically investigate the optical properties and sensing performances of the D/RA-S-M,a 3-D FDTD simulation was employed.The impedance of the ring and disk array by adjusting some parameters of structure match with the surrounding air,which enables resonant wavelength of the plasmonic perfect biosensor dual-band and 1550 nm respectively.The dual-band perfect biosensor revealed that a maximum absorbance of 99.6% and a narrow FWHM of 12 nm can be operated as a refractive index sensor,which has a high sensitivity of754 nm RIU and the figure of merit(FOM)to 62.The sensitivity as high as 1376 nm/RIU and FOM of 65 was provided as sensing at the wavelength of 1550 nm.These results are expected that the dual-band and 1550 nm plasmonic perfect biosensor make it a promising candidate for great potentials in the fields of absorbers and sensing.(2)We design an integrated plasmonic biosensor on a vertical cavity surface emitting laser(VCSEL).The resonant wavelength of the nanohole array(NHA)by adjusting its parameters can realize to match with the emission peak wavelength of the VCSEL.The emission peak width of the VCSEL about 1.5 nm means can be achieved more intensity difference in the same shift of wavelength than other light equipment such as LED.Monitoring the light output intensity can be measured the refractive index representing the concentration of the molecule bound on the integrated plasmonic biosensor.The results show that the relative intensity difference is up to 98.8% for detecting molecular conventional concentrations.What's more,the size of the VCSEL in length and width are the regular specification of hundreds of micrometers.Our study could offer theoretical guidance for device design of the integrated sensor.