The Basic Research Of Surface Plasmon Resonance Devices

The waveguide devices based on SPR (Surface Plasmon Resonance) technologyis simple structure, high sensitivity, insensitive to electromagnetic interference. Withthe development of nano-scale engineering and electromagnetic simulation method,SPR techniques present broad applications in biology, food analysis and medicalfacilities. Since surface plasmon wave is extremely sensitive to the surfacemorphology of metal strip, high precision is required in the fabrication of SPR devices.This thesis mainly covers several aspects as below:First, the lift-off method is widely used in SPR devices fabrication, which hassmooth surface but bad side wall that looks like shark`s fin blade. As the gold and theIodine, potassium iodide mixed solution occur chemical reaction, so we innovate anew fabrication process that etch Au film with PMMA (Poly methy1methacrylate) asits etching mask, which can obtain devices with smooth surface and steep side wall.Second, the material of sensor waveguide region is SU-8. The sensor sensingregion is fabricated by wet etch method with BP212as its etching mask. For the sakeof testing the effect on width variation of Au stripe, nine groups of SPR sensors isfabricated, which thickness is fixed at20nm and width is vary from2to18μm at2μm step.Third, the AFM images indicate that the roughness of the Au stripe is under1nmand the steepness is above85°which meet the requirement of SPW(Surface PlasmonWave) transmission. excited by optical fiber coupling method, the average insert lossof SPR waveguide is8dB/cm at1550nm when the thickness of Au stripe is20nmand width is6μm.Fourth, the test is under take in1550nm input wavelength and650nmwavelength respectively to the same SPR sensors. The testing results inform that theoutput intensity have larger diffraction in1550nm. The output intensity both havelarger change relatively when the sensing unit is20nm thick,6μm wide no matter theinput wavelength is650nm or1550nm, As a conclusion, the SPR refractive indexsensors have optimum sensing effect at input wavelength1550nm and a20nm thick,6μm wide sensing unit.