Study the Optical Properties of Noble Metal (Au, Ag, and Cu) Thin Film Biosensors Based on Surface Plasmon Resonance Performance by a Simulation Program

In this work, we studied the effect noble metal thicknesses, namely gold (Au), silver (Ag), and copper (Cu) on the surface plasmon resonance (SPR) characteristics for sensitive optical sensor and biosensor applications. SPR spectra for Au, Ag and Cu were widely studied in the Fresnel equation to calculate the total reflection, the wavelength (lambda) range from 500 nm to 700 nm with the angle of incidence (theta) ranging from 0 degrees to 90 degrees and thickness of the film (d) reaching from 30 nm to 70 nm. Analysis simulation (in MATLAB) has been made for SPR of three metals placed on the N_LASF9 glass prism and the sensing medium is the air. The properties of the angle of resonance theta(SPR) have been calculated from plotted reflectance via incident angle theta(SPR). The results give efficient detection in a change of reflection (R) and full half width maximum FWHM. The minimum reflection was obtained (0.003 a.u.) at wavelength 700 nm and thickness d= 50 nm for gold Au at Delta n = 0.0. The best FWHM was recorded at the wavelength (500 nm) at thickness (70 nm) for silver at Delta n = 0.0, which was equal (0.1 nm).