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1. Issues with fiber optic SPR sensors
Introduction to ATR-SPR system 1. Surface Plasmon Resonance (SPR) is a photoelectric phenomenon that is applied to quantitatively measure the refractive index of optical thin films (refractive index meters) with extremely high sensitivity and no need for calibration (label free). Its advantages are better than general fluorescence detection techniques and color chromatography, and it can dynamically study surface molecule interaction kinetics, which is applied in chemical and biological detection, including chemical gas detection, wastewater solution, pollution monitoring, immunotherapy, etc.
2. A typical SPR design is shown in Figure 1. Coat a 50nm gold or silver film (3) on one inclined surface (2) of the prism (1). A monochromatic coherent light source (4, TM mode) is incident on another surface and at different incident angles on the interface between the metal (2) and the prism (1). 1. Surface Plasmon Resonance(SPR) is an optic&photonic pheonmenon to be used for constant molecule measurement of refraction index unit( RIU, RU) of optical film, which is measured by RIU meter. SPR system has very high senstivity ,label-free character ,and can dynamically research the surface-molecule interaction kinetics. SPR system is applied to examination and measurement of chemical and biological molecule, which includes chemical gas examination and measurement , waste water solution, pollution control, mutation medicine, and so on. 2.The custom SPR design is like picture 1. One plate(1.2) of the prism(1.1) is covered with electrolyzed Au/Ag film. The simple and constantly frequent light source (1.4), TM mode, is the incident light. The simple and constantly frequent light enter one plate of the prism-typed all total reflection SPR(ATR-SPR). It"s reflected by the interface between the substrate and bottom of the prism. Because of the change of the index of surface, the reflected light has different reflected angle. And with different incident angle, the light incidents on the surface between the metallic film(1.2) and the prism(1.1). Surface enhanced Raman spectroscopy (SERS) is the process of creating periodic air holes on a silicon wafer using a yellow light etched photomask in the form of a photonic crystal (structural color). Due to the formation of periodic structures, photonic crystals have an enhanced reflection effect on several specific wavelengths due to a specific structure (photonic crystal spectroscopy). Under the enhanced reflection of several specific wavelengths, a specific color can be visually seen. Then, a gold thin film is plated on the surface of the photonic crystal, mainly by setting the thickness of the film, which only enhances the reflection on specific wavelengths, making the effect of the photonic crystal more obvious. Therefore, it is called surface coating enhanced photonic crystal. Raman spectroscopy The Raman scattering spectrum compares the frequency spectrum of incident light with the frequency spectrum of reflected and scattered light. The vibrational energy of molecular bonding vibration is 3RT/2 kinetic energy from gas dynamics theory at room temperature, followed by+RT rotational energy from diatomic molecule rotation at room temperature, and+RT vibrational energy from molecular bonding vibration at high temperature Generally speaking, Mohrs heat, with a monatomic molecule 3R/2=12.465 J/mol and a diatomic molecule 5R/2=20.775 J/mol, only becomes apparen