The SPECTROMETER (not pictured) detects changes in the returning light, revealing the concentration of target molecules.
A TILTED GRATING reflects certain wavelengths known as resonances out of the core. These resonances depend on the properties of the grating and the fiber’s surface.
When TARGET MOLECULES bind to receptors on the surface of the fiber, they shift the wavelength and intensity of the resonances
A laser transmits light into the fiber’s CORE.
A GOLD MIRROR on the tip of the fiber reflects the light remaining in the core back to a spectrometer at the opposite end.