Fiber-coupled microscope systems use single mode optical fibers to deliver light from the laser to the microscope. The transmitted light maintains a TEM00 mode and preserves its Gaussian character independently of the laser power attenuation, thus allowing diffraction limited resolution.
Multi-mode optical fibers in the detection beam path enable the transmission of up to 90% of the Raman signal. For comparison, an Al-mirror based optical system using three mirrors achieves only about 78% efficiency in light transmission at 532 nm excitation wavelength. If the number of mirrors used increases, the light transmission efficiency drops further. Therefore the usage of optical fibers is particularly apt for ultrahigh-throughput microscope systems.