[spectroscope]Can produce and observe the spectrum instrument, it is also called the spectrometer. It can also be used as a simple wavelength measuring instrument. There are many types of spectrometers. Besides the difference of operational principles, there are different radiation lines that are detected. The interval of radiation frequency is from infrared light to roentgen red (X light).
A simple beam splitter is: from the S light source the light emitted through a slit into a narrow beam of light, a convex lens and into parallel light (narrow slit in focal plane convex lens plane), the parallel light through a prism dispersion, for the same color (wavelength) radiation parallel to these rays through a convex lens can put the light do not focus at different locations on the screen, then on the screen showing a row according to the color spectrum wavelength length arrangement, this is the spectrum emitted by the light source, the light source and the spectrum of different elements are different. Most of the present lenses replace the lens prism with the diffraction gratings. If the surface of the grating is concave (concave grating), the grating itself has a focusing effect, so the lens system can be cancelled.
The resolution of prism varies with wavelength, and the resolution is larger in short wave. That is, prism splitting has "non uniformity". The spectrum of chromatography is "non uniform spectrum". This is the biggest shortage of prism.
Production: with special tools (such as diamonds), a large number of tight and parallel grooves are engraved on hard and polished optical planes. This motherboard, available liquid resin to replicate the grating in the. The grating has a plane transmission grating, a plane reflection grating and a concave reflector grating. Probably not high quality grating is easy to produce scattered radiation and the ghost line (Ghost lines).
Concave grating (concave grating)
A grating made of a series of parallel grooves on the inner side of the hemisphere with a radius of R, which is mostly used in the photoelectric direct reading spectrometer. Because such grating has the function of focusing and splitting, the optical components such as converging lens are not needed in the spectroscopic system. The light loss is small and the cost is low.