The design of a reflection grating monochromator and its wavelength drive mechanism for the measurement of spectroscopic properties of a sample in near-ultraviolet to visible range spectra of light is presented. The discussion includes practical guidelines accessible to non-specialists who wish to design their own instrument. The basic characteristics and the design principles of such device are discussed, with emphasis on the key components. The system consists of a 32mm x 32mm in size, 1200 lines per mm reflection type grating, blazed at 250 nm and two 200mm focal length concave mirrors. Using a 10 μm wide entrance slit, a resolving power of 0.5nm has been demonstrated. A microcontroller based wavelength drive system is also discussed. Sensing of initial position, Scanning of wavelength spectra, stepping to desired wavelength and sensing of extreme positions are performed by the wavelength drive system. An effort is made to recall the fundamental laws and concepts of related optics.
Chemical and Pharrnaceuncal, Monochromator, grating, Wavelength drive
