SIMPLE DESIGNS TO MEASURE EFFICIENCY OF DIFFERENT TYPES OF MONOCHROMATORS

The monochromators are being widely used in most of the optical experi ments and the efficiency or throughput of a monochromator is an import ant parameter to be known. There are three types of monochromators com monly and commercially available, for example, Model-A: its entrance a nd exit slits are provided with two arms inclined at an angle of 90 de gree to each other, Model-B: it has been provided with entrance and ex it slits in line on opposite faces of the monochromator body, and Mode l-C: having entrance and exit slits side by side provided on the same face. In the present article we have described three designs to measur e the efficiency of the above mentioned three monochromators, for the light of a laser beam. In case this laser is replaced by a tunable dye laser the efficiency of the monochromators can be measured for the li ght of other wavelengths also. The designs are based on the principle of modulation radiometry.