Physical measurement apparatus for absolute measurement of refractive index - monitors position of mirror reflecting light refracted by system contg. specimen back into system

摘要

The apparatus for the absolute measurement of refractive index reflects a measurement beam, which has already been deflected by a light refracting system contg. the measurement specimen (6) and a reference substance, back into the system via a retroreflecting mirror. - The mirror position is monitored by a photodiode (8) to which part of the retroreflected light is passed via a beam divider (3) in the optical path between the light source (1) and the light refracting system. The mirror position difference angle with and without the refracting system equals the system's deflection angle and hence forms a direct measurement parameter for the absolute value of the refractive index.