Abstract
A lock-in amplifier for chopped optical signals is described. It is simple but effective. Its special features are: (a) The system reduces the effect on the experimental results of fluctuations in the light source intensity. (b) The locking in can be carried out with a chopper operating with a variable frequency. (c) A series of odd harmonics synchronous with the chopper can be chosen to be highly rejected. In particular, a signal due to pickup of the 3rd harmonics can be made small.

This publication has 0 references indexed in Scilit: