A Software-Based Lock-in Amplifier for Optical Spectroscopy Applications

This works describes the development of a low computational cost software capable of applying the signal correlation technique which is used by lock-in amplifiers, applying this processing in the whole optical spectrum of an optical spectroscopy experiment. The synchronous (or lock-in) amplifier utilizes as its main characteristics the ability to obtain the measured signal immersed in noise which has superior signal amplitude. The software was developed in C# programming language. From the data obtained by a StellarNet spectrometer, it is shown that the software is capable to apply lock-in processing simultaneously in all 2050 points that compose the optical spectrum. Two performance tests were conducted to recover the spectral emission profile of a low intensity yellow LED, submitted to two different emulated optical noise: a regular intensity green LED and a high intensity white light source. Preliminary results shows the efficacy of the software and the viability of embed platform for prototyping which allows the application of optical spectroscopy techniques without the need of external luminosity control.