Proposal of a simple digital lock-in amplifier for spectroscopy applications

This work shows that it is possible to develop a digital lock-in amplifier based on an Atmega2560 microcontroller for harmonic detection experiments in a wavelength modulation spectroscopy (WMS) system. Initial experiments carried out with carbon monoxide (CO) showed that the implemented lock-in was able to detect approximate concentrations down to 1% of CO at 1 atm.