Development of a spectrometry system using lock-in amplification technique

Abstract

Raman spectroscopy and optical second-harmonic (SH) spectroscopy has a very important role in studies of optical properties of materials. Our goal is to build a spectrometry system to measure weak optical signals such as Raman scattering and surface SH signals. We studied to improve an old Double Grating Spectrograph GDM-1000 (Carl Zeiss, Jena, Germany) for wider range of wavelengths and transformed it successfully into a spectrometry system coupling with computer using Lock-in amplification technique. By this spectrometry system we can now obtain weak optical signals, for example, Raman Spectra of Vietnam petrol extracts excited by not only an 2W Argon laser but also by a 30mW He-Ne laser.