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. .
