Raman spectroscopy has become an increasingly important tool for measuring and identifying the chemical composition and molecular structure of many materials. Traditional applications of Raman spectroscopy focus on signals that are hundreds of wavenumbers away from the excitation laser line due to the limitations of available filters for blocking the intense Rayleigh scattered laser light. Traditional notch filters tend to have bandwidths that are hundreds of wavenumbers wide and even the narrowest edge filters still block much of the Raman signal below 100 cm-1.As a result, the study of ultra-low frequency Raman spectra in the <100 cm-1 region could only be done by complex and high cost multi-stage spectrometer systems.