Remote System for Detection of Low-Levels of Methane Based on Photonic Crystal Fibres and Wavelength Modulation Spectroscopy
Figure 6
(a) Wavelength modulation converted to amplitude modulation in Wavelength Modulation Spectroscopy; (b) spectral contents of the optical signal: (i) laser unmodulated; (ii) laser modulated with no absorption; (iii) laser modulated with absorption.
