Figure 3
From: Interferometric measurements of refractive index and dispersion at high pressure
Analysis of the interference fringe spectrum obtained from the empty DAC with a white light. (a) The reflection spectrum from the flat gasket surface (blue line) is subtracted from the raw fringe spectrum (black square). In the subtracted spectrum (red circle), the residual intensity offset is determined with a smoothing method (blue dashed) and subtracted. (b) The envelope of the zero-mean spectrum (black square) is obtained with the Hilbert transform (red line). (c) The oscillation period (\(\Delta \nu\)) is obtained through a sinusoidal fitting (blue line) of the intensity-normalized spectrum (red circle). Pink dotted vertical line indicates the laser wavenumber (\(\nu _{L}\)).
