Spectral modulation

Figure 21. Theoretical (filled symbols) versus observed fluxes at SILVA CEA lab (open symbols). Without spectral modulation (bottom), with modulation at 589nm (middle) and with modulation at 589 and 569nm (top) Bellenger, 2002.

Spectral modulation in the NIR region has been reported for the complex [Ru(L8)3]2+ which undergoes six ligand-centered reductions, two per ligand.17 It initially shows no absorption... 

As a consequence of the spectral modulation, the temporal width of the laser pulse is modified and a linear frequency sweep (chirp) is introduced. The modulated pulse duration is... 

The fiber optic sensors utilize an extrinsic Fabry-Perot interferometer to spectrally modulate light in proportion to pressure, temperature, or refractive index variations. Because they are based on spectral modulation instead of amplitude modulation, they are not affected by such common problems as fiber bending, connector losses, and aging. 

Wang, X., Acousto-Optic Tunable Filters Spectrally Modulate Light Laser Focus World 1992, 28, 173-180. 

In spectral interferometry, the interference in the spectral domain is exploited. The spectral modulation period is essentially determined by a time delay. This is at the heart of Fourier transform infrared spectrometers (FTIRs). 

Interestingly, the amplitude of spectral modulation increased toward higher wind speed and wave number (Fig. 3). This trend is opposite to the prediction of the relaxation theory that assumes a monotonic increase in... 

Also present in the detected spectra is a modulation clearly noticeable for the point source (green). For comparison. Fig. 5.7 (right) shows the detected spectra for three positions in the sky, where a similar modulation appears. Again, this is due to the dirty beam, which is wavelength dependent as the frequency (or wavenumber) increases, the dirty beam narrows and so do the side lobes. By selecting a spatial position and increasing the frequency, the variation of size of the dirty beam causes a spectral modulation. 

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