absorption coefficient 1.4 0.8 g0.6 04 0.2 -0.2 400 500 600 700 800 wavelength(nm)300 400 500 600 700 800 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 intensity wavelength(nm) absorption coefficient