the graphs in fig4 a to 4f a more whitish portion represents a peak where the light having the wavelength is present strongly as standing wave the peak position varies with the wavelength showing that the spectroscopy device of the present embodiment functions as a spectroscopy device fig5 illustrates spectral intensity of y direction polarized input light using the spectroscopy device shown in fig4 a to 4f in the graph shown in fig5 the coordinate of y direction distance is plotted on y axis and spectral intensity is plotted on x axis on the central axis of x direction of the spectroscopy device the y coordinate is normalized by the maximum value of the spectral intensity so that the graph shows relative values the graph clearly shows the position where the standing wave presents strongly with respect to each wavelength which is not clear in fig4 a to 4f for example the 440 nm wavelength has its peaks at three positions on y axis near 250 2000 and 4200 nm looking at the y coordinate from around 2500 to 4500 nm it is known that a peak of the 590 nm wavelength is present near 2700 nm and peaks of shorter wavelengths are present as the value of y coordinate is increased note that clear peaks of two wavelengths of 640 and 690 nm are not observed in the graph as clear from fig4 e and 4f this is because the two wavelengths have their peaks at positions away from the central axis of x direction of.