Grain size effect on the spectral characteristics of CV using photoacoustic spectroscopy

Photoacoustic spectroscopy (PAS) offers a unique method to measure optical absorption of materials in the powder form. In this work we employ PAS to study the change in the peak absorption of the dye crystal violet (CV) in the powder form, as a function of the grain size which was carefully controlled. It is observed that as the grain size is comparable to the incident radiation wavelength, there is an increase in the blue shift with decreasing the grain size.