Determination of absorption coefficient by digital holographic measurement of optical excitation.

Digital holographic microscopy produces quantitative phase analysis of a specimen with excellent optical precision. In this study, this imaging method has been used to observe and measure induced thermal lensing by optical excitation. Previous studies have derived these phase shifts from intensity profiles for the determination of photothermal properties of very transparent materials. We have measured physical observables and determined the absorption coefficients of methanol and ethanol with improved precision and accuracy over traditional thermal lens spectroscopy methods.