title: Continuous-wave photothermal deflection spectroscopy with fundamental and harmonic responses.
abstract: A diffraction theory of continuous-wave photothermal deflection (PD) spectroscopy with fundamental and harmonic responses is presented. The displacement of the probe beam centroid is found to be a rigorous measurement of PD effect, which leads to a set of analytical solutions to the fundamental and the second-order harmonics. Harmonics are caused by the diffraction of the probe beam in the mirage region, which could not be handled by geometric-optics theory. This theory can be used to study bulk materials, thin films, and layered-structure samples. Experimental results are in good agreement with the theory.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.forename: Cheng
authors.initials: C
authors.lastname: Hu