Photothermal imaging of optical polymers, polymer metal interfaces and photodegradation of polyvinyl chloride

Photopyroelectric spectroscopy (PPES) is a relatively new nondestructive photothermal technique that uses a pyroelectric sensor placed in intimate contact with thin film samples to record the photogenerated thermal waves transmitted by the sample. In this thesis it is demonstrated that photopyroelectric spectroscopy is capable of recovering profiles of optical absorptivity in micron scale thick polymer laminates with submicron depth resolution. The pyroelectric method has also been used to characterize adhesion at polymer/metal interfaces from the photothermal impulse response using both the transmission and inverse detection geometries. The PPES technique can also map the distribution of polyene bands created during photodegradation of polyvinyl chloride. Results are obtained in the frequency and time domains using conventional lock-in detection, excitation with wideband time domain sweep waveforms and wideband homodyne techniques. The experimental photothermal results can be modeled using the linear properties of heat conduction to obtain quantitative values of the optical and thermal properties of the samples

Flight Test of a Video-Based Automatic Station-Keeping System: Tracking Targets on the Ground

Peer reviewed: YesNRC publication: Ye

Flight Test of a Video-Based Automatic Station-Keeping System: Tracking Targets on the Ground

NRC publication: Ye