Eliminating thermal effects in z-scan measurements of thin PTCDA films

Accurate measurements of the thermal diffusivity of thin films and thin filaments using lock-in thermography

In lock-in thermography the thermal diffusivity can be obtained from the slope of the linear relation between the phase of the surface temperature and the distance to the heating spot. However, in the case of thin samples, the linearity is not found. In this work we identify heat conduction to the surrounding gas as the mechanism responsible for the lost of linearity. Accordingly accurate measu...

Exciton emission in PTCDA films and PTCDA/Alq3 multilayers

We investigate the exciton emission in 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) thin films and PTCDA/aluminium-tris-hydroxyqinoline sAlq3d multilayers by photoluminescence spectroscopy in the temperature range from 10 to 300 K. The films are grown by organic molecular beam deposition on Si(001) and PyrexTM substrates at high vacuum. The obtained temperature dependence of the differ...

Z-Scan Measurements of Optical Nonlinearities

Ultrafast Nonlinear Optical and Optical Limiting Properties of Phthalocyanine Thin Films Studied Using Z-Scan

We have investigated the nonlinear optical properties, optical limiting thresholds, and figures of merits for five different phthalocyanine thin films, achieved through doping in PMMA polymer, using the Z-scan technique at 800 nm with 2 ps laser pulse excitation. From the open-aperture Z-scan data we derived that these molecules exhibit strong two photon absorption (2PA) with the nonlinear abso...

Indentation measurements on thin films

Thin films have an important part to play in modern technology. It is difficult to characterize the mechanical properties of thin films because the films cannot usually be investigated separately from the substrate. One of the few methods that can be used for such investigations consists in making an indentation in the film by applying an extremely small and accurately controlled force while at...