The possibility of using a minimal-volume photoacoustic cell to perform spectroscopy of samples is discussed. It is shown that this alternative signal-to-noise-enhanced photoacoustic configuration allows one to obtain both absorption and transmission spectra with minimal experimental arrangement and cell machining requirements. The theoretical model is presented, the use of which is exemplified by a complete optical and thermal characterization of leaves.

Using two different photoacoustic techniques for a two-layer system of variable thickness, we show that the thermal diffusivity and the thermal conductivity are completely determined, based upon the efFective-sample model widely used in heat-transfer problems. A procedure to establish a standard photothermal technique for measuring both the thermal diffusivity and the thermal conductivity is also discussed.

A model for the effective thermal conductivity of metal-nonmetal particulate composites J. Appl. Phys. 111, 044319 (2012) Thermoelectric efficiency of topological insulators in a magnetic field J. Appl. Phys. 111, 07E319 (2012) Effective medium formulation for phonon transport analysis of nanograined polycrystals J. Appl. Phys. 111, 014307 (2012) On the accuracy of classical and long wavelength approximations for phonon transport in graphene J. Appl. Phys. 110, 113510 (2011) A study of the impact of dislocations on the thermoelectric properties of quantum wells in the Si/SiGe materials system J. Appl. Phys. 110, 114508 (2011) Additional information on J. Appl. Phys. In this paper the use of the so-called open photoacoustic cell for thermal characterization of two-layer systems of variable thickness is described. It is shown that the thermal diffusivity as well as the thermal conductivity are completely determined, based upon the effective sample model widely used in heat-transfer problems.

A theoretical and experimental study of the influence of planar thermal barriers on photothermal reflectance microscopy signals is presented. An analytical solution is developed for the problem of vertical barriers in a semi-infinite solid and the signal contrast obtained when scanning through the barrier is discussed as a function of the thermal resistance, the thermal diffusion length, and the pump and probe beam dimensions. The shape and the width of the signal perturbation introduced by the barrier is also analyzed. For the case of slanted barriers results of finite-element calculations are presented, and the main feature of the signal when going from vertical to slanted barriers is thus shown. Finally, the theoretical predictions are compared with measurements made on Fe sintered samples. Scanning through grain interfaces revealed different signal shapes and contrast. Good agreement between theory and experiment was found when the optical contrast at the interface is negligible. Examples are shown where the thermal barrier model is no longer valid and an extended model seems to be necessary.