Two-photon absorption-induced photoacoustic and luminescence imaging employing a femtosecond laser

We present two-photon absorption-induced photoacoustic measurements. Since two-photon photoacoustics is a nonlinear effect numerous physical effects might lead to similar observations. In the presented paper we focus on the effect of the temperature dependent Gruneisen coefficient of water. We discuss the expected theoretical behavior and compare measurements with theoretical predictions. Finally, we demonstrate multimodal photoacoustic and luminescence microscopy via two-photon absorption, and show that it is possible to image objects with localized dyes. Excitation is performed using a femtosecond laser with a wavelength of 800nm. The photoacoustic signals, the luminescence intensity and its spectrum were detected simultaneously.