Üdvözöljük a fotoakusztika oldalain

In climate research aerosols are classified into different components, having largely different effects on global climate, air quality and human health. Even more, aerosols classified into the same group but originated from different sources may also possess similar diversified effect. Therefore it is highly important to measure aerosols selectively. On the other hand such a measurement is very challenging too. The wavelength dependence of the optical absorption of aerosols might be a base for this differentiation. For this purpose a multi-wavelength photoacoustic (PA) system was developed based on a diode-laser pumped, high repetition frequency, Q-switched Nd:YAG laser and its nonlinear wavelength conversions. Wavelength conversions are achieved by focusing the near-infrared light first to a nonlinear LBO crystal and after to second nonlinear CLBO crystal. With this optical solution three different wavelengths were achieved, namely 1064 nm, 532 nm and 266 nm. The distances (in spectroscopic aspect) among them – according to the aim – are sufficient to distinguish the different type of aerosols, as well as the rate contribution of different sources to the total atmospheric aerosol load. In other words, our system has the potential to make difference between soot arises from traffic and from domestic wood burning. To fulfill the requirements of field application the whole part of our system was build in a compact and portable box.