A photoacoustic spectrometer for the measurement of aerosol absorption spectra, based on the excitation of a pulsed nanosecond optical parametrical oscillator (OPO), has been demonstrated . This spectrometer is working at ambient pressure and can be used to detect and characterize different classes of aerosols. The spectrometer features a spectral range of 410 nm to 2500 nm and a sensitivity of 2.5 × 10⁻⁷ m⁻¹ at 550 nm. As we demonstrate, it is possible to determine a specific optical absorption per particle by a combination of the new spectrometer with an aerosol particle counter.

Currently, we develop another pulsed PA system, based on a single, high-repetition laser, emitting three different wavelengths (1064 nm, 532 nm, 366 nm). Possible applications can be environmental as well as process anlytical challenges.