Photoacoustic and nephelometric spectroscopy of aerosol optical properties with a supercontinuum light source
- 1Atmospheric Science Program and Physics Department Michigan Technological University, 1400 Townsend Drive Houghton MI, 49931, USA
- 2Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Pkwy Reno, NV 89512, USA
- 3Physics Department, University of Nevada, 1664 N Virginia St Reno, NV 89557, USA
Abstract. A novel multi-wavelength photoacoustic-nephelometer spectrometer (SC-PNS) has been developed for the optical characterization of atmospheric aerosol particles. This instrument integrates a white light supercontinuum laser with photoacoustic and nephelometric spectroscopy to measure aerosol absorption and scattering coefficients at five wavelength bands (centered at 417, 475, 542, 607, and 675 nm). These wavelength bands are selected from the continuous spectrum of the laser (ranging from 400–2200 nm) using a set of optical interference filters. Absorption and scattering measurements on laboratory-generated aerosol samples were performed sequentially at each wavelength band.
To test the instrument we measured the wavelength dependence of absorption and scattering coefficients of kerosene soot and common salt aerosols. Results were favorably compared to those obtained with a commercial 3-wavelength photoacoustic and nephelometer instrument demonstrating the utility of the SC light source for studies of aerosol optical properties at selected wavelengths. Here, we discuss instrument design, development, calibration, performance and experimental results.