Fig. 1: Schematic diagram for vibrational sum frequency (VSFS) and hyper-Raman scattering (HRS) experiments.
From: In situ analysis of the bulk and surface chemical compositions of organic aerosol particles
a Schematic diagram of both the VSFS and HRS experiments. A spectrally narrow picosecond 1025 nm from an etalon was combined with a broadband OPA-generated IR femtosecond pulse at the aerosol samples to yield sum-frequency and hyper-Raman signals. L1: 1” achromatic lens of a 25 cm focal length. L2: 1” CaF2 lens of a 15 cm focal length; L3/L5: 2” achromatic lens of a 3.2 cm focal length, and L4/L6: 2” achromatic lens of a 7.5 cm focal length. b The narrow picosecond 1025 nm and the broadband IR light were non-collinearly incident on samples at angle of Ω1025 = 0° and ΩIR = 5° with respect to the X axis. The incident plane and scattering plane were in the X-Y plane, with the Z axis perpendicular to the optical table.
