Photothermal Deflection Spectroscopy of Collected Aerosols

Photothermal Detection: ComparisonContinuous Excitation: Homogeneous Sample– Very sensitive non-aqueous– Convection & flow noise– Requires laser source– Signal loss with flow Solid Sample orHeterogeneous Geometry– Can use regular light sources– Good fluid heat transfer– May reduce convectionPulsed Excitation: Homogeneous Sample– Most sensitive for gases– Nonlinear effects common– Requires laser source– Best for flowing samples Solid Sample orHeterogeneous Geometry– Highest temperature change– Sample damage– Nonlinear effects– Use laser sources