Procedures for the measurement of the extinction cross section of one particle using a Gaussian beam

•We compare two procedures for measuring the extinction cross section of particles using Gaussian beams.•Procedures are based in the optical theorem and a direct measurement of extinction.•Accuracy and limitations of the procedures are determined using Mie theory.

Two procedures for the measurement of the extinction cross section (ECS) of one particle using a slightly focused Gaussian beam have been introduced and numerically tested. While the first one relies on previously introduced ideas and has close connection with the optical theorem, the second procedure is new and is mostly related with light measurements where the detector collects much of the energy of the incident beam.Both procedures prove to be valid and somehow complementary up to particle sizes of the order of the beam waist, thus enlarging the capability of simple measurement set-ups based on Gaussian beams for the estimation of the ECS of one particle.