title: Determination of the longitudinal profile of a focused Nd:YAG Gaussian beam from second-harmonic generation in a thin KTP crystal.
abstract: We present an original experiment describing a focused Gaussian laser beam by using second-harmonic generation (SHG) in a thin strip of a nonlinear optical material, in this case KTP doubling of an Nd:YAG laser at 1.064 µm. The dependence of the SHG efficiency on the fundamental beam radius allows the determination of beam parameters by harmonic-power measurements. The characterization of a telescope shows the good precision of this method in radii in the range of 10-100 µm. The average accuracy is 4% for the radius determination and 1.5% for the beam-waist localization.
authors.forename: J P
authors.initials: JP
authors.lastname: Fève
authors.forename: B
authors.initials: B
authors.lastname: Boulanger
authors.forename: G
authors.initials: G
authors.lastname: Marnier