The spectral propagation equation of flat-topped beams propagating through atmospheric turbulence is derived by using the quadratic approximation of the Rytov s phase structure function.

The coherent combination of multi-Hermite-Gaussian beams is proposed to describe the flat-topped beams.

Theory of surface thermal lens signal in optical coating with cw modulated top-hat beam excitation;

Propagation of flat-topped light beams passing through ABCD optical systems;

Making use of the new model of falt-topped light beams proposed by Li recently,the analytical expressions of the M~2-factor and the field distribution of flat-topped light beams passing through a paraxial ABCD optical system have been derived,respectively.

A new synthesis method for synthesizing on-axis flat-topped beams by using a defocusing telescope system;

A new method for synthesizing on-axis flat-topped beams by using a defocusing telescope system is proposed, where the flat-topped multi-Gaussian beam is chosen as the ideal beam.

Focal shifts of flattened Gaussian beams passing through an aperture lens;

The simulation algorithm of flattened Gaussian beams(FGBs) passing through hard-aperture optics is improved,and an approximate closed-form propagation equation is derived,where a product of Fourier series and complex Gaussian function expansion is adapted to the window function of a hard-edged aperture.

The theoretical conversion efficiency of the second harmonic generation of the flattened Gaussian beam s and Gaussian beams was obtained by using the numerical simulation on the crystal CsLiB6O10 in the phase matching type I and type II for the first time.