Transmission of a Gaussian scanning beam through circular, square, and slit apertures: Part I. Theory.

Energy and power values for Gaussian profile scanning laser beams through circular, square, and slit apertures may be required for hazard analysis in laser safety programs. Equations describing the transmitted power for a Gaussian beam concentric and eccentric with circular, square, and slit apertures are given. Simple expressions of transmitted power and energy with a scanning laser beam across the square and slit apertures are derived. For the circular aperture, the transmitted power and energy can be calculated conveniently by using the correction factors from the graphic values or from the computer programs.