Gaussian Beam Rayleigh Range Calculator

Apply the paraxial fundamental Gaussian-beam relation to the waist radius. Do not substitute diameter for radius; doing so changes range by a factor of four. It evaluates only the displayed equation and entered SI values; it does not infer material data or experimental conditions. Confirm the convention and inputs against the physical setup before using the result.

At one Rayleigh range from the waist, ideal beam radius is square root of two times its waist value. Larger waist radius increases range quadratically while longer wavelength reduces it. Display precision is not measurement accuracy. Check dimensions, scale, limiting cases, and input uncertainty against an independent source before using the value in laboratory, engineering, or safety-sensitive work.

The beam is an ideal paraxial TEM00 Gaussian beam and waist radius uses the one-over-e-squared intensity convention. Beam quality above one, astigmatism, truncation, lenses, media index, aberration, and nonparaxial focusing are excluded. This educational result is not a simulation, calibration, design approval, or safety determination. Real systems may require measured properties, geometry, boundary conditions, uncertainty propagation, and numerical models beyond these inputs.