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Gaussian Laser Beam Waist & Rayleigh Range Calculator

Diffraction prevents laser beams from remaining perfectly collimated over infinite distances.

Laser emission wavelength.

1/e² intensity beam radius at focal focus.

Distance from beam waist along optical axis.

Calculated Result
1046.3 µm

Beam Radius at Distance z

Rayleigh Range (z_R)

0.369 m

Full Divergence Angle (2θ)

1.35 mrad

Beam Diameter at z

2.09 mm

Calculation Breakdown

  1. Rayleigh Rangez_R = π·w₀² / λ = π·(250e-6)² / 532e-9 = 0.369 m
  2. Spot Radius at zw(z) = w₀·√(1 + (z/z_R)²) = 250·√(1 + (1.5/0.369)²) = 1046.3 µm

What Is the Gaussian Laser Beam Waist & Rayleigh Range Calculator?

Gaussian beam optics describes the spatial profile and propagation characteristics of focused and collimated laser beams.

How Does the Gaussian Laser Beam Waist & Rayleigh Range Calculator Work?

Calculates the confocal parameter and hyperbolic expansion radius from the diffraction wave equation.

Gaussian Laser Beam Waist & Rayleigh Range Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

z_R = rac{pi w_0^2}{lambda}, quad heta = rac{lambda}{pi w_0}, quad w(z) = w_0 sqrt{1 + left( rac{z}{z_R} ight)^2}

Rayleigh collimation range and beam radius hyperbolic profile.

How to Use the Gaussian Laser Beam Waist & Rayleigh Range Calculator

  1. Enter laser wavelength, focused waist radius w0, and distance z from the waist.

Step-by-Step Example Calculation

Green DPSS Laser Collimation

Input Values:

wavelengthNm:532
beamWaistRadiusUm:250
propagationDistanceM:1.5
Worked Steps: Yields Rayleigh range z_R = 0.369 m, divergence 1.35 mrad, and beam radius 1.045 mm at 1.5 m.

Understanding Your Result

Rayleigh range marks distance where beam area doubles; spot radius gives 1/e² intensity radius at target z.

Factors That Affect the Result

  • Beam quality factor M² increases real-world divergence over the ideal diffraction limit.

When Should You Use This Calculator?

  • Laser cutting nozzle focus design, optical bench alignment, lidar sensor range calculation, and fiber coupling.

Assumptions & Limitations

  • Assumes ideal diffraction-limited fundamental TEM00 mode with M² = 1.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Standard paraxial Gaussian beam formulation.

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