Diffraction Limit Calculator

What is the Diffraction Limit?

The diffraction limit, also known as the Rayleigh criterion, describes the limit of resolution of a microscope or other imaging system. It determines the smallest distance between two points that can be resolved as separate entities.

How to Use This Calculator

1. Enter the wavelength of light (λ) in meters. Common values include:
• Visible light: ~0.0004 to 0.0007 meters
• Red light: ~0.0006328 meters
• Green light: ~0.0005 meters
• Blue light: ~0.00047 meters
2. Enter the aperture diameter (D) of your optical system in meters. This is typically the diameter of the lens or opening.
3. Click the "Calculate" button to compute the diffraction limit.
4. The result will be displayed in radians and approximately in meters at f=1.

Principle Explanation

The diffraction limit is determined by the wave nature of light. When light passes through an aperture, it diffracts and forms a pattern of waves that spread out. The mathematical relationship is given by the formula:

θ = 1.22 × (λ / D)

Where θ is the diffraction limit (half-angle in radians), λ is the wavelength of light, and D is the aperture diameter.

Applications

This calculator is useful for:

• Optical engineers designing microscopes and telescopes
• Physicists working with optical systems
• Researchers determining the resolution limits of imaging equipment
• Anyone interested in understanding the fundamental limits of optical resolution