Diffraction Limit Calculator

Tool Description

The diffraction limit is the theoretical upper bound of an optical system's resolution. Based on classical theories such as the Rayleigh criterion, Airy disk, and Strehl ratio, this tool calculates the limiting resolution under different wavelengths and apertures, applicable to laser focusing, imaging systems, and lithography.

Input Parameters

Wavelength λ (nm)

Entrance Pupil Diameter D (mm)

Focal Length f (mm)

Image-space Medium Refractive Index n

Results

Airy Disk Diameter (image space)

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Rayleigh Angular Resolution

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Rayleigh Linear Resolution

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f-number (f/#)

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Numerical Aperture NA

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Depth of Focus (DOF, ±)

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First Dark Ring Angular Radius

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Strehl Ratio Tolerable Wavefront Error

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Airy Disk Illustration

Central bright spot (83.8% energy)

First bright ring (7.2% energy)

Dark ring (zero intensity)

Core Formulas

Airy disk angular radius

θ = 1.22 × λ / D

Rayleigh criterion (linear distance)

δ = 1.22 × λ × f / D

Depth of Focus (half value)

DOF = ±2λ × (f/#)²

Maréchal wavefront error

σ ≤ λ / 14（Strehl ≥ 0.8）

Resources

Tool Description

Input Parameters

Results

Airy Disk Illustration

Core Formulas

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