Coherence Length Calculator

This calculator can be used to determine the coherence length of light based on its spectral width. Coherence length is an important parameter in optics that describes the distance over which light remains coherent.

Input Parameters

Calculation Results

Calculation Formula

Coherence Length (λc) = 7.96 * λ0 / Δλ

Where:
λc = Coherence Length (in meters)
λ0 = Central Wavelength (in meters)
Δλ = Spectral Width (in meters)

Coherence Length Calculator Calculator Usage Guide

Learn how to use the Coherence Length Calculator and its working principles

How to Use the Calculator

  1. Enter the spectral width (Δλ) of the light source in nanometers (nm). This is the range of wavelengths in the light source's spectrum.
  2. Click the "Calculate" button to compute the coherence length.
  3. The calculator assumes a central wavelength of 500 nm for the calculation. If you need to use a different central wavelength, you can modify the JavaScript code accordingly.
  4. The result is displayed in meters, showing how far the light maintains its phase relationship.

Working Principle

The coherence length (λc) of light is a measure of the distance over which the light wave maintains a consistent phase relationship. It is inversely proportional to the spectral width of the light source:

λc = (2π/Δν)c = (7.96/Δλ)c

where:

  • λc is the coherence length
  • Δν is the frequency bandwidth
  • Δλ is the wavelength bandwidth
  • c is the speed of light

This calculator uses the simplified formula λc = 7.96 * λ₀ / Δλ, where λ₀ is the central wavelength of the light source.

Applications

Coherence length is an important parameter in various optical applications, including:

  • Interferometry
  • Optical communications
  • Laser technology
  • Coherent detection systems