# Coherence Length Calculator

## About Coherence Length Calculator (Formula)

The Coherence Length Calculator is a tool used to calculate the coherence length of a wave or beam. This calculator helps determine the distance over which the wave remains coherent, or in-phase, before significant phase changes occur.

The formula for calculating the coherence length depends on the specific characteristics of the wave or beam being considered. For a monochromatic wave or laser beam with a narrow frequency bandwidth, the coherence length (L) can be approximated using the formula:

L = λ^2 / Δλ

Where: L = Coherence length λ = Wavelength of the wave or beam Δλ = Bandwidth or range of frequencies within the wave or beam

To use this formula, you need to know the wavelength of the wave or beam and the bandwidth or frequency range. By squaring the wavelength and dividing it by the bandwidth, you can estimate the coherence length.

It’s important to note that the coherence length represents the distance over which the wave remains coherent within a specified tolerance level, usually around 90% or 95%. The coherence length is influenced by factors such as the spectral properties of the wave or beam, temporal and spatial coherence, and environmental conditions.

When using the Coherence Length Calculator, ensure accurate measurement or knowledge of the wavelength and bandwidth to obtain reliable results. Additionally, consider any specific adjustments or corrections needed for different types of waves or beams, as well as the coherence requirements of the particular application or experiment.

By applying the coherence length formula correctly, you can estimate the distance over which a wave or beam remains coherent, providing insights into its coherence properties and aiding in various fields such as optics, interferometry, and laser applications.