The formula to calculate the Rayleigh Length (Zr) is:
\[ Zr = \frac{\pi \cdot w^2}{\lambda} \]
Where:
The Rayleigh Length is the distance along the propagation direction of a beam from the beam waist to the place where the area of the cross-section is doubled. It is a measure of how quickly a beam diverges.
Let's assume the following values:
Using the formula:
\[ Zr = \frac{\pi \cdot 1^2}{0.5} \approx 6.28 \text{ mm} \]
The Rayleigh Length (Zr) is approximately 6.28 mm.