1. What is Gaussian Beam Divergence?

Gaussian beam divergence describes the angular spread of a laser beam as it propagates. It's a fundamental property of laser beams that determines how quickly the beam expands with distance.

2. How Does the Calculator Work?

The calculator uses the Gaussian beam divergence equation:

Where:

• \( \theta \) — Beam divergence angle (radians)
• \( \lambda \) — Wavelength of the laser light (meters)
• \( w_0 \) — Beam waist radius (meters)

Explanation: The equation shows that divergence is directly proportional to wavelength and inversely proportional to the beam waist size.

3. Importance of Beam Divergence Calculation

Details: Understanding beam divergence is crucial for laser system design, optical communications, laser cutting applications, and any scenario where beam size at a distance matters.

4. Using the Calculator

Tips: Enter wavelength and beam waist in meters. Both values must be positive numbers. For typical laser diodes, wavelength might be in nanometers (e.g., 635nm = 635e-9m).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between full angle and half-angle divergence?
A: This calculator gives the half-angle divergence. Full angle divergence would be 2θ.

Q2: How does divergence affect beam diameter at distance?
A: Beam diameter ≈ 2w₀ + 2θ×distance (for small angles).

Q3: What's a typical beam divergence value?
A: For a HeNe laser (632.8nm) with 0.5mm waist: ~0.4mrad. Laser diodes often have 5-30mrad divergence.

Q4: Can this be used for non-Gaussian beams?
A: No, this applies only to fundamental TEM₀₀ Gaussian beams. Multimode beams have different divergence characteristics.

Q5: How can I reduce beam divergence?
A: Increase beam waist (w₀) using a beam expander, or use a shorter wavelength laser.