What is the Directionality of LASER?

Directionality: Laser emits light which is highly directional. Laser light is emitted like a relatively narrow beam in an exact direction. Ordinary light as like coming through the sun, a light bulb or a candle, is emitted in several directions away through the source.

The degree of directionality is expressed into terms of divergence. The divergence tells how quickly the beam spreads while this is emitted through the laser.

The angle of divergence can be expressed into degrees as given below:

Φ = (a₂- a₁) / 2(d₂- d₁),

Here d₁and d₂ are the distances through the laser window to the two spots and a₁ and a₂ are the diameter of the spots.