Experiment 04 · Setup Diagram

He–Ne LASER Beam Divergence

There is nothing to wire here. The whole experiment is a LASER, a rail and two screens, and the only thing that matters is where you put them.

Procedure

1. 1.

   Switch ON the LASER.

2. 2.

   Place the two screens at a suitable distance apart.

3. 3.

   Note the distance between the two screens as D.

4. 4.

   Measure the diameter of the LASER spot on screen 1 and screen 2 as w₁ and w₂ respectively.

5. 5.

   Record the values of D, w₁, and w₂ in the observation table.

6. 6.

   Calculate the angular divergence using the formula:

   θ = √(w₂² − w₁²) / D radian

7. 7.

   Convert the angular divergence into degrees and minutes using the relations:

   1 radian = 57.3° ; 1° = 60′

8. 8.

   Repeat the experiment for two more values of D.

9. 9.

   Calculate the average value of angular divergence.