Transmission Gratings - Physics Demonstrations - Transmission Gratings | Physics Undergraduate Labs

Never look directly into the laser beam or view specular reflections. Class 3R lasers (>1 mW but <5 mW) require additional precautions: post warning signs, use a beam stop, and prevent eye exposure. Ensure the laser is mounted securely and cannot be accidentally redirected toward the audience. The reflection shield helps contain stray reflections from the optical rail.

Purpose

Demonstrates how grating line density affects angular separation of diffraction orders. Comparing 100, 300, and 600 lines/mm gratings with a laser, students directly observe that higher line density (smaller $$d$$ ) produces wider angular spread, verifying $d \sin\theta = m\lambda$ .

$Three PASCO Scientific transmission diffraction gratings in metal slide mounts, labeled 100 LINES/MM, 300 LINES/MM, and 600 LINES/MM, on a green surface$

Figure 1: PASCO transmission gratings (100, 300, and 600 lines/mm) in slide mounts for use with the optical rail.

Safety Warnings

Warning: Laser Safety - Class 2 or 3R Lasers

Purpose