Calcite Crystals - Physics Demonstrations - Calcite Crystals | Physics Undergraduate Labs

Use Class 2 lasers (<1 mW) when possible for lecture demonstrations. For Class 3R lasers (1-5 mW), ensure beam terminates on a screen and avoid reflective surfaces. Never allow direct eye exposure or reflections into the audience.

Purpose

Demonstrates birefringence (double refraction) in calcite crystals. A laser beam splits into two orthogonally polarized rays (ordinary and extraordinary), showing that the refractive index depends on polarization direction.

$Calcite crystal sitting on a textbook page showing "Chapter 43 Polarization," with text visible through the crystal shifted by double refraction$

Calcite crystal on a metal platform with green laser beam entering from below, producing two bright green spots on the wall behind

Figure 1: Calcite crystal on a textbook page — text viewed through the crystal is displaced by double refraction.

Figure 2: Green laser split into ordinary and extraordinary beams by the calcite crystal, producing two separated spots on the wall.

Safety Warnings

Warning: Laser Safety

Purpose