Square Aperture Mask

Details

9BB200 - Passive Optical Components

Demo use only

Instances

G2B20A - Demo West (Duane Physics)

Good - Normal Wear Demo use only

Used in these demonstrations

Three overlapping projected color squares — red, green, and blue — on a dark background, with yellow, magenta, and cyan visible at pairwise overlaps and near-white in the central region where all three combine

Color Filters

Three overhead projectors with red, green, and blue filters produce overlapping colored squares, demonstrating additive color mixing. Students see secondary colors at pairwise overlaps and white where all three combine.

Desk tape dispenser viewed between crossed polarizers showing rainbow stress patterns in blue, green, yellow, and pink around the curved body and tape roll

Effects with Cellophane

Everyday transparent plastic objects placed between crossed polarizers reveal colorful stress and birefringence patterns. Demonstrates photoelasticity — how manufacturing stresses and molecular alignment produce optical anisotropy visible through polarized light.

Overhead projector stage with LC pixel assembly: film canister battery holder (left) connected by wires to the LC cell sandwiched between polarizing filters on the projector stage

Liquid Crystal Pixel

Demonstrates how an applied electric field reorients liquid crystal molecules, switching their birefringence on and off between crossed polarizers. Connects molecular-level physics directly to LCD display technology — every pixel …

Overhead view of Cenco overhead projector with crossed polarizers and magnifying lens on stage, four clear photoelastic shapes (rod, two right-angle pieces, hook) beside it

Photoelastic Models

Demonstrates stress-induced birefringence (photoelasticity). Transparent plastic shapes placed between crossed polarizers reveal colorful stress patterns when loaded, showing how engineers visualize internal strain distributions using polarized light.

Iris flower image viewed through crossed polarizers showing vivid purple, pink, and green interference colors on black background

Polarized Images

Birefringent image plates placed between crossed polarizers on an overhead projector display vivid interference colors that change dramatically when the analyzer is rotated. Demonstrates polarization, birefringence, and wavelength-dependent interference in …

Three dichroic filters in clear slide mounts resting on cloth pouches. Each filter shows two colors: blue/yellow, orange/cyan, and green/magenta (reflected above, transmitted below).

Thin Film Reflection and Transmission

Demonstrates thin-film interference using dichroic filters that selectively reflect and transmit complementary colors. Individual filters reflect primary colors and transmit secondaries; combined filters reverse this, and all three together act …

Reserve This Equipment

Demo use only

This equipment supports lecture demonstrations and cannot be reserved directly — it is assigned automatically as part of a demonstration. To use it, request a demo that includes it.