Skip to content
OpticsIntroStarter track

Concept module

Polarization

Use one compact polarizer bench to see polarization as the orientation story of transverse waves, how angle mismatch sets transmitted light, and why one ideal polarizer makes unpolarized light emerge with one chosen axis.

The simulation shows a compact transverse cross-section bench with three circular stations: the input, the polarizer, and the detector. A beam-direction guide points horizontally to the right while orientation lines inside the circles show the incoming polarization, the polarizer axis, and the transmitted output. Optional overlays can call out the transverse cross-section, the axis projection, and the transmitted-versus-blocked detector split. The readout card summarizes the input state, input angle, polarizer angle, relative angle, transmitted field amplitude, and relative detector intensity. A linearly polarized input at 20° meets a polarizer at 50°, so the relative angle is 30°. The transmitted field amplitude is 0.95 arb., the blocked field is 0.55 arb., and the detector receives 0.75 of the incoming intensity.

Interactive lab

Keep the stage, graph, and immediate control feedback in one working view.

Polarization

A transverse cross-section view keeps the input orientation, polarizer axis, and detector brightness on the same compact bench.

Live setup
Live polarization benchlinear inputfiltered outputinputpolarizer axisdetectortheta_in = 20°theta_p = 50°mostly brightbeam directionoscillation orientation lives in the transverse cross-sectiondelta theta = 30°inputaxisblockeddetector fraction 0.75transmitted 75%blocked 25%Polarizer stateinputlineartheta_in20°theta_p50°delta theta30°E_out0.95 arb.I / I00.75partial projection for the current angle difference.The output orientation is reset to the polarizer axis.

Graphs

Switch graph views without breaking the live stage and time link.

Power split vs polarizer angle

Sweeps the polarizer axis to compare transmitted and blocked intensity fractions on the same response curve.

polarizer angle (°): 0 to 180relative intensity: 0 to 1
Transmitted I/I0Blocked I/I0
Power split vs polarizer angleSweeps the polarizer axis to compare transmitted and blocked intensity fractions on the same response curve.0367210814418000.250.50.751polarizer angle (°)relative intensity
Hover or scrub to link the graph back to the stage.polarizer angle (°) / relative intensity

Controls

Adjust the physical parameters and watch the motion respond.

1.1 arb.

Scales the incoming field height without changing the orientation geometry.

20°

Rotates the incoming linear polarization direction.

50°

Rotates the transmission axis of the ideal polarizer.

More tools

Secondary controls, alternate presets, and less-used toggles stay nearby without crowding the main bench.

Show

More presets

Presets

Predict -> manipulate -> observe

Keep the active prompt next to the controls so each change has an immediate visible consequence.

ObservationPrompt 1 of 1
When the input and axis line up, the detector stays bright because almost the whole transverse oscillation already points along the axis.

Try this

Start from Baseline linear, then rotate the axis until it matches the input angle.

Equation map

See each variable before you move it.

Select a symbol to highlight the matching control and the graph or overlay it most directly changes.

Input field amplitude
1.1 arb.

Changes the absolute size of the incoming and transmitted field without changing the relative transmission curve.

Graph: Power split vs polarizer angleGraph: Field projection vs polarizer angleOverlay: Detector split

Equations in play

Choose an equation to sync the active symbol, control highlight, and related graph mapping.

More tools

Detailed noticing prompts, guided overlays, and challenge tasks stay available without taking over the main bench.

Hide

What to notice

Use one prompt at a time so the orientation story stays compact and readable.

ObservationPrompt 1 of 1
Graph: Power split vs polarizer angle
When the input and axis line up, the detector stays bright because almost the whole transverse oscillation already points along the axis.

Try this

Start from Baseline linear, then rotate the axis until it matches the input angle.

Why it matters

It shows that a polarizer keeps a component; it does not invent one from nowhere.
Control: Input angleControl: Polarizer angleGraph: Power split vs polarizer angleGraph: Field projection vs polarizer angleOverlay: Projection guideOverlay: Detector split

Guided overlays

Focus one overlay at a time to see what it represents and what to notice in the live motion.

3 visible

Overlay focus

Transverse cross-section

Separates the beam direction from the sideways oscillation orientation.

What to notice

  • The beam still travels to the right while the active polarization question lives in the cross-section perpendicular to that motion.

Why it matters

It keeps polarization tied to transverse-wave geometry instead of treating it as a brightness-only effect.

Control: Input angleControl: Polarizer angleGraph: Field projection vs polarizer angleEquation

Challenge mode

Use the same compact bench for small polarization hunts instead of separate worksheets.

0/2 solved
TargetCore

2 of 4 checks

Set a half-power case

Starting from Aligned pass, tune the bench until the detector reads about one half of the incoming intensity for a linear input.
Graph-linkedGuided start2 hints

Suggested start

Use the power-split graph to steer the detector fraction toward one half.
Matched
Open the Power split vs polarizer angle graph.
Power split vs polarizer angle
Matched
Keep the Projection guide visible.
On
Pending
Set the detector fraction between 0.46 and 0.54.
0.75
Pending
Keep the relative angle between 42 deg and 48 deg.
30°

The checklist updates from the live simulation state, active graph, overlays, inspect time, and compare setup.

A linearly polarized input at 20° meets a polarizer at 50°, so the relative angle is 30°. The transmitted field amplitude is 0.95 arb., the blocked field is 0.55 arb., and the detector receives 0.75 of the incoming intensity.
Equation detailsDeeper interpretation, notes, and worked variable context.

Field projection onto the axis

The transmitted field is the component of the incoming transverse oscillation along the polarizer axis.

Input field amplitude 1.1 arb. Input orientation 20° Polarizer axis 50°

Malus's law

Detector brightness depends on the squared projection because intensity follows the square of field amplitude.

Input field amplitude 1.1 arb. Input orientation 20° Polarizer axis 50°

Crossed polarizers

If the incoming linear polarization is perpendicular to the axis, an ideal polarizer blocks it almost completely.

Input orientation 20° Polarizer axis 50°

Unpolarized first-pass average

An ideal first polarizer sends an unpolarized beam into one linearly polarized output with half the original intensity on average.

Output orientation

Whatever survives leaves aligned with the polarizer axis.

Polarizer axis 50°

Progress

Not startedMastery: NewLocal-first

Start exploring and Open Model Lab will keep this concept's progress on this browser first. Challenge mode has 2 compact tasks ready. No finished quick test, solved challenge, or completion mark is saved yet.

Let the live model runChange one real controlOpen What to notice

Try this setup

Copy the live bench state and reopen this concept with the same controls, graph, overlays, and compare context.

Stable links

Starter track

Step 1 of 50 / 5 complete

Wave Optics

Next after this: Diffraction.

1. Polarization2. Diffraction3. Double-Slit Interference4. Dispersion / Refractive Index and Color+1 more steps

This concept is the track start.

Short explanation

What the system is doing

Polarization is the compact wave-optics idea that only makes sense when the oscillation has an orientation across the beam. On this page, the beam still travels to the right, but the active question is what direction the electric-field oscillation points in the transverse cross-section.

One shared bench keeps the input orientation, the polarizer axis, the transmitted output, and the detector brightness tied to the same bounded model. That makes polarization a projection story instead of a memorized slogan: the axis keeps the component aligned with it, blocks the perpendicular part, and leaves the transmitted light polarized along the axis.

Key ideas

01Polarization is an orientation property of transverse waves, not a separate kind of intensity control.
02For linearly polarized input, the transmitted field is the projection onto the polarizer axis, so the detector fraction follows Malus's law: I_out / I_0 = cos^2(delta theta).
03For an ideal first polarizer with unpolarized input, the transmitted intensity averages to one half and the output becomes linearly polarized along the axis.
04This is why polarization distinguishes transverse-wave behavior cleanly: a longitudinal compression wave does not bring one sideways oscillation direction for a polarizer to select.

Live polarization checks

Solve the exact state on screen.

Read the current input state, axis projection, and detector fraction directly from the same live bench.
Live valuesFollowing current parameters

For the current bench state, what output leaves the polarizer and what fraction of the incoming intensity reaches the detector?

Input state

Linear input at 20°

Input angle

20° °

Polarizer angle

50° °

Relative angle

30° °

1. Read the live state

The input is Linear input at 20° and the polarizer axis is set to 50°, so the bench treats the transmission as an orientation match problem.

2. Keep only the axis-aligned part

The axis keeps only the cosine projection of the input, so the transmitted field follows the current partial projection case. That gives a transmitted field amplitude of 0.95 arb..

3. Read the detector and output axis

The detector receives 75% of the incoming intensity, and the output leaves linearly polarized along 50°.

Current transmitted output

The input is only partly aligned with the axis, so the detector reads a partial transmission and the output is reset to 50°.

Transverse-wave checkpoint

A student says, "If sound is also a wave, one ideal polarizer should just pick the right sound direction too." What is the missing ingredient in that argument?

Prediction prompt

Answer from the bench picture of transverse orientation, not from a memorized definition.

Check your reasoning

A longitudinal sound wave in air does not bring one sideways oscillation direction for the polarizer to project onto.
The bench works because the oscillation lives in the transverse cross-section and can be resolved into axis-aligned and perpendicular components. A longitudinal compression wave oscillates mainly along the propagation direction instead, so this kind of orientation filter does not apply in the same way.

Common misconception

A polarizer is just a dimmer, so any wave should pass through it the same way if the source is strong enough.

An ideal polarizer does not ask how strong the wave is first. It asks how much of the transverse oscillation points along its axis.

That is why polarization is a useful contrast with longitudinal waves such as sound in air. There is no single sideways oscillation direction there for the filter to project onto.

Quick test

Reasoning

Question 1 of 4

Answer from the live orientation logic, not from isolated vocabulary.

Why is polarization a useful signature of transverse-wave behavior?

Choose one answer to reveal feedback, then test the idea in the live system if a guided example is available.

Accessible description

The simulation shows a compact transverse cross-section bench with three circular stations: the input, the polarizer, and the detector. A beam-direction guide points horizontally to the right while orientation lines inside the circles show the incoming polarization, the polarizer axis, and the transmitted output.

Optional overlays can call out the transverse cross-section, the axis projection, and the transmitted-versus-blocked detector split. The readout card summarizes the input state, input angle, polarizer angle, relative angle, transmitted field amplitude, and relative detector intensity.

Graph summary

The power-split graph sweeps the polarizer angle and compares transmitted and blocked relative intensity. The field-projection graph sweeps the same angle and compares the axis-aligned and perpendicular field components.