Light sources
Pick the source tool (S), choose the kind of source in the inspector, then click in the view. A scene can hold up to 24 sources.
Kinds of source
Section titled “Kinds of source”Point. An oscillating current at one spot. It radiates circular waves in every direction. Good for seeing how a structure responds to light coming from everywhere, or as a small emitter inside a cavity.
Plane wave. A flat wavefront that enters from one edge and travels across the whole domain. It is injected through a total-field / scattered-field line: on the far side of the line there is the incoming wave plus whatever your geometry scatters; on the near side there is only the scattered light. So reflections show up cleanly, without the incoming wave in the way. The edge you click nearest to decides the direction. Injecting light explains how it works.
Gaussian beam. The same one-way injection with a Gaussian profile across the line. Waist radius is the 1/e half-width of the field at the line. A narrow waist spreads quickly; a wide one stays parallel for longer.
Phased array. A row of point emitters with a fixed spacing. Each one is delayed a little relative to its neighbour, which tilts the combined wavefront. Steering sets the angle. Because the delays are true time delays, steering also works for pulses. With a spacing above half a wavelength you will see extra beams (grating lobes) appear.
Waveforms
Section titled “Waveforms”| Waveform | What it does | Use it for |
|---|---|---|
| Continuous | A sine that ramps up smoothly over three periods, then runs forever. | Steady-state patterns: interference, focusing, guiding. |
| Pulse | A Ricker wavelet: one short burst centred on the chosen wavelength, with no DC offset. | Seeing reflections and delays one at a time, and broadband spectra. |
| Wave packet | About six cycles of the chosen wavelength under a Gaussian envelope. | Narrower spectra than a pulse; group velocity in waveguides. |
Pulses and wave packets fire once. Select the source and press Fire to send another.
Settings
Section titled “Settings”- Wavelength is the vacuum wavelength in nanometres. The small swatch next to it shows roughly what colour that would be; outside 380–780 nm it turns grey.
- Amplitude scales the source. The display adjusts its exposure automatically, so this mainly matters when several sources interfere.
- Phase (point sources, continuous waves) shifts the oscillation. Two point sources 180° apart give a dark line between them instead of a bright one.
- Position values are in nanometres from the top-left corner. You can also drag sources with the select tool.
Scrub any numeric field by dragging its label left or right; hold Shift for fine steps. Arrow keys in a field step by one unit, with Shift by ten.