Atomic EIT quantum memory
A 34-second sectional explainer of electromagnetically induced transparency storage in an atomic ensemble. 1,020 frames, 30 fps, indexed 0-1019. Category: quantum communication.
Reduced motion. Playback starts paused on the closing view. Press Play if you want the camera moves.
Safeguards and accuracy boundaries
- This is an explanatory schematic, not a certified physics reference, a laboratory procedure, or a laser-safety guide. Do not build, align, or operate hardware from this plate.
- Cyan, gold, and violet mark the signal pathway, the control field, and collective coherence. They are not emission colors and not photon sprites.
- The drawing does not show a stationary glowing photon, a copied pulse, perfect retrieval, or indefinite storage.
- Inside the ensemble the signal envelope's group velocity is reduced. The vacuum speed of light is not changed. Optical carrier cycles are omitted on purpose.
- Slow motion, time compression, and scale changes are labeled on the plate. No storage time, efficiency, optical depth, or Rabi frequency is claimed as a measurement.
- The mixing ratio is chosen so the spatial compression is visible. It is not a fitted device parameter.
- Atom number and spacing are diagrammatic. A laboratory ensemble is far denser.
- The control-field angle is exaggerated so the two beams can be distinguished.
- Nothing here collects personal data, and nothing autoplays with sound.
What the five sections show
- Frames 0-149. The ensemble cell, in longitudinal section, and the signal and control paths.
- Frames 150-299. The lambda system: signal on |g> to |e>, control on |s> to |e>, and the two-photon coherence. The cell stays in frame.
- Frames 300-509. The incoming envelope shortens in space as its group velocity drops inside the medium.
- Frames 510-749. Lowering the control maps that polariton onto a collective spin wave. The same excitation stops propagating. It is not copied into a second pulse.
- Frames 750-1019. Restoring the control maps the spin wave back to the forward mode. The outgoing envelope is weaker. The last second holds a still, complete view.
Model, not a measurement
The ideal dark-state polariton used on the plate is the Fleischhauer and Lukin relation: the mixing angle satisfies cos theta = Omega_c / sqrt(Omega_c^2 + g^2 N), and the envelope group velocity is vg = c cos^2 theta. Further laboratory demonstrations of storage and retrieval include Liu, Dutton, Behroozi, and Hau, Nature 409, 490 (2001), and Phillips, Fleischhauer, Mair, Walsworth, and Lukin, Physical Review Letters 86, 783 (2001). Those papers are context, not a claim that this animation reproduces their apparatus or their numbers.
Keyboard: Space plays or pauses. Arrow keys step 15 frames. Shift plus an arrow steps one frame. Home and End jump to the ends.