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Pockella
The Pockels Effect / Δn ∝ E Physics
Pockella, a grey-haired crystal-tamer, holds a glowing crystal between two electrodes with a beam passing through.
The Physics
Some crystals without a centre of symmetry change their refractive index in direct proportion to an applied electric field. Friedrich Pockels studied this linear electro-optic effect in 1893. Put such a crystal between crossed polarisers and a voltage can switch light on and off in nanoseconds.
Δn ∝ E
- Δn: change in refractive index
- E: applied electric field (V/m)
Pockels cells Q-switch lasers and modulate signals in optical communications.
Honest caveat: Only non-centrosymmetric crystals show it; others show the weaker Kerr effect, Δn ∝ E². The exact coefficient depends on crystal axes.
On the sticker
Pockella holds a glowing cube crystal between two plates with a cyan beam running through it. Printed text: POCKELLA with the line Δn ∝ E. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.
Shipping calculated at checkout by destinationMade to order, ships in 2–5 business days
Details
Size3″ × 3″
3″ × 3″ kiss-cut sticker.
Shipping
Shipping calculated at checkout by destination. Printed to order for you.
Returns & replacements21 days
Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.
Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.
Field notes
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