Article · Wikipedia archive · Last revised Jun 6, 2026

Extinction cross

The extinction cross is an optical phenomenon that is seen when trying to extinguish a laser beam or non-planar white light using crossed polarizers. Ideally, crossed polarizers block all light, because light that is polarized along the polarization axis of the first polarizer is perpendicular to the polarization axis of the second. When the beam is not perfectly collimated, however, a characteristic fringing pattern is produced.

Last revised
Jun 6, 2026
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An extinction cross photographed with a CCD camera using a green laser beam and a polarizer source ↗

The extinction cross is an optical phenomenon that is seen when trying to extinguish a laser beam or non-planar white light using crossed polarizers. Ideally, crossed (90° rotated) polarizers block all light, because light that is polarized along the polarization axis of the first polarizer is perpendicular to the polarization axis of the second. When the beam is not perfectly collimated, however, a characteristic fringing pattern is produced.

See also

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Further reading

Further reading