… And it Comes Out Here

Giving Light a Spin

Ordinary, unpolarized light can be thought of as an equal mixture of clockwise- and counterclockwise-rotating, circularly polarized waves. To create pure, circularly polarized light, a filter can absorb one polarization state and let the other pass through. Such filters are not hard to make, but they are inefficient, since half of the initial light is lost. Liquid crystals are known to emit circularly polarized light, and light from certain semiconductors can become polarized when a magnetic field is used [1]. But these systems are rather large and inflexible in their design.

True, but this ignores lasers which emit linearly polarized light, which can be circularly polarized with a quarter-wave retarder. But there are probably advantages to having it all as a monolithic compact system.

(I also wonder what will happen when someone notices that this system uses a swastika shape, which from a technology standpoint is not particularly surprising — you need a chiral shape, and straight lines are generally the easiest to etch (it has to be a pattern supported by the crystal structure of the material). But given the conservapedia invent-a-furor over relativity, who knows what will happen in the blogohedron?)

2 thoughts on “… And it Comes Out Here

  1. It’s OK – they have the opposite chirality of the political symbol. Consider the English. SOP for a past enemy was to do some POW digital deletion so a recovered longbowman could not draw. That begat the graphic insult of the first two fingers displayed with palm toward the displayer. Churchill did a vertical axis 180 degree rotation into a “V” for victory.

  2. It’s true the word swastika itself originates in sanskrit. It’s been used as a symbol of well being and a religious symbol for Hinduism, Buddhism, Jainism long before any German-Nazi influence. Archeological science dates the symbol back to to atleast 5000 B.C. . Also an interesting quote I found on Wikipedia : “Life’s Other Secret (1999), Ian Stewart suggests the ubiquitous swastika pattern arises when parallel waves of neural activity sweep across the visual cortex during states of altered consciousness, producing a swirling swastika-like image, due to the way quadrants in the field of vision are mapped to opposite areas in the brain.”
    All completely unrelated to the polarization of light but still interesting.

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