🚀 go-pugleaf

In article <6220003@hpcupt1.HP.COM> dclaar@hpcupt1.HP.COM (Doug Claar) writes:
>This is probably a naive question, but how do you aim a laser beam? (I know,
>very carefully!). But seriously, are there non-mechanical methods to aim
>a beam, or must I rely on moving mirrors around? What do things like
>handheld laser barcode scanners and heads-up displays do? Are they
>mechanical??

Most laser scanners use spining mirrors and electro-mechanical shutters.
Some use electo-optical shutters, like LCDs. However, for really high
speed laser stering, the neatest trick I've heard of is an ultrasonic
diffraction grating. An ultrasonic standing wave creates a density
sine wave in air, water, or other material. By changing the frequence
of the sound, the grating spacing changes and hence the angle of
diffraction changes. Very high speed, low mass system. Of cousre,
there is the old trick of a mylar mirror on a speaker cone.
If the speed of electrical response of non-linear optical materials
ever gets high enough, electronic gratings will be a big application.

					R. Piner