Thin waveplate lenses of switchable focal length--new generation in optics.

We present new lenses - waveplate lenses created in liquid crystal and liquid crystal polymer materials. Using an electrically-switchable liquid-crystal half-wave retarder we realized switching between focused and defocused beams by the waveplate lens. A combination of two such lenses allowed the collimation of a laser beam as well as the change of focal length of optical system.