Making a glass Fresnel lens with its concentric ... we are guessing that half the light is diffracted outwards rather than inwards by the cylindrical profile of the coil, but for the cost of ...

The Fresnel lighthouse lens used a large lamp at the focal plane as its light source. It also contained a central panel of magnifying glasses surrounded above and below by concentric rings of ...

the ones on the edges bending light more sharply and the center bending it hardly at all. Compared to a conventional lens, a Fresnel will be thinner and lighter or — conversely — for the same ...

Engineers and astronomers at the University of Utah have designed a unique new kind of telescope lens: a flat lens with microscopic etchings to refract light ... called a Fresnel zone plate ...