A gas-lens telescope

• Published in: Nature (London) 1991-10, Vol.353 (6344), p.547-548
• Main Authors: Kosch, M, Michaelis, M. M, Notcutt, M, Cunningham, P. F, Waltham, J. A, Prause, A, Dempers, C. A
• Format: Article
• Language: English
• Subjects: Astronomical and space-research instrumentation; Astronomy; Earth, ocean, space; Exact sciences and technology; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Humanities and Social Sciences; letter; multidisciplinary; Science; Science (multidisciplinary); Telescopes
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/353547a0

A GAS lens is capable of focusing light if the temperature, and therefore refractive index, of a gas is made to vary across an optical aperture in a suitable manner. Practical applications of gas lenses were pursued thirty years ago 1,2 in the context of power transmission by laser beams, but little work has been done since then. It was recently shown, however, that a gas lens can focus a laser beam well enough to drill holes in a metal sheet 3 , and it has been argued 4 that gas lenses are 'varifocal' devices with negligible dispersion from ultraviolet to infrared wavelengths, and that they may be able to transmit and focus more powerful laser beams than conventional lenses can cope with. They may therefore find some application in laser-driven thermonuclear experiments 5 . Here we describe another application of gas lenses: telescopy. We have constructed a simple gas lens telescope, and have used it to make images of the Sun and the Moon.