Abstract

In a number of long-path optical devices related basically to highly-sensitive absorption spectroscopy and optical delay lines, laser sources and specially designed White-type¹ multireflection cells have been used. The basic disadvantage of such guiding systems is that they are designed by using heavy curved-surface mirrors and based on ray-optics approximation. Hence, such systems are highly sensitive to beam divergence and any kind of mirror surface roughness. A new approach proposed in this paper is based on wave optics, i.e., optics of 2-D limited plane waves or on Lommel² optics. Then the guiding system contains only a composition of flat mirror surfaces so that the final device can be light and portable still preserving very long optical paths (up to 100 m, within portable sizes). Moreover, such a system is beam-divergence/mirror-surface-roughness weakly sensitive; hence conventional sources such as LEDs, halogen lamps, etc. can be used, significantly decreasing the cost of the system. Additionally, for concentrating/collimating of the conventional source light beam, Winston’s nonimaging optics³ is used, highly improving sensitivity and optical S/N of the system.

© 1985 Optical Society of America