No-loss bent light pipe with an equiangular spiral

Bending a light pipe and maintaining the required volume and size, while at the same time preserving source energy and minimizing bend losses, is the basic criterion for designing a light pipe. An important requirement is the design of a light pipe that is capable of being bent without loss of light and with no limitations on acceptance angle. It is shown that in theory such a light pipe does exist, in a form corresponding to the so-called golden rectangle. Numerical simulations with six different no-loss light pipes with multiple bends are provided as a demonstration.