A device for conversion of an optical radiation flux, the device having a plurality of channels for receiving and transmitting optical flux and the channels having input 6 and output 8 end faces. Radiation, such as light, may be transported with or without reflections from the interior walls of the channels, depending upon curvature or lack thereof. Radiation diverging from a point source can be focused by the device to form large or small images following the output of the device along a longitudinal axis thereof. The input and output faces of the device can be used in reverse fashion. Radiation passing through the device will continue along a directed path in accordance with axial extensions, or continuations, of the individual channel axis.