Abstract: An infrared collector which employs a non-directive concentrator to concentrate the infrared radiation received in the collector on a detector. In a preferred embodiment, the concentrator is a plastic hemisphere which has an array of PIN diodes glued to its flat side. The hemisphere may have any radius which is greater than or equal to a value dN, where N is the index of refraction of the plastic making up the hemisphere is N and d is the distance from the center of the array of diodes to the most remote part of the infrared-sensitive material. The fact that the concentrator is non-directive obviates the need to aim receivers employing the concentrator at transmitters. The receivers and transmitters need only be in line of sight of each other. The concentrator may further be used generally to concentrate infrared and visible radiation.