An interface between two different optical materials can comprise a stack of thin film layers that manage light incident on that interface. Multiple collimators are used to successively trim the radiation beam to match the detector plate while simultaneously eliminating scatter from the previous stages. The main body portion and the distal end portion are insertable through a vein that is fluidly connected with the coronary vein and into the coronary vein. The bag may also include a front wall, a back wall, and a hem, the hem including a drawstring. A further bipolar transistor is formed according to the following method of the invention.