Abstract: A method and apparatus for producing high intensity electromagnetic radiation are disclosed. The apparatus includes a high intensity arc lamp having an inner envelope cooled by a first flow of liquid along an inside surface of the inner envelope. The arc lamp includes first and second electrodes for generating a high power plasma arc within the inner envelope, the arc emitting the radiation. The apparatus further includes a cooling device for producing a second flow of liquid in contact with an outside surface of the inner envelope. In order to approximate a desired electromagnetic radiation spectrum, the apparatus may further include an energy redistributor for redistributing energy within a first radiation spectrum generated by the arc to produce a second radiation spectrum.