Patent ID: 8579951

Claim:
An apparatus for treating biological tissue, comprising: a base unit, the base unit comprising an energy supply; a handpiece; an umbilicus having a first end configured to be coupled to the base unit and a second end configured to be coupled to the handpiece; a source of electromagnetic radiation, the source of electromagnetic radiation configured to receive energy from the energy supply and generate electromagnetic radiation; a waveguide configured to receive the electromagnetic radiation from the source, the waveguide comprising: first and second ends and a wall extending at least partially therebetween, the wall configured to transmit the electromagnetic radiation therethrough; a passage extending along a direction between said first and second ends; a fluorescent substance flowable within the passage; and an inlet and an outlet in fluid communication with the passage; an optical output element optically coupled to one of the first and second ends of the waveguide, wherein the fluorescent substance is configured to absorb the electromagnetic radiation from the source through the wall and generate fluorescent light in response to the electromagnetic radiation, and wherein the waveguide is configured to guide the fluorescent light emitted by the fluorescent substance towards the optical output element by internally reflecting at least a portion of the fluorescent light, and wherein the optical output element is configured to direct the fluorescent light away from the waveguide; at least one fluid conduit in fluid communication with the inlet and the outlet; a fluid circulation system in fluid communication with the first and second ends of the passage and adapted to circulate the fluorescent substance from the first end to the second end through the passage and from the second end back to the first end through the fluid conduit; and a cooling system configured to cool the fluorescent substance.