Abstract: This invention relates to an automated apparatus for use with electromagnetic radiation, such as a laser beam, to promote chemical reactions. The reaction chamber apparatus comprises a cylinder equipped with a reciprocating piston and with one or more windows. The invention also comprises an automated system which utilizes said chamber, and a method for utilizing the chamber and system. A laser beam enters the cylinder through one window, activates the reagents therein, and exits the chamber through a second window. After a mixture has been reacted, the laser is placed on standby, and the piston reciprocates, filling the cylinder with fresh reagent. Various embodiments are described which improve the efficiency of this invention.