摘要 |
New mode of radiant heating wherein two different wavelength pulses (FIG. 7, 42, 43) are used to melt portions of a solid body (41). The first pulse may be of relatively weak intensity, but is strongly absorbed by the solid. The second pulse, which is not strongly absorbed by the body when in the solid phase, is strongly absorbed by the body when in the molten phase. Exposure to the first pulse results in an initial melting of the body, which then becomes highly absorptive to radiation at the wavelength of the second pulse. Readily available radiant energy sources, e.g., lasers, which generate radiations generally not highly absorbed by the body in the solid phase may thus be efficiently utilized. |