Time-resolved surface temperature of single crystal silicon was measured by an infrared radiation pyrometer. The silicon sample was irradiated by two pulsed Nd:YAG lasers with pulse duration of 1ms superposed by 7ns pulses, referred to as combined pulse laser (CPL). The change of the damage radius with the millisecond (ms) laser energy density was studied, and then compared with that of single ms laser irradiation. An axisymmetric numerical model was established for calculation of the temperature field distribution while silicon was irradiated by single ms laser and CPL, respectively. Compared with experimental results, the CPL-silicon damage mechanism was discussed.
A real-time method based on laser scattering technology was used to detect the interaction process of GaAs with a 1080 nm laser. The detector collected the scattered laser beam from the GaAs wafer. The main scattering sources were back surface at first, later turn into front surface and vapor, so scattering signal contained much information of the interaction process. The surface morphologies of GaAs with different irradiation times were observed using an optical microscope to confirm occurrence of various phenomena. The proposed method is shown to be effective for the real-time detection of GaAs. By choosing a proper wavelength, the scattering technology can be promoted in detection of thicker GaAs wafer or other materials.