The invention relates to a two-tone
femtosecond laser collinear pumping detecting thermal reflection
system which comprises a polarization output pulse
laser, a wave plate, a
beam splitting element, a reflecting mirror, an electro-
optical modulator, a frequency doubling
crystal, an
optical filter, a
beam expander, an electronic control displacing platform, a cold-light mirror, a fixing adjusting frame, a focusing lens, a photoelectric
detector and a filter
amplifier, wherein the polarization output pulse
laser is used for outputting a pulse laser; the wave plate is used for causing the laser to rotate along a polarization direction; the laser beam is divided into two mutually vertical beams along the polarization direction by the
beam splitting element; the laser beam is received and reflected by the reflecting mirror; the laser beam is modulated by the electro-
optical modulator; the frequency doubling
crystal is used for causing the laser to generate second
harmonics; the laser within an appointed
wavelength interval is filtered by the
optical filter; the
diameter of the laser beam is expanded by the
beam expander; the electronic control displacing platform can move back and forth; the
laser beams with different wavelengths are combined by the cold-light mirror; a sample is fixed by the fixing adjusting frame; the laser is irradiated on the surface of the sample by the focusing lens; the photoelectric
detector is used for receiving the laser passing through the
optical filter and generating an
electric signal; and the
signal of the photoelectric
detector is amplified by the filter
amplifier. According to the two-tone
femtosecond laser collinear pumping detecting thermal reflection
system,
femtosecond pulse lasers with different wavelengths are applied to pumping light and detecting light; the pumping light after being subjected to frequency doubling is filtered by the optical filter with high selective permeability; the interference of the pumping light to a detecting
signal is avoided; and the accurate high-efficient measurement is realized.