| 摘要 |
PURPOSE: An apparatus for measuring a speed of a high temperature object and a method thereof are provided, which measures a transportation speed of the object accurately, by maintaining a constant intensity and polarization of two beams incident on the high temperature object and by removing a noise light generated at the high temperature. CONSTITUTION: The apparatus includes a semiconductor laser(21) radiating a laser beam, and a Brag cell(22) dividing the laser beam radiated from the semiconductor laser into two beams having different frequencies each other, and a bending mirror(23) bending two laser beams divided by the Brag cell, and optical fibers(24,25) which are connected to the bending mirror respectively and transport the bent laser beams respectively. And a sensor head(27) is constituted to radiate the laser beam transported by the optical fibers to a steel(26). The sensor head includes polarization beam splitters(28,29) dividing the laser beam into a vertically polarized beam and a horizontally polarized beam, and bending mirrors(30,31) bending the horizontally polarized beam, and polarization diffraction gratings(32,33) converting the horizontally polarized beam bent in the bending mirrors into a vertically polarized beam. |
