Abstract: A cylindrical lens (4) diverges a laser beam (L1) in the Y-axis direction (i.e., within the YZ plane) but neither diverges nor converges it in the X-axis direction (i.e., within the ZX plane). An objective lens (5) converges the laser beam (L1) emitted from the cylindrical lens (4) into a point P1 in the Y-axis direction and into a point P2 in the X-axis direction. A pair of knife edges (13) adjust the divergence angle (?) of the laser beam (L1) incident on the objective lens (5) in the Y-axis direction. As a consequence, the cross section of the laser beam (L1) becomes an elongated form extending in the Y-axis direction at the point P2, while the maximum length in the Y-axis direction is regulated. Therefore, locating the point P2 on the front face of a work (S) can form an elongated working area extending in the Y-axis direction by a desirable length on the front face of the work (S).

Abstract: A cylindrical lens (4) diverges a laser beam (L1) in the Y-axis direction (i.e., within the YZ plane) but neither diverges nor converges it in the X-axis direction (i.e., within the ZX plane). An objective lens (5) converges the laser beam (L1) emitted from the cylindrical lens (4) into a point P1 in the Y-axis direction and into a point P2 in the X-axis direction. As a consequence, the cross section of the laser beam (L1) becomes elongated forms extending in the X- and Y-axis directions at the points P1, P2, respectively. Therefore, when the points P1, P2 are located on the outside and inside of the work (S), respectively, an elongated working area extending in the Y-axis direction can be formed in a portion where the point P2 is positioned within the work (S).

Abstract: A total reflection terahertz wave measuring apparatus 1 includes a light source 11, a branching part 12, a chopper 13, an optical path length difference adjusting part 14, a polarizer 15, a beam splitter 17, a terahertz wave generating element 20, a filter 25, an internal total reflection prism 31, a terahertz wave detecting element 40, a ¼ wavelength plate 51, a polarization split element 52, a photodetector 53a, a photodetector 53b, a differential amplifier 54, and a lock-in amplifier 55. The internal total reflection prism 31 is a so-called aplanatic prism, and has an entrance surface 31a, an exit surface 31b, and a reflection surface 31c. The terahertz wave generating element 20 and the filter 25 are provided to be integrated with the entrance surface 31a of the internal total reflection prism 31, and the terahertz wave detecting element 40 is provided to be integrated with the exit surface 31b of the internal total reflection prism 31.

Abstract: A total reflection terahertz wave measuring apparatus 1 is configured to acquire information on a subject S by a total reflection measurement method by use of a terahertz wave, and includes a light source 11, a branching part 12, a chopper 13, an optical path length difference adjusting part 14, a polarizer 15, a separator 17, a terahertz wave generating element 20, an internal total reflection prism 31, a terahertz wave detecting element 40, a ¼ wavelength plate 51, a polarization split element 52, a photodetector 53A, a photodetector 53B, a differential amplifier 54, and a lock-in amplifier 55. The internal total reflection prism 31 is a so-called aplanatic prism, and has an entrance plane 31a, an exit plane 31b, and a reflection plane 31c.

Abstract: A cylindrical lens (4) diverges a laser beam (L1) in the Y-axis direction (i.e., within the YZ plane) but neither diverges nor converges it in the X-axis direction (i.e., within the ZX plane). An objective lens (5) converges the laser beam (L1) emitted from the cylindrical lens (4) into a point P1 in the Y-axis direction and into a point P2 in the X-axis direction. A pair of knife edges (13) adjust the divergence angle (?) of the laser beam (L1) incident on the objective lens (5) in the Y-axis direction. As a consequence, the cross section of the laser beam (L1) becomes an elongated form extending in the Y-axis direction at the point P2, while the maximum length in the Y-axis direction is regulated. Therefore, locating the point P2 on the front face of a work (S) can form an elongated working area extending in the Y-axis direction by a desirable length on the front face of the work (S).

Abstract: A total reflection terahertz wave measuring apparatus 1 includes a light source 11, a branching part 12, a chopper 13, an optical path length difference adjusting part 14, a polarizer 15, a beam splitter 17, a terahertz wave generating element 20, a filter 25, an internal total reflection prism 31, a terahertz wave detecting element 40, a ¼ wavelength plate 51, a polarization split element 52, a photodetector 53a, a photodetector 53b, a differential amplifier 54, and a lock-in amplifier 55. The internal total reflection prism 31 is a so-called aplanatic prism, and has an entrance surface 31a, an exit surface 31b, and a reflection surface 31c. The terahertz wave generating element 20 and the filter 25 are provided to be integrated with the entrance surface 31a of the internal total reflection prism 31, and the terahertz wave detecting element 40 is provided to be integrated with the exit surface 31b of the internal total reflection prism 31.

Abstract: An optical element 20A which is composed of a light transmission characteristic medium, that has a refractive index higher than a refractive index of air, the optical element causes an incident laser beam to be propagated inside while reflecting the laser beam by a wall surface 20a a plurality of times, the optical element includes an incident window 21 which is located in a part of the wall surface 20a, that is for allowing the laser beam to be incident, an emitting window 22 which is located in a part of the wall surface 20a, that is for allowing the laser beam propagated inside to be emit, and wavelength dispersion compensating units 31 and 32 which are integrally located in parts of the medium, the wavelength dispersion compensating units compensate for wavelength dispersion by causing the laser beam to be transmitted or reflected at least twice.