[en] In this paper, we tried to reduce the velocity-changing-collision (VCC) effects in an La hollow cathode discharge lamp by a polarization intermodulated excitation(POLINEX) method. For an atomic excitation laser, we used a single-mode tunable diode laser with an external cavity. The power of the diode laser was amplified to more than 500 mW by using a master-oscillator power-amplifier (MOPA) configuration. As a result, when a POLINEX method is adopted, we can observe a decrease of VCC effects in 675.304 transition lines of La, compared with the case of saturation absorption spectroscopy

[en] Sub-Doppler spectra of ¹³⁹La I were measured for four transition lines by using saturation absorption spectroscopy. For an atomic excitation laser, we used a single- mode tunable diode laser with a master-oscillator power-amplifer configuration. A La-Ar hollow cathode discharge lamp was used to generate La atomic sources. From the obtained spectra, we determined the hyperfine structure of the upper levels and the hyperfine constants A and B of the ¹³⁹La isotope. Additionally, when the polarization intermodulated excitation method was adopted, we could observe a decrease of velocity-changing-collision effects in the 675.30 nm transition line of La, compared with the case of saturation absorption spectroscopy