Abstract
The saturated absorption spectrum of the 6P3/2→7S1/2 transition of 203Tl and 205Tl in a hollow cathode lamp has been observed with a frequency-doubled 1070 nm Nd:GdVO4 laser. The third-derivative spectrum of the hyperfine components are obtained using the wavelength modulation spectroscopy and used to stabilize the laser frequency. The analysis of the error signal shows that the frequency stability reaches 30 kHz at 1 s averaging time. Such a frequency-stabilized light source at 535 nm can be used for laser cooling of thallium and for investigating the parity non-conservation effect in thallium. The absolute frequencies of hyperfine components are measured with an accuracy of 30 MHz using a precision wavelength meter. Including the pressure shift correction, the center of gravity of the transition frequency is determined to an accuracy of 22 MHz for both isotopes. Meanwhile, the isotope shift derived is in good agreement with earlier measurement. © 2013 American Physical Society.