Ultraviolet laser spectroscopy of aluminum atoms in hollow-cathode lamp

We report on the precision measurement of aluminum atoms P-2(1/2) - S-2(1/2) transition at 394 nm and P-2(3/2) - S-2(1/2) transition at 396 nm in a hollow-cathode lamp. Both absorption and saturated absorption spectra are measured. From the absorption spectra, the Doppler linewidth is estimated to be 2.65 GHz. The saturated absorption spectra are analyzed based on a velocity-changing collisions model. With a frequency comb calibrated wavemeter, the frequencies of P-2(1/2)(F' = 3) - S-2(1/2)(F = 2) transition and P-2(3/2)(F' = 4) - S-2(1/2)(F = 3) transition are measured to be 759.905 204(1) THz and 756.547 133(3) THz, respectively. The hyperfine coupling constants of aluminum atoms are determined, and are compared with previously reported measurement results and theoretical calculation results. Reasonable agreement is found for the magnetic dipole constant (A constant), while the electric quadrupole constant (B constant) has a large deviation.