First observation of uranium using a diode laser was published recently. The experiment was performed by the optogalvanic spectroscopy using diode lasers. A laser source causes the current change in a hollow cathode discharge lamp when metal atoms in plasma absorb the diode laser light. The optogalvanic signal is collected by detecting the current change. This work is the extended investigation of our previous research, the uranium detection using a diode laser. New electronic transitions of uranium and thorium in 775∼850 nm were investigated using diode lasers. In addition, the Rb(Ⅰ) optogalvanic spectra at 780.02 nm and 794.76 nm were studied. The Rb(Ⅰ) spectrum at 780.02 nm showed the isotopic features and hyperfine splittings. This work provides a key idea that the diode lasers are useful in the specrochemical analysis of the radioactive actinides that have a rich spectrum with transitions which can be easily reached with AlGaAs diode lasers. Also, this study shows that the diode lasers can be an important tool to find the spectroscopic parameters of actinides and rare earth elements which have not known.