Ditellurium Spectroscopy for Titanium Laser Cooling and Locking

We demonstrate the use of ditellurium (¹³⁰Te₂) as a frequency reference for laser locking at 391 nm and 498 nm optical wavelengths, which are of interest for titanium laser cooling experiments. In a 256 GHz range near 391 nm, we use Doppler-free saturated absorption spectroscopy to observe 36 transitions of the X0_u⁺ → B0_g⁺ electronic system. We measure the frequency of these lines, as well as those around 498 nm, relative to optical pumping and cooling transitions in atomic Ti. Subsequently, we stabilize lasers at 391 nm (498 nm) to ∼60 MHz (∼50 MHz) wide resonances in ¹³⁰Te₂ near the respective transitions in Ti. We observe robust long-term frequency locks, with Allan deviations of 4.9 × 10^-10 (3.6 × 10^-11) at 10 s of averaging time for the 391 nm (498 nm) laser. These results extend ¹³⁰Te₂ frequency references down to 391 nm, providing suitable transitions for laser locking.