Extended Data Fig. 2: Scheme of the optical setup.
From: Laser spectroscopic characterization of the nuclear-clock isomer 229mTh
The spectroscopy laser of the first step excitation (484 nm) is locked to the wavemeter, which is calibrated by a Rb-stabilized ECDL at 780 nm. The second-step (1,164 nm) laser tuning is monitored with the confocal cavity. The ECDL at 459 nm is used to detect the number of ions in the traps. The loading of Th2+ in the PTB trap is provided by ablation (nanosecond Nd:YAG laser at 1,064 nm) and further three-photon ionization. The first step uses a 402-nm ECDL, pulsed via an acousto-optical modulator (AOM), and the second and third steps involve third-harmonic generation (THG) of a nanosecond Ti:Sa laser. Molecular compounds of Th+ are photodissociated by pulses from a Q-switched diode-pumped solid-state laser (Q-DPSS).
