21-watts intracavity-frequency-doubled all-solid-state light source at 671 nm for laser cooling of lithium

Abstract

Abstract:We present an all-solid-state laser source emitting up to 2.1 W of single-frequency light at 671 nm developed for laser cooling of lithium atoms. It is based on a diode-pumped, neodymium-doped orthovanadate (Nd:YVO 4 ) ring laser operating at 1342 nm. Optimization of the thermal management in the gain medium results in a maximum multi-frequency output power of 2.5 W at the fundamental wavelength. We develop a simple theory for the efficient implementation of intracavity second harmonic generation, and its application to our system allows us to obtain nonlinear conversion efficiencies of up to 88%. Single-mode operation and tuning is established by adding an etalon to the resonator. The second-harmonic wavelength can be tuned over 0.5 nm, and mode-hop-free scanning over more than 6 GHz is demonstrated, corresponding to around ten times the laser cavity free spectral range. The output frequency can be locked with respect to the lithium D-line transitions for atomic physics applications. Furthermore, we observe parametric Kerr-lens mode-locking when detuning the phase-matching temperature sufficiently far from the optimum value.

A self-injected, diode-pumped, solid-state ring laser for laser cooling of Li atoms

“…In our sys- tem, this factor is observed to be 0.76, which is consistent with the ratio of the cavity lengths of our actual setup. A mode-hop-free tuning range of 8 GHz at 1342 nm has been achieved, which is wider than the 3 GHz realized in the previous work 9 . Figure 2 shows the output power of the 1342 nm laser as a function of the total pump power at 808 nm.…”

“…In previous works, single-longitudinal-mode lasers at 671 nm have been produced with the combination of a Nd:YVO 4 ring laser and a frequency doubler [6][7][8][9] . In these studies, unidirectional lasing was realized by placing an optical diode comprised of a terbium gallium garnet (TGG) crystal and half-wave plate inside the ring cavity.…”

“…The high absorption coefficient of TGG produces both a direct optical loss as well as a loss due to thermal depolarization a) Electronic mail: muka@ils.uec.ac.jp which limits the power scaling of such ring lasers. 9 . Alternatively, one circulating mode can be favored over the other by retro-reflecting one of the two output beams back into the cavity [10][11][12][13] .…”

Low noise continuous‐wave single‐frequency dual wavelength lasers at 671 and 1342 nm

“…12 In 2013, Eismann et al lowered the quantum defect by employing 888 nm laser diode (LD) pumping, 2.1 W 671 nm laser in CW single frequency operation was obtained using a periodically poled KTiOPO 4 (PPKTP) based intracavity second harmonic generation (ICSHG) device. 13 In 2018, we demonstrated a mode-hop-free laser with 11.3 W output at 1342 nm and 0.3 W output at 671 nm by controlling the nonlinear loss induced by ICSHG. 14,15 To the best of our knowledge, there was no report on generating CW single frequency lasers at 1342 and 671 nm with powers exceeding 2 W simultaneously using a single oscillator.…”

“…In 2012, Zheng et al optimized the cavity design by taking into account the influence of the ESA on the thermal lens of the laser crystal, the maximal output powers of 2.8 W at 671 nm and 850 mW at 1342 nm were achieved simultaneously 12 . In 2013, Eismann et al lowered the quantum defect by employing 888 nm laser diode (LD) pumping, 2.1 W 671 nm laser in CW single frequency operation was obtained using a periodically poled KTiOPO 4 (PPKTP) based intracavity second harmonic generation (ICSHG) device 13 . In 2018, we demonstrated a mode‐hop‐free laser with 11.3 W output at 1342 nm and 0.3 W output at 671 nm by controlling the nonlinear loss induced by ICSHG 14,15 .…”