Laser cooling of beryllium ions using a frequency-doubled 626 nm diode laser
Opt. Lett., vol. 38, no. 13, pp. 2370-2372 (2013).
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We demonstrate laser cooling of trapped beryllium ions at 313 nm using a frequency-doubled extended cavity diode laser operated at 626 nm, obtained by cooling a ridge waveguide diode laser chip to -31°C. Up to 32 mW of narrowband 626 nm laser radiation is obtained. After passage through an optical isolator and beam shaping optics, 14 mW of 626 nm power remains of which 70% is coupled into an external enhancement cavity containing a nonlinear crystal for second-harmonic generation. We produce up to 35 µW of 313 nm radiation, which is subsequently used to laser cool and detect 6 × 102 beryllium ions, stored in a linear Paul trap, to a temperature of about 10 mK, as evidenced by the formation of Coulomb crystals. Our setup offers a simple and affordable alternative for Doppler cooling, optical pumping, and detection to presently used laser systems.
1 LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
3 Optical Metrology, Institut für Physik, Humboldt-Universität zu Berlin, 10117 Berlin, Germany´
(140.2020) Diode lasers; (140.3320) Laser cooling; (140.3610) Lasers, ultraviolet; (140.7300) Visible lasers; (270.5585) Quantum information and processing; (300.6520) Spectroscopy, trapped ion.