Effective multiple sideband generation using an electro-optic modulator for a multiple isotope magneto-optical trap

Abstract

Herein, we report an effective method for the generation of radio-frequency (RF) sidebands in an electro-optic modulator for the simultaneous magneto-optical trapping of two isotopes. This is achieved by switching the RF signals alternately, which suppresses the generation of unwanted frequency signals and improves the laser power per sideband. The generated sidebands are successfully applied to a dual-rubidium-isotope magneto-optical trap (MOT), which results in an increased number of trapped atoms. This simple, flexible, and robust technique can be implemented in experiments that require a large number of atoms in multiple-isotope MOTs and for various applications.

Setup for the Ionic Lifetime Measurement of the 229mTh3+ Nuclear Clock Isomer

“…Before the two laser beams can be sent to the vacuum chamber for hyperfine structure spectroscopy, they need to be modified in their respective spectrum to address either 229 Th 3+ or 229m Th 3+ . For this purpose, the respective laser shall be guided through an electro-optic modulator (EOM) that is driven with selected RF voltages, which is a common procedure in atomic and laser physics experiments [30,[57][58][59][60]. Exactly at these radiofrequencies, the EOMs (PM705 for 690 nm and PM980 for 984 nm; JENOPTIK Optical Systems GmbH, Jena, Germany) generate spectral sidebands around the chosen center frequencies, which in turn drive all necessary hyperfine transitions to prevent the generation of dark states during spectroscopy.…”

“…The electronic system to generate and combine the RF frequencies before application to the respective EOM, follows the design by Uchiyama et al [60]. However, we use direct digital synthesizer boards (AD9914; Analog Devices Inc., Wilmington, MA, USA) instead of stabilized VCOs.…”

Fundamental physics with cold radioactive atoms

“…In total, three RF frequencies, 6586 MHz, 5460 MHz and 2527 MHz, and the carrier frequency are needed for the trapping of two isotopes and are obtained through multiple sideband generation. We already demonstrated to measure the magnetic field and VLS with this developed dual species comagnetometer, and this technique can be applied to reduce the dominant systematic error for the magnetic field change and VLS [16]. Rb with an ECDL.…”