139 GHz UV phase-locked Raman laser system for thermometry and sideband cooling of ⁹Be⁺ ions in a Penning trap

Abstract

We demonstrate the phase locking of two ultraviolet (UV) laser sources by modulating a fundamental infrared (IR) laser with fourth-order sidebands using an electro-optic modulator and the phase locking of one sideband to a second fundamental IR laser. Subsequent sum frequency generation and second harmonic generation successfully translates the frequency offset to the UV domain. The phase lock at 139 GHz is confirmed through stimulated Raman transitions for the thermometry of 9Be+ ions confined in a cryogenic Penning trap. This technique might be used for the sideband cooling of single 9Be+ ions as well as sympathetic cooling schemes and quantum-logic-based measurements in Penning traps in the future.

Penning micro-trap for quantum computing

“…The former requires the use of two 313 nm lasers phase-locked at the qubit frequency, which we achieve using the method outlined in ref. 39 . By choosing different orientations of Raman laser paths, we can address the radial or axial motions, or implement single-qubit rotations using a co-propagating Raman beam pair.…”

Generation of visible Raman operation laser by a fiber electro-optical modulator feedback loop

“…Phase-coherent multi-tone lasers play a crucial role in the fields of modern information technology, e.g., optical microwave generation [1][2][3][4] , and atomic physics, e.g. atomic clocks [5][6][7] , quantum precision measurement [8][9][10][11][12][13] , and qubits manipulation [14][15][16][17][18] . Among them, the stimulated Raman transition is widely used to manipulate atomic hyperfine qubits [19,20] , and the Raman operation laser typically requires optical fields with gigahertz-level frequency difference to match the atomic energy levels.…”