Microwave control electrodes for scalable, parallel, single-qubit operations in a surface-electrode ion trap
Applied Physics B Springer Nature 114:1-2 (2014) 3-10
Injection locking of two frequency-doubled lasers with 3.2 GHz offset for driving Raman transitions with low photon scattering in 43Ca+
Optics Letters 38:23 (2013) 5087-5089
Abstract:
We describe the injection locking of two infrared (794 nm) laser diodes that are each part of a frequency-doubled laser system. An acousto-optic modulator in the injection path gives an offset of 1.6 GHz between the lasers for driving Raman transitions between states in the hyperfine split (by 3.2 GHz) ground level of 43Ca+. The offset can be disabled for use in 40Ca+. We measure the relative linewidth of the frequency-doubled beams to be 42 mHz in an optical heterodyne measurement. The use of both injection locking and frequency doubling combines spectral purity with high optical power. Our scheme is applicable for providing Raman beams across other ion species and neutral atoms where coherent optical manipulation is required. © 2013 Optical Society of America.A microfabricated ion trap with integrated microwave circuitry
ArXiv 1210.3272 (2012)
Abstract:
We describe the design, fabrication and testing of a surface-electrode ion trap, which incorporates microwave waveguides, resonators and coupling elements for the manipulation of trapped ion qubits using near-field microwaves. The trap is optimised to give a large microwave field gradient to allow state-dependent manipulation of the ions' motional degrees of freedom, the key to multiqubit entanglement. The microwave field near the centre of the trap is characterised by driving hyperfine transitions in a single laser-cooled 43Ca+ ion.Background-free detection of trapped ions
Applied Physics B: Lasers and Optics 107:4 (2012) 1175-1180
Abstract:
We demonstrate a Doppler cooling and detection scheme for ions with low-lying D levels which almost entirely suppresses scattered laser light background, while retaining a high fluorescence signal and efficient cooling. We cool a single ion with a laser on the 2S1/2 ?2P1/2 transition as usual, but repump via the 2P3/2 level. By filtering out light on the cooling transition and detecting only the fluorescence from the 2P3/2 → 2S1/2 decays, we suppress the scattered laser light background count rate to 1 s-1 while maintaining a signal of 29000 s-1 with moderate saturation of the cooling transition. This scheme will be particularly useful for experiments where ions are trapped in close proximity to surfaces, such as the trap electrodes in microfabricated ion traps, which leads to high background scatter from the cooling beam.Heating rate and electrode charging measurements in a scalable, microfabricated, surface-electrode ion trap
Applied Physics B: Lasers and Optics 107:4 (2012) 913-919