Doppler-free, multiwavelength acousto-optic deflector for two-photon addressing arrays of Rb atoms in a quantum information processor

Abstract

We demonstrate a dual wavelength acousto-optic deflector (AOD) designed to deflect two wavelengths to the same angles by driving with two RF frequencies. The AOD is designed as a beam scanner to address two-photon transitions in a two-dimensional array of trapped neutral Rb87 atoms in a quantum computer. Momentum space is used to design AODs that have the same diffraction angles for two wavelengths (780 and 480 nm) and have nonoverlapping Bragg-matched frequency response at these wavelengths, so that there will be no cross talk when proportional frequencies are applied to diffract the two wavelengths. The appropriate crystal orientation, crystal shape, transducer size, and transducer height are determined for an AOD made with a tellurium dioxide crystal (TeO(2)). The designed and fabricated AOD has more than 100 resolvable spots, widely separated band shapes for the two wavelengths within an overall octave bandwidth, spatially overlapping diffraction angles for both wavelengths (780 and 480 nm), and a 4 micros or less access time. Cascaded AODs in which the first device upshifts and the second downshifts allow Doppler-free scanning as required for addressing the narrow atomic resonance without detuning. We experimentally show the diffraction-limited Doppler-free scanning performance and spatial resolution of the designed AOD.

Single-site Rydberg addressing in 3D atomic arrays for quantum computing with neutral atoms

“…First, the timing synchronization of the laser pulses can be realized by using acousto-optic multi-channel modulators made with tellurium dioxide crystals, which can deflect multiple laser beams [60]. To address arrays of rubidium atoms with two-photon excitation of Rydberg states, a Doppler-free multiwavelength (780 and 480 nm) acousto-optic deflector was experimentally demonstrated about a dozen years ago [61]. The deflector in [61] can simultaneously diffract the two incident optical wavelengths with a common diffraction angle.…”

“…To address arrays of rubidium atoms with two-photon excitation of Rydberg states, a Doppler-free multiwavelength (780 and 480 nm) acousto-optic deflector was experimentally demonstrated about a dozen years ago [61]. The deflector in [61] can simultaneously diffract the two incident optical wavelengths with a common diffraction angle. So, it is possible to realize a multi-channel modulator for deflecting several laser lights.…”

Broadband acoustooptic diffraction of two-wavelength light in paratellurite

“…A similar device enabling independent control of two wavelengths has been described in the recent study [4]. However, no calculation details have been given there, so that justification of the cell geometry selected by the authors still remains not obvious and, moreover, the control of different wavelengths has been performed by separate ultrasonic transducers, which complicates both construction and driving electronics of the device.…”

Multiplexed broadband beam steering system utilizing high speed MEMS mirrors

“…While these strategies have an advantage in speed, their limitations present significant obstacles. Both acousto-optical deflectors and electro-optical deflectors have to be wavelength tuned and require complex engineering to incorporate multiple wavelengths [12]. In addition, acousto-optical deflectors need ∼ 1 W RF drive power and induce small frequency shifts in the laser that must be accounted for, while electro-optical deflectors need large operation voltages and have limited angular range.…”