Kim Sangtaek, Mcleod Robert R, Saffman M, Wagner Kelvin H
Department of Electrical and Computer Engineering, Optoelectronic Computing Systems Center, University of Colorado at Boulder, Boulder, Colorado 80309, USA.
Appl Opt. 2008 Apr 10;47(11):1816-31. doi: 10.1364/ao.47.001816.
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.
我们展示了一种双波长声光偏转器（AOD），它通过用两个射频频率驱动，将两个波长偏转到相同角度。该AOD被设计为光束扫描器，用于量子计算机中二维捕获中性铷87原子阵列中的双光子跃迁。利用动量空间设计AOD，使其对两个波长（780和480纳米）具有相同的衍射角，并且在这些波长处具有不重叠的布拉格匹配频率响应，这样当应用比例频率来衍射这两个波长时就不会有串扰。对于用二氧化碲晶体（TeO₂）制成的AOD，确定了合适的晶体取向、晶体形状、换能器尺寸和换能器高度。所设计和制造的AOD具有100多个可分辨光斑，在整个倍频程带宽内两个波长具有宽分离的带宽形状，两个波长（780和480纳米）在空间上重叠的衍射角，以及4微秒或更短的接入时间。级联AOD，其中第一个器件进行上变频，第二个器件进行下变频，可实现无多普勒扫描，这是寻址窄原子共振而不失谐所必需的。我们通过实验展示了所设计AOD的衍射极限无多普勒扫描性能和空间分辨率。
