Gruneisen Mark T, Miller Warner A, Dymale Raymond C, Sweiti Ayman M
United States Air Force Research Laboratory, Directed Energy Directorate, Kirtland Air Force Base, New Mexico 87117, USA.
Appl Opt. 2008 Feb 1;47(4):A32-42. doi: 10.1364/ao.47.000a32.
There has been considerable interest recently in the generation of azimuthal phase functions associated with photon orbital angular momentum (OAM) for high-dimensional quantum key distribution. The generation of secure quantum keys requires not only this pure phase basis but also additional bases comprised of orthonormal superposition states formed from the pure states. These bases are also known as mutually unbiased bases (MUBs) and include quantum states whose wave functions are modulated in both phase and amplitude. Although modulo 2pi optical path control with high-resolution spatial light modulators (SLMs) is well suited to creating the azimuthal phases associated with the pure states, it does not introduce the amplitude modulation associated with the MUB superposition states. Using computer-generated holography (CGH) with the Leith-Upatnieks approach to hologram recording, however, both phase and amplitude modulation can be achieved. We present a description of the OAM states of a three-dimensional MUB system and analyze the construction of these states via CGH with a phase-modulating SLM. The effects of phase holography artifacts on quantum-state generation are quantified and a prescription for avoiding these artifacts by preconditioning the hologram function is presented. Practical effects associated with spatially isolating the first-order diffracted field are also quantified, and a demonstration utilizing a liquid-crystal SLM is presented.
最近，人们对与光子轨道角动量（OAM）相关的方位角相位函数的生成产生了浓厚兴趣，用于高维量子密钥分发。生成安全的量子密钥不仅需要这种纯相位基，还需要由纯态形成的正交归一叠加态组成的附加基。这些基也被称为相互无偏基（MUBs），包括其波函数在相位和幅度上都被调制的量子态。尽管使用高分辨率空间光调制器（SLM）进行模2π光程控制非常适合创建与纯态相关的方位角相位，但它不会引入与MUB叠加态相关的幅度调制。然而，使用带有利思 - 乌帕特尼克斯全息记录方法的计算机生成全息术（CGH），可以实现相位和幅度调制。我们描述了三维MUB系统的OAM态，并分析了通过使用相位调制SLM的CGH来构建这些态。量化了相位全息术伪像对量子态生成的影响，并提出了通过对全息图函数进行预处理来避免这些伪像的方法。还量化了与空间隔离一阶衍射场相关的实际影响，并给出了利用液晶SLM的演示。
