Cascaded downconversion for multi-photon entanglement and quantum information processing

源于光子学研究的技术在我们的现代世界无处不在，从激光手术到条形码扫描仪，再到通过数公里长的光纤在互联网上向世界各地发送信息的光学信号。我们现在正在进入一场新的光学革命。在这个光子学的新时代，信息将存储在光子--光的单个粒子--的量子态中。利用量子力学有时违反直觉的特性，将带来非凡的新技术，从由物理定律保证的完全安全的通信，到能够处理任何经典计算机都无法解决的问题的新型计算机。 为了利用这些技术，必须开发创建、操作和检测单个光子的量子态的工具。尽管近年来在这一方向上取得了很大进展，但以量子方式创造光子并与之相互作用的方法仍然令人惊讶地少之又少。最近，我们演示了一种精确实现这一点的方法：级联下变频。这项技术为量子态的产生带来了很大的希望，使我们能够以一种以前不可能实现的方式创建态。然而，它还没有得到令人满意的调查。在这个NSERC发现计划中，我提议彻底探索级联下转换在量子信息应用和其他应用中的全部潜力。 这项研究计划将通过在新兴的量子计算领域开发尖端技术，为加拿大带来重大好处。它将为本科生、研究生和博士后研究人员提供高度先进的培训，他们将在实验量子光学和量子信息方面获得宝贵的研究经验。此外，他们还将发展广泛适用的激光、光学和计算机编程的动手技能。

Technologies stemming from photonics research are omnipresent in our modern world, from laser surgery to barcode scanners and optical signals travelling through kilometers of optical fibers sending information all over the world on the internet. We are now entering a new revolution in optics. In this new era of photonics, information will be stored in the quantum states of photons – individual particles of light. Exploiting the sometimes counterintuitive properties of quantum mechanics will allow for remarkable new technologies, from the completely secure communications guaranteed by the laws of physics to a new type computer able to tackle problems that no classical computer could solve. To exploit these technologies, the tools to create, manipulate and detect the quantum states of individual photons must be developed. While much progress has been done in this direction in recent years, there are still surprisingly few ways of creating and interacting with photons in a quantum way. Very recently, we have demonstrated a method to do precisely this: cascaded downconversion. This technique holds much promise for the production of quantum states, allowing us to create states in a way which was previously impossible. However it has yet to be satisfactorily investigated. In this NSERC Discovery program, I propose a thorough exploration of the full potential of cascaded downconversion for quantum information applications and beyond. This research program will provide significant benefits to Canada through the development of cutting edge technologies in the burgeoning field of quantum computing. It will deliver highly advanced training for undergraduate students, graduate students and postdoctoral researchers, who will gain invaluable research experience in experimental quantum optics and in quantum information. In addition they will develop widely applicable hands-on skills with lasers, optics and computer programming.