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USTC Achieves Quantum Frequency Conversion Of Orbit Angular Momentum (OAM) Photon

release time:2016-10-09   Click on:2302

Quantum information key laboratory of Chinese Academy of Sciences(CAS) leaded by Guo Guangcan, the academician of CAS and professor of USTC, has series progress in the study of quantum frequency conversion of OAM photon: the team leaded by professor Shi Baosen of this laboratory firstly realizes frequency conversion of OAM single photon, OAM entangled photon, and the mixed entangled photon constituted by OAM and polarization, demonstrates the unchanged quantum coherence and entanglement of photon pairs in frequency conversion. The main study achievements published in international optics authorative journal - [Light: Sci. & Appl. 5, e16019 (2016)] and international physics authorative journal - [Phys. Rev. Lett. 117, 103601(2016)] respectively.

Light beam carrying OAM has significant applications in precision measurement, captivity and manipulation of tiny particles, basic physics study and other fields. Meanwhile, optical information processing based on OAM coding becomes a hot research topic in optical communication field for the advantage of large capacity of the channel. Construction of high dimensional quantum network based on OAM coding is an important research direction in quantum information field, and many breakthrough progresses has been obtained in recent years, such as Shi Baosen team firstly realize the storage of OAM single photon [Nat. Commun. 4, 2527 (2013)] and OAM entangled quantum [Phys. Rev. Lett., 114, 050502 (2015)] in the world. In quantum communication, photon as information carrier needs transmission in low loss communication window, while as a physical system of information storage and processing unit, the operating wavelength generally is not at communication window, so quantum interface is required to be set up between them to satisfy the basic requirement of the quantum information storage and long distance transmission. Photon frequency conversion based on nonlinear process is an effective method for establishing quantum interface. A converter that can realize this function shall be called quantum frequency converter, its basic requirement is frequency of a photon can be changed as needed, but more important is it cannot destroy quantum correlation and coherence of the original quantum state. Although people have achieved frequency conversion of gauss single photon and entangled photon, but so far it is still an “open question” that whether and how to realize frequency conversion of OAM photon and OAM entangled photon.  

Professor Shi Baosen from quantum information key laboratory of CAS   and post-doctor Zhou Zhiyuan, etc. carried out nonlinear frequency conversion of light beam carrying OAM from 2012, gained a series of progress [OL37, 3270 (2012), PRA85, 053815 (2012); OE 22, 20298(2014);OE 22, 23673(2014); J. Opt. Soc. Am. B 32, 407 (2015) ], and had significant breakthrough based on this: They use periodic nonlinear crystal as a frequency conversion medium, improve the conversion efficiency by adopting external cavity resonance technology, firstly and successfully realize the frequency conversion of OAM single photon from the infrared to the visible wave band, and demonstrate the unchanged nonclassical correlation of the photon and coherence of quantum in the process of frequency conversion, take an important step in realizing quantum interface based on the frequency converter [light: Science & Applications 5, e16019 (2016)]. Recently, they have to upgrade the technology to a new high recently, they promote the technology to a whole new level recently: Firstly realize the frequency conversion from the infrared to the visible wave band of OAM entangled photon and mixed entangled photon consisting by OAM entangled photon and polarization, and verify the unchanged photon entanglement properties in the process of conversion [Phys. Rev. Lett. 117, 103601 (2016)]. This series of work has great significance in realizing OAM quantum network connection and quantum information interaction operating at different wavelengths.



Sketch for frequency conversion of OAM entangled photon

This series of work also opened up a new chapter in quantum optics and nonlinear optics research. It has important values for research on high dimensional OAM quantum state coherent wavelength conversion, up-conversion detection of complex space optical field under very weak light intensity and preparation of OAM light beam with short wavelength. Besides, due to significant function of infrared image signal in remote sensing, night vision, astronomical observation, and other fields, the high precision detection of infrared image is very important. While the commonly used infrared detector has some problems such as low precision, resolution ratio not high, low detection efficiency and equipment is expensive. An effective way to solve the above problems is converting the image signal to visible wave band by frequency up-conversion, using the high precision, high sensitivity and low prices of the visible wave band detection device for detecting. The series of achievements obtained by Shi Baosen team has important value in establishing the infrared signal up-conversion detectors, and solving the detection of infrared image signal especially weak signal.

Post-doctor Zhou Zhiyuan contributes as the first author of the paper. The job obtained finance from Natural Sciences Foundation, Chinese Academy of Sciences, Ministry of Science and Technology of China, Collaborative Innovation Center of Quantum Information and Frontier Quantum Science & Technology.

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