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USTC Firstly and Successfully Develops All-optical Controlled Nonreciprocal Microcavity Device

release time:2016-08-24   Click on:1808

Quantum information key laboratory of Chinese Academy of Sciences (CAS) leaded by Guo Guangcan, the academician of CAS and professor of USTC, has significant progress in cavity optical mechanics. Dong Chunhua research team and post-doctor Zou Changling firstly observes nonreciprocal optical properties based on in microcavity of whispering gallery mode and obtains the all-optical controlled nonreciprocal microcavity device. The paper is published on line on on 22nd August.
     

The light has two-way transmission reciprocity in a general medium, yet in a photon integrated circuit, the undirectional control of light is one of the basic requirements in quantum information processing, so the all-optical controlled opto-isolator, circulator and nonreciprocal phase shifter are always the study hotspot of optical chips. These optical devices are based on optical nonreciprocal property. The general nonreciprocal device is based on characteristics of magneto-optic material which always requiring strong magnetic field and being difficult to integrate small size, thus there is still a great challenge on the realization of all-optical nonreciprocal devices with integration feasible.
     

Using optical force interaction familiar in microcavity of whispering gallery mode in the experiment, the difference is the optical model is a traveling wave mode of two degenerate clockwise and anti-clockwise. The two degenerate optical models have completely opposite orbital angular momentum. Under the condition of satisfying the matching of angular momentum, the drive light can stimulate the coherent conversion of signal photon and phonon only when the drive light and signal light coupled to the same optical mode, thus resulting in nonreciprocal property of light propagation. Based on this, the research team realizes the nonreciprocal phenomenon of optical mechanics induced transparency and amplification caused by one-way undirectional drive light, and achieves nonreciprocal phase shifting up to 40 degrees, which is the basis to achieve opto-isolator and circulator. The non-reciprocity induced by light force system can pass through driver light of opposite directional propagation, and simultaneously stimulate traveling wave mode of clockwise and anti-clockwise for controlling to further achieve coherent conversion of the two optical modes. This feature can also be used for tunable narrow-band reflector. The experimental study of nonreciprocal mechanism has universality which can be promoted to any traveling wave model system with mechanical vibration to realize integrated microcavity chip components, even opto-isolator of single photon level. Besides, the nonreciprocal phase shifting property in this experiment can also be used for research on topological properties to realize chirality edge state and topology protection.


 

 

(a) sketch for nonreciprocal optical experiment of cavity light force system;

(b) sketch for optical mechanics induced transparency and amplification (OMIT)

(c-f) nonreciprocal property spectrum


The study is an extension of the research on Brillouin nonreciprocal property carried out by the team last year. Cavity optical mechanics system is enlarged to be appropriate for nonreciprocal device, and the operating wavelength extends to entire optical wavelength even microwave, especially at quantum ground state of the system, so as to make optical isolation of single photon being possible. And this will play an important role in the aspect of recombination quantum in future.
     

The above study obtained supports from Ministry of Science and Technology of China, Chinese Academy of Sciences, Natural Sciences Foundation, Collaborative Innovation Center of Quantum Information and Frontier Quantum Science & Technology, Fostering Foundation for significant project of USTC.

Paper link attached:

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