Heavy!Shanghai Institute of Optics and Mechanics has made important progress in high-field quantum optics research

Recently, the State Key Laboratory of High-Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, in cooperation with Shanghai Jiaotong University and other units, realized the “photon retention” effect in coherently excited nitrogen ions, which verified the effect of photons on photons in atmospheric ionic gases. Possibility of coherent manipulation. The results were published in Science Bulletin.

Nitrogen is the most abundant gas in the air. A series of recent scientific studies have found that nitrogen ions generated by high-field ionization are a potential new platform for studying quantum coherence effects.

Compared with traditional laboratory gases such as alkali metal vapors, Rydberg quantum gases, and ultracold atoms, nitrogen ions are considered to be a promising candidate for studying light due to their rich energy level structure, relative chemical stability and safety. Novel quantum optics platform for interacting with matter and coherently manipulating properties of photons.

At the same time, due to the abundance of nitrogen molecules in the air, the quantum optics research platform is expected to move from the laboratory to the outdoor atmospheric environment in the near future, enabling coherent manipulation of photons in the atmosphere.

Based on the above reasons, the Shanghai Institute of Optics and Mechanics has cooperated with Shanghai Jiaotong University and other units to verify the photon retention effect in coherently excited nitrogen ion gas.

The study found that after the strong femtosecond laser field ionized nitrogen into nitrogen molecular ions, the quantum coherence properties generated by the femtosecond laser field kept the photons in the ion gas.

These photon information could not be directly detected in previous studies. In this study, the researchers proposed an efficient technique for reading out the photons.

The coherent UV radiation directly observed by the detector can be generated by the co-action of the second mid-infrared laser pulse injected with the delayed injection and the retained photons, thus verifying the coherent photon retention effect in nitrogen ions.

The verification of the photon retention effect in nitrogen, an atmospheric gas, not only confirms that nitrogen ions are an excellent quantum optics research platform, but also points out that in the future, optical information processing and coherent optical information at room temperature can be realized by abundant nitrogen in the outdoor atmosphere in the future. Possibility of storage.

Relevant work has been supported by the National Natural Science Foundation of China, the National Key R&D Program, the Shanghai Municipal Science and Technology Major Project, the Shanghai Outstanding Academic Leader, the Shanghai Natural Science Foundation, the Chinese Academy of Sciences Pilot B Project, and the Chinese Academy of Sciences Youth Promotion Association.

Figure 1. Basic principle of achieving the “photon persistence” effect in coherently excited nitrogen ions.

Figure 2. Ultraviolet coherent radiation generated by trapped photons in coherently excited nitrogen ions. (a) Spectra and (b) time evolution dynamics of experimentally measured UV radiation; (c) theoretically calculated UV radiation intensity as a function of time delay under different population populations of excited states.