Anti-Parity-Time Symmetric Optical Four-Wave Mixing in Cold Atoms
Non-Hermitian optical systems with parity-time (PT) symmetry have recently revealed many intriguing prospects that outperform conservative structures. The previous works are mostly rooted in complex arrangements with controlled gain-loss interplay. Here, we demonstrate anti-PT symmetry inherent in the nonlinear optical interaction based upon forward optical four-wave mixing in a laser-cooled atomic ensemble with negligible linear gain and loss. We observe that the pair of frequency modes undergo a nontrivial anti-PT phase transition between coherent power oscillation and optical parametric amplification in presence of a large phase mismatch.
Physical Review Letters
Digital Object Identifier (DOI)
Jiang, Yue; Mei, Yefeng; Zhai, Yanhua; and Wen, Jianming, "Anti-Parity-Time Symmetric Optical Four-Wave Mixing in Cold Atoms" (2019). Faculty Publications. 4472.