A two-mode squeezed light based on a double-pump phase-matching geometry**Project supported by the National Natural Science Foundation of China (Grant Nos. 11974111, 11474095, 11874152, 11604069, 91536114, 11654005, and 11234003), the Fundamental Research Funds for the Central Universities, China, the Science Foundation of Shanghai, China (Grant No. 17ZR1442800), and the National Key Research and Development Program of China (Grant No. 2016YFA0302001).

Abstract

We theoretically investigate the frequency-nondegenerate and frequency degenerate squeezed lights with a four-wave mixing process (4WM) driven by two pump fields crossing at a small angle. Different from a 4WM process driven by a single pump field, the refractive index of the corresponding probe field, np, can be converted to a value that is greater than 1 or less than 1 by an angle adjustment. In the new region with np < 1, the bandwidth of the gain is relatively large due to the slow change in the refractive index with the two-photon detuning. In this region with an exchange of the roles of the pump and probe beams, the frequency degenerate and spatial nondegenerate twin beams can be generated, which has potential application in quantum information and quantum metrology.