Quantum field states in nonlinear optical balance

James J. Wynne

In the presence of resonant multiphoton excitation, experimental observations of photoionization, fluorescence, and amplified spontaneous emission have shown suppression of these effects.1 There is a common mechanism tying these phenomena together. All these processes involve the coherent nonlinear coupling of two or more optical waves via a dissipative nonlinear optical medium. Independent of initial conditions, as these waves propagate through the nonlinear medium, they develop amplitudes and relative phases that minimize the dissipative losses. The condition of minimum loss is one in which the excitation of the nonlinear medium is reduced due to the waves being in a state of nonlinear optical balance. This balance is stabilized by the dissipation. Other combinations of amplitude and phase are more lossy and rapidly damped out.

Robert W. Boyd

Rakesh Kumar

Hongjian Luo, J. Guan, Chengjie Zhu +2 more

The realization of ultra-low-noise quantum phase gates and squeezed state rotations has long been a goal in the fields of quantum optics and quantum information. In this study, we present a theoretical proposal for an ultra-low-noise quantum phase gate and squeezed state rotation using a coherently prepared atomic medium. We demonstrate that, under a suitable set of parameters, the loss and gain mechanisms within this coherently prepared atomic system can balance each other over a broad range of probe field frequencies. As a result, the noise associated with the Raman gain process can be significantly suppressed within this frequency range. Additionally, we show that the system exhibits a strong optical Kerr nonlinearity, which can facilitate a π -phase gate operation for the probe field at the quantum level with high fidelity. Furthermore, when a squeezed probe field is injected, the squeezed state of the input nonclassical field can undergo a rotation. These findings provide valuable insights into the unique properties of gain-and-loss-balanced coherently prepared atomic media, paving the way for new applications in quantum information processing and quantum metrology.

Y. R. Shen

Ai-Xi Chen, Xu Yan-Qiu, Li Deng +1 more

This paper investigates the nonlinear evolution of the pulse probe field in an asymmetric coupled-quantum well driven coherently by a pulse probe field and two controlled fields. This study shows that, by choosing appropriate physical parameters, self-modulation can precisely balance group velocity dispersion in the investigated system, leading to the formation of ultraslow optical solitons of the probe field. The proposed scheme may lead to the development of the controlled technique of optical buffers and optical delay lines.