Nonreciprocal photon transmission and amplification via reservoir engineering
The general desire to break reciprocity in engineered photonic structures has garnered an immense amount of recent interest. For example nonreciprocal microwave-frequency devices are crucial to efforts at quantum-information processing with superconducting circuits. We discuss a general method for constructing nonreciprocal, cavity-based photonic devices, based on matching a given coherent interaction with its corresponding dissipative counterpart; it generalizes the basic structure used in the theory of cascaded quantum systems. In contrast to interference-based schemes, our approach allows directional behaviour over a wide bandwidth. We show how it can be used to devise isolators and directional, quantum-limited ampliﬁers; of particular interest is a directional phase-sensitive ampliﬁer which is not limited by any fundamental gain-bandwidth constraint. Our approach is particularly well-suited to implementations using superconducting microwave circuits.
Host- Mohammad Hafezi