Loss-induced suppression and revival of lasing

By Bo Peng, Ş. Özdemir, S. Rotter, H. Yılmaz, M. Liertzer, Faraz Monifi, C. Bender, Franco Nori, Lan Yang. Science, 2014

952 citations recorded by the source corpus.

Controlling and reversing the effects of loss are major challenges in optical systems. For lasers, losses need to be overcome by a sufficient amount of gain to reach the lasing threshold. In this work, we show how to turn losses into gain by steering the parameters of a system to the vicinity of an exceptional point (EP), which occurs when the eigenvalues and the corresponding eigenstates of a system coalesce. In our system of coupled microresonators, EPs are manifested as the loss-induced suppression and revival of lasing. Below a critical value, adding loss annihilates an existing Raman laser. Beyond this critical threshold, lasing recovers despite the increasing loss, in stark contrast to what would be expected from conventional laser theory. Our results exemplify the counterintuitive features of EPs and present an innovative method for reversing the effect of loss. Introducing loss into a coupled optical system can result in an enhancement of the optical properties. [Also see Perspective by Schwefel] Achieving gain despite increasing loss When energy is pumped into an optically active material, the buildup (or gain) of excitations within the material can reach a critical point where the emission of coherent light, or lasing, can occur. In many systems, however, the buildup of the excitations is suppressed by losses within the material. Overturning conventional wisdom that loss is bad and should be minimized, Peng et al. show that carefully tweaking the coupling strength between the various components of a coupled optical system can actually result in an enhancement of the optical properties by adding more loss into the system (see the Perspective by Schwefel). The results may provide a clever design approach to counteract loss in optical devices. Science, this issue p. 328; see also p. 304

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/6dedabc3997ba7ac34ae5735f6bc97986c86dbbb

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Citations in the corpus

Nonlinear waves in PT -symmetric systems (2016, methodology): “Experimental implementations of PT -symmetric micro-cavities were reported by Peng et al. (2014a) and Chang et al. (2014).”
Experimental realization of a Weyl exceptional ring (2018, background): “This effect can be viewed as the result of an impedance mismatch between the different sublattices of the system due to the spatially inhomogeneous loss, and can lead to loss-induced transmission in waveguides [67] and reverse pump dependence in lasers [43, 70, 71].”
Nonlinear photonics with high-Q whispering-gallery-mode resonators (2017, methodology): “It has also been used in studying a non-Hermitian system composed of two coupled microtoroid resonators for its lasing behavior in the vicinity of an exceptional point [249].”
Quantum exceptional points of non-Hermitian Hamiltonians and Liouvillians: The effects of quantum jumps (2019, neutral): “, [5, 32]).”