Exceptional Points as Lasing Prethresholds

Zyablovsky, A. A.; Doronin, I. V.; Andrianov, E. S.; Pukhov, A.; Lozovik, Yurii E.; Виноградов, А. П.; Lisyansky, A. A.

doi:10.1002/lpor.202000450

Cited by 17 publications

(6 citation statements)

References 66 publications

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“…[19] EPs can enhance lasing emission and allow to control the lasing directivity. [18,20,21] Recently, it was also shown that EPs provide the enhanced local density of the states (LDOS), scaling with a square of the Purcell factor. [22,23] If EPs appear on a polariton branch, this causes a strong enhancement of the boson scattering probability to this state, which can lead to the polariton accumulation in a nonlinear regime, resulting in the polariton lasing.…”

Section: Introductionmentioning

confidence: 99%

Room‐Temperature Exceptional‐Point‐Driven Polariton Lasing from Perovskite Metasurface

Masharin

Samusev

Bogdanov

et al. 2023

Adv Funct Materials

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Excitons in lead bromide perovskites exhibit high binding energy and high oscillator strength, allowing for a strong light‐matter coupling regime in the perovskite‐based cavities localizing photons at the nanoscale. This opens up the way for the realization of exciton‐polariton Bose–Einstein condensation and polariton lasing at room temperature – the inversion‐free low‐threshold stimulated emission. However, polariton lasing in perovskite planar photon cavities without Bragg mirrors has not yet been observed and proved experimentally. In this study, perovskite metasurface is employed, fabricated with nanoimprint lithography, supporting so‐called exceptional points to demonstrate the room‐temperature polariton lasing. The exceptional points in exciton‐polariton dispersion of the metasurface appear upon optically pumping in the nonlinear regime in the spectral vicinity of a symmetry‐protected bound state in the continuum providing high mode confinement with the enhanced local density of states beneficial for polariton condensation. The observed lasing emission possesses high directivity with a divergence angle of 1° over one axis. The employed nanoimprinting approach for solution‐processable large‐scale polariton lasers is compatible with various planar photonic platforms suitable for on‐chip integration.

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Section: Introductionmentioning

confidence: 99%

Room‐Temperature Exceptional‐Point‐Driven Polariton Lasing from Perovskite Metasurface

Masharin

Samusev

Bogdanov

et al. 2023

Adv Funct Materials

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“…In these systems, the EP separates areas of parameter space with PT-symmetric and non-PT-symmetric eigenstates 4 – 7 . Other examples of non-Hermitian systems with an EP include strongly coupled cavity-atom systems 3 , 8 , polariton systems 9 – 11 , two dimensional lattice systems 12 , 13 , optomechanical systems 14 , 15 , and even conventional laser systems 16 . Non-Hermitian systems with EPs have a number of unique properties, due to which they have found many applications 3 , 4 , 6 , 7 .…”

Section: Introductionmentioning

confidence: 99%

A new type of non-Hermitian phase transition in open systems far from thermal equilibrium

Sergeev

Zyablovsky

Andrianov

et al. 2021

Sci Rep

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We demonstrate a new type of non-Hermitian phase transition in open systems far from thermal equilibrium, which can have place in the absence of an exceptional point. This transition takes place in coupled systems interacting with reservoirs at different temperatures. We show that the spectrum of energy flow through the system caused by the temperature gradient is determined by the $$\varphi^{4}$$ φ 4 -potential. Meanwhile, the frequency of the maximum in the spectrum plays the role of the order parameter. The phase transition manifests itself in the frequency splitting of the spectrum of energy flow at a critical point, the value of which is determined by the relaxation rates and the coupling strength. Near the critical point, fluctuations of the order parameter diverge according to a power law with the critical exponent that depends only on the ratio of reservoirs temperatures. The phase transition at the critical point has the non-equilibrium nature and leads to the change in the energy flow between the reservoirs. Our results pave the way to manipulate the heat energy transfer in the coupled out-of-equilibrium systems.

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“…The systems in the state close to the EP demonstrate enhanced sensitivity to external perturbations and thus can be used for the EP-based sensors [18][19][20] and laser gyroscopes [21,22]. The EPs can be associated with the laser threshold [23,24] and find use in realization of specific lasing conditions [25][26][27]. Besides the isolated EPs, some non-Hermitian systems support the lines of EPs [28] or even the exceptional surfaces [29] which can be utilized for sensitivity enhancement as well [30,31].…”

Section: Introductionmentioning

confidence: 99%

Multimode -symmetry thresholds and third-order exceptional points in coupled dielectric waveguides with loss and gain

Hlushchenko¹,

Novitsky²,

Shcherbinin³

et al. 2021

J. Opt.

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A pair of coupled dielectric waveguides with balanced loss and gain is the basic system for observing the phenomena of parity-time ( ) symmetry and exceptional points (EPs). We use the multimode analytical approach to study the peculiarities of interaction between the modes excited in such an archetypal structure. With this approach, the conditions for symmetry breaking are obtained in the special case of the hybrid HE and EH modes resulting in the ordinary second-order EPs (or -symmetry thresholds). The coupling of modes with the different azimuthal indices (the TM01 and HE21 modes in our study) generates the uncommon types of EPs. First, there are the so-called multimode -symmetry thresholds due to interaction of hybrid and transverse modes. Second, the third-order EPs appear as a result of three-modes degeneracy of real eigenvalues. It is noteworthy that an increase in the EPs order is achieved without both breaking the symmetry and introducing additional elements into the waveguide structure. The results obtained with the multimode analytical approach are in perfect agreement with the independent full-wave simulations.

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Exceptional Points as Lasing Prethresholds

Cited by 17 publications

References 66 publications

Room‐Temperature Exceptional‐Point‐Driven Polariton Lasing from Perovskite Metasurface

Room‐Temperature Exceptional‐Point‐Driven Polariton Lasing from Perovskite Metasurface

A new type of non-Hermitian phase transition in open systems far from thermal equilibrium

Multimode -symmetry thresholds and third-order exceptional points in coupled dielectric waveguides with loss and gain

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