Experimental observation of lasing shutdown via asymmetric gain

Chitsazi, Mahboobeh; Factor, Samuel M.; Schindler, Joseph; Ramezani, Hamidreza; Ellis, F. M.

doi:10.1103/physreva.89.043842

Cited by 29 publications

(21 citation statements)

References 19 publications

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“…In recent years, a much more efficient approach named steady state ab initio lasing theory (SALT) has emerged, which can be used to describe the steady-state lasing of lasers [17][18][19][20][21][22][23]. Among other advances, this new framework has shed light on weakly-scattering random lasers [24], on pump-induced exceptional points [11,12,25,26] and on coherent perfect absorption [27,28] and has opened up new ways of controlling the emission patterns of random as well as of microcavity lasers [29,30]. One of the major drawbacks of SALT is that its conventional formulation fails for the simulation of microlasers with nearly degenerate modes as occurring, e.g., in whispering gallery mode resonators with an inherent symmetry [2,6,8,10,12,31].…”

Section: Introductionmentioning

confidence: 99%

Steady-stateab initiolaser theory for fully or nearly degenerate cavity modes

et al. 2015

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We investigate the range of validity of the recently developed steady-state ab-initio laser theory (SALT). While very efficient in describing various microlasers, SALT is conventionally believed not to be applicable to lasers featuring fully or nearly degenerate pairs of resonator modes above the lasing threshold. Here we demonstrate how SALT can indeed be extended to describe such cases as well, with the effect that we significantly broaden the theory's scope. In particular, we show how to use SALT in conjunction with a linear stability analysis to obtain stable single-mode lasing solutions that involve a degenerate mode pair. Our flexible and efficient approach is tested on one-dimensional ring lasers as well as on two-dimensional microdisk lasers with broken symmetry.

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Section: Introductionmentioning

confidence: 99%

Steady-stateab initiolaser theory for fully or nearly degenerate cavity modes

et al. 2015

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“…The exceptional points (EPs), observed in the non-Hermitian parity–time (PT)-symmetric physical systems that possess multi-well potentials of energy gain or loss1234567891011121314, have been recently explored in coupled optical cavities consisting of two identical micrometre-sized cavities, by controlling intercavity coupling and asymmetric gain or loss1516171819. For example, EPs and unidirectional light transmission were measured in active and passive silica microtoroids coupled to tapered fibres, where the intercavity coupling was tuned1516.…”

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confidence: 99%

Direct observation of exceptional points in coupled photonic-crystal lasers with asymmetric optical gains

et al. 2016

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Although counter-intuitive features have been observed in non-Hermitian optical systems based on micrometre-sized cavities, the achievement of a simplified but unambiguous approach to enable the efficient access of exceptional points (EPs) and the phase transition to desired lasing modes remains a challenge, particularly in wavelength-scale coupled cavities. Here, we demonstrate coupled photonic-crystal (PhC) nanolasers with asymmetric optical gains, and observe the phase transition of lasing modes at EPs through tuning of the area of graphene cover on one PhC cavity and systematic scanning photoluminescence measurements. As the gain contrast between the two identical PhC cavities exceeds the intercavity coupling, the phase transition occurs from the bonding/anti-bonding lasing modes to the single-amplifying lasing mode, which is confirmed by the experimental measurement of the mode images and the theoretical modelling of coupled cavities with asymmetric gains. In addition, we demonstrate active tuning of EPs by controlling the optical loss of graphene through electrical gating.

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“…Synthetic photonic structures with anti-linear symmetries have attracted a lot of attention during the last five years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Due to the presence of appropriately tailored amplification and attenuation elements, they are described by non-Hermitian mathematical models which violate the time reversal symmetry  .…”

Section: Introductionmentioning

confidence: 99%

Four-port photonic structures with mirror-time reversal symmetries

Thomas

Ellis

2016

New J. Phys.

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We investigate the transport characteristics of a four-port gyrotropic photonic structure with mirror-time reversal symmetry. The structure consists of two coupled cavities with balanced amplification and attenuation. The cavities are placed on top of a gyrotropic substrate and are coupled to two bus waveguides. Using detail simulations in the microwave domain we demonstrate a strong non-reciprocal intra-guide port transport and an enhanced inter-guide port transmittance. The non-reciprocal features are dramatically amplified in the gain-loss parameter domain where an exceptional point degeneracy, for the associated isolated set-up, occurs. These results are explained theoretically in terms of an equivalent lumped circuit.

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Experimental observation of lasing shutdown via asymmetric gain

Cited by 29 publications

References 19 publications

Steady-stateab initiolaser theory for fully or nearly degenerate cavity modes

Steady-stateab initiolaser theory for fully or nearly degenerate cavity modes

Direct observation of exceptional points in coupled photonic-crystal lasers with asymmetric optical gains

Four-port photonic structures with mirror-time reversal symmetries

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