Bifurcations and Phase Transitions: Squeezing and lasing in lasers

Mark Carroll

University of Strathclyde -

There are three ways photons arrange themselves when they are emitted from a device; we develop a model that predicts all three. We consider a fully quantized model for N quantum dots (QDs) coupled to the modes of an optical cavity and we calculate analytically thresholds between different thermal, anti-bunching and lasing emission regimes. We find that the lasing regime is reached above a critical number of QDs via a transition from thermal emission to anti-bunching to lasing as the pump increases. The anti-bunching regime becomes vanishingly small in the control parameter space in the limit of large number of QDs. For any system size the bifurcation is generic and we observe the position of the laser threshold move to the inflection point of the input-output (I-O) curves; a phase transition occurs between the incoherent and coherent emission regimes as the macroscopic limit is reached.

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