Temperature Dependence of the Spontaneous Emission Factor in Subwavelength Semiconductor Lasers

We perform a rigorous analysis of the temperature dependence of the spontaneous emission factor, beta, in subwavelength semiconductor lasers. The analysis combines a recent formulation of the Purcell effect in semiconductor nanolasers with finite-element modeling and established theoretical models for temperature-dependent emission spectra. While the method is general, we apply it to a subwavelength metallo-dielectric nanolaser, and find that beta of the dominant mode decreases sharply below a transition temperature. This result is found for both positive and negative thermo-optic coefficients of the semiconductor material, and occurs because of detuning between the dominant mode and peak emission. The analysis enables better understanding of nanolaser dynamics, as well as the design and characterization of high-beta nanolasers.