Ultimate lasing temperature of microdisk lasers

A model is developed that allows one to analytically determine the threshold current of a microdisk laser taking into account its self-heating as a function of the ambient temperature and the microlaser diameter. It is shown that there exists a minimal diameter of a microdisk caused by self-heating, up to which it is possible to achieve continuous-wave lasing at a given temperature. Another manifestation of self-heating effect is the existence of a maximum operating temperature, which is the lower the smaller the diameter of the microlaser. Reasonable agreement between the predictions of the model and the available experimental data is shown.