Dependence of lasing threshold on Q factor in a deformed microcavity laser

The relationship between lasing threshold and quality (Q) factor is investigated. When a deformed microcavity laser composed of a circular arc and an isosceles trapezoid is excited by current injection, various modes lase in ten emission directions. The lasing modes are classified into four groups, and the lasing threshold of each mode group is obtained according to emission spectra. The Q factor of each mode group is obtained from the resonance by comparing the far-field patterns of resonances with those of mode groups. Through the study, we find that the lasing threshold strongly depends on the Q factor.