Threshold current reduction and directional emission of deformed microdisk lasers via spatially selective electrical pumping

We report on laser threshold current reduction and directional emission from quadrupole-shaped AlGaInAs microdisk diode lasers by selective electrical pumping. The directional emission results from breaking the 2-fold rotation symmetry of the system by the introduction of a triangle-shaped contact geometry, and the laser threshold reduction results from a small current injection area. Room temperature laser operation is achieved in both pulsed and continuous-wave operation for a microdisk radius of 50 μm and deformation constant of e = 0.09, with optical output power of more than 8 mW and 3 mW, respectively. Under pulsed operation, the minimum measured threshold current for selectively pumped microlasers is 42 mA, significantly lower than the minimum measured threshold current for uniformly pumped microlasers (58 mA) and standard ridge lasers (80 mA) of the same device size and material.