S. Krishna et al., Room-temperature long-wavelength (lambda=13.3 mu m) unipolar quantum dot intersubband laser, ELECTR LETT, 36(18), 2000, pp. 1550-1551
Long-wavelength (lambda = 13.3 mu m) unipolar lasing at 283 K from self-org
anised In0.4Ga0.6As/GaAs quantum dots. due to intersubband transitions in t
he conduction band, is demonstrated for the first time. The threshold curre
nt density under continuous wave operation is 1.1 kA/cm(2) for a 60 mu m x
1.2 mm broad-area plasmon-enhanced waveguide device and the maximum power o
utput is similar or equal to 1 mu W. The longs intersubband relaxation time
in quantum dots, together with the short lifetime in the ground state, due
to interband stimulated emission. help to achieve the necessary population
inversion and gain.