Table 2. Key design and operation parameters of previously reported terahertz QCLs based on three-well resonant-phonon design scheme (all listed QCLs are in the GaAs/Al_0.15Ga_0.85As material-system).

Reference	ν	Δinj (meV)	Δcol (meV)	fosc	Tmax	Jth
Ref. 21	3.0 THz	1.8 meV	3.8 meV	0.86	178 K	700 A/cm2 (78 K)
Ref. 20	3.8 THz	2.2 meV	4.8 meV	0.38	186 K	410 A/cm2 (5 K)
Ref. 22	3.1 THz	1.8 meV	3.9 meV	0.85	170 K	700 A/cm2 (10 K)
Ref. 3	3.1 THz	1.7 meV	3.9 meV	0.57	200 K	970 A/cm2 (8 K)
Ref. 23	4.0 THz	2.5 meV	4.1 meV	0.37	151 K	680 A/cm2 (5 K)

QCLs emitting in the range of ~3–4 THz with T_max > 150 K are listed in chronological order of publication. Δ_inj is the energy splitting (anticrossing) at injection resonance, Δ_col is the corresponding value for extraction resonance, and f_osc represents the normalized radiative oscillator-strength at design bias.