High-intensity interminiband terahertz emission from chirped superlattices

Electroluminescence at $\text{λ∼69\hspace{0.17em}μ}\mathrm{m}$ (4.3 THz) is reported from interminiband transitions in quantum-cascade structures with superlattice active regions. Spontaneous emission gives a low-temperature linewidth of 2 meV (0.48 THz) with linear light–current characteristics observed up to high-current densities $\text{(625\hspace{0.17em}}{\mathrm{A/cm}}^2\mathrm{),}$ resulting in record output powers of 500 pW. Devices operate up to above liquid-nitrogen temperature, with both emission wavelength and current–voltage characteristics in good agreement with theoretical predictions.