Title :
THz Difference-Frequency Generation in MOVPE-Grown Quantum Cascade Lasers
Author :
Vijayraghavan, Karun ; Min Jang ; Aiting Jiang ; Xiaojun Wang ; Troccoli, Mariano ; Belkin, Mikhail A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Texas, Austin, TX, USA
Abstract :
We report mass-producible room-temperature electrically-pumped THz sources based on intra-cavity difference-frequency generation in mid-infrared InGaAs/AlInAs/InP quantum cascade lasers. Devices are grown by a commercial foundry using metal organic vapor phase epitaxy. A dual-stack active region possessing giant optical nonlinearity for 3.5 THz generation and a non-collinear Cherenkov waveguide THz outcoupling scheme is employed. Fabry-Pérot devices provided broad emission in the 3-4 THz range with a peak power of 5 μW. Single color THz sources were processed using surface distributed feedback gratings to produce narrowband emission at 3.5 THz with nearly 40 μW of peak power and a mid-infrared-to-THz conversion efficiency of 0.36 mW/W2. To better understand the dynamics of the DFG process, time gated spectral measurements of the mid-infrared pumps were performed and simultaneous lasing over the duration of the applied bias pulse was observed, thereby resulting in efficient difference frequency generation.
Keywords :
III-V semiconductors; MOCVD; aluminium compounds; diffraction gratings; distributed feedback lasers; gallium compounds; indium compounds; infrared spectra; laser cavity resonators; laser feedback; optical frequency conversion; optical pumping; optical waveguides; quantum cascade lasers; semiconductor growth; terahertz wave generation; vapour phase epitaxial growth; DFG process; Fabry-Perot devices; InGaAs-AlInAs-InP; MOVPE-grown quantum cascade lasers; electrically-pumped terahertz sources; frequency 3 THz to 4 THz; intracavity difference-frequency generation; metal organic vapor phase epitaxy; midinfrared pumps; midinfrared quantum cascade lasers; midinfrared-to-terahertz conversion efficiency; noncollinear Cherenkov waveguide terahertz outcoupling scheme; optical nonlinearity; power 5 muW; room temperature; surface distributed feedback gratings; temperature 293 K to 298 K; terahertz difference-frequency generation; time gated spectral measurements; Epitaxial growth; Gratings; Indium phosphide; Nonlinear optics; Performance evaluation; Quantum cascade lasers; Terahertz sources; nonlinear optics; quantum cascade lasers; roomtemperature terahertz generation;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2013.2294941
