Recent Advances in Room Temperature, High-Power Terahertz Quantum Cascade Laser Sources Based on Difference-Frequency Generation

Abstract

We present the current status of high-performance, compact, THz sources based on intracavity nonlinear frequency generation in mid-infrared quantum cascade lasers. Significant performance improvements of our THz sources in the power and wall plug efficiency are achieved by systematic optimizing the device's active region, waveguide, and chip bonding strategy. High THz power up to 1.9 mW and 0.014 mW for pulsed mode and continuous wave operations at room temperature are demonstrated, respectively. Even higher power and efficiency are envisioned based on enhancements in outcoupling efficiency and mid-IR performance. Our compact THz device with high power and wide tuning range is highly suitable for imaging, sensing, spectroscopy, medical diagnosis, and many other applications.

QCL-based frequency metrology from the mid-infrared to the THz range: a review

“…However, RT operation is highly desired for applications and would largely simplify any experimental setup. To address the need for RT THz sources, an alternative approach has been implemented on the basis of intracavity difference-frequency generation (DFG) in mid-IR QCLs [137][138][139]. With the introduction of a Cherenkov phasematching scheme for efficient THz extraction [140,141], THz DFG-QCLs have made marked progress in the past 5 years [142,143].…”

Photonic Engineering Technology for the Development of Terahertz Quantum Cascade Lasers

“…[9] Since then, continuous efforts of designing various THz QCL active regions have been devoted to improving the performance, which was comprehensively reviewed in the literature. [24] Many other material systems like InGaAs/GaAsSb, [25] InGaAs/InAlAs, [26] InGaAs/ AlInGaAs, [27] and Ge/SiGe heterostructures [28][29][30] have also been proposed to achieve better temperature performance, but the understanding of the material properties and the material growth technologies is still in infancy. 8-5.4 THz.…”

Гетероструктуры Одночастотных И Двухчастотных Квантово-Каскадных Лазеров

“…Для генерации на РЧ, во-первых, необходимы высокие выходные оптические мощности излучения на частотах f 1 и f 2 в среднем ИК-диапазоне, а также повышенная величина нелинейной восприимчи-вости второго порядка (χ (2) ) [18,19]. Повышение коэффи-циента χ (2) возможно за счет уменьшения толщины вы-ходного барьера-инжектора [18] в конструкции активной области с двухфононной релаксацией электронов [20], а также путем применения конструкций активной области на основе однофононного опустошения нижнего уров-ня [18], переходов " связанное состояние -непрерывный спектр" [21], с двумя верхними уровнями [22].…”