Two-dimensional broadband distributed-feedback quantum cascade laser arrays

Jung

Applied Physics Letters

et al. 2015

We demonstrate a compact monolithic terahertz source continuously tunable from 1.9 THz to 3.9 THz with the maximum peak power output of 106 μW at 3.46 THz at room temperature. The source consists of an array of 10 electrically tunable quantum cascade lasers with intra-cavity terahertz difference-frequency generation. To increase fabrication yield and achieve high THz peak power output in our devices, a dual-section current pumping scheme is implemented using two electrically isolated grating sections to independently control gain for the two mid-IR pumps.

mentioning

confidence: 98%

Widely tunable terahertz source based on intra-cavity frequency mixing in quantum cascade laser arrays

Jung

Applied Physics Letters

et al. 2015

“…However, the operation was limited by variation in output power between the individual QCLs, which was attributed to the influence of device facet on mode selection. Although the ring-cavity configuration without facets can eliminate their influence on mode selection and output power, the DFB ring-cavity surface emitting QCL arrays also face a series of disadvantages, including large-size induced beam combing challenge, minimum-centre intensity distribution [22] and low output power [23]. Besides, master-oscillator power-amplifiers [24] and wavelength beam combining approaches [25] have also been used to obtain broad spectral tenability and low beam divergence based on multi-wavelength QCL arrays.…”

Section: Brief Review Of Qcl Arraysmentioning

confidence: 99%

Power Amplification and Coherent Combination Techniques for Terahertz Quantum Cascade Lasers

Xie¹,

Li²,

Wang³

et al. 2017

Quantum Cascade Lasers

Power amplification and coherent combination are important ways to improve the output power and beam quality of single-mode terahertz quantum cascade lasers (THz QCLs). Up to date, the tapered waveguide is the most convenient way to amplify the power of THz QCLs. The self-focusing effect in tapered THz QCLs induces nonmonotonic behaviours of the peak power and far-field beam divergence, which lead to the existence of optimal structural parameters. The surface and lateral grating techniques have also been employed in tapered THz QCLs to further improve the spectral purity. For coherent combinations, the progress of facet-emitting phase-locked arrays of THz QCLs is still limited due to both the lack of the understanding of dynamics of coupled QCLs and the difficulties in designing high-performance coupled waveguides. We will briefly review the developments of coherent arrays of THz QCLs and present a design of monolithic QCL arrays with common coupled cavity to achieve the optical mutual injection, which may provide a new way for coherent combination of THz QCLs.

“…An array of lasers arranged side by side can operate with completely isolated lasing cavities. However, it suffers from spatial separation of the light sources, and requires an external beam combination scheme [43][44][45]. Although such arrays can be operational, the spectroscopic requirements for low concentration gas sensing are very stringent and are best implemented with a single source coupled into an amplifier (e.g., a multi-pass interaction cell [46,47]).…”

Section: Qcl Arraysmentioning

confidence: 99%

Advanced Fabrication of Single-Mode and Multi-Wavelength MIR-QCLs

et al. 2016

Abstract:In this article we present our latest work on the optimization of mid-infrared quantum cascade laser fabrication techniques. Our efforts are focused on low dissipation devices, broad-area high-power photonic crystal lasers, as well as multi-wavelength devices realized either as arrays or multi-section distributed feedback (DFB) devices. We summarize our latest achievements and update them with our most recent results.