Standoff Detection of Oil and Powder Mixtures at 12 Meters Using a Tunable Quantum Cascade Laser-Based System with a Close Focus Telescope and Uncooled Infrared Detector

We have designed and demonstrated a quantum cascade laser (QCL) based standoff system that utilizes an uncooled mercury cadmium telluride (MCT) detector with lock-in signal processing for chemical identification at a distance of 12.5 meters in indoor ambient light conditions. In the system, a tunable quad-QCL operating (1 MHz) in quasi-continuous wave mode between 8.45 and 10.03 μm (∼1182 to 1000 cm−1) serves as the active mid-infrared source for remotely interrogating mineral, powder, and thin film oil samples including powder mixtures (6, 12.5, 25, and 50%) of crystalline quartz (SiO2) in KBr. Light as reflected from a given sample is collected using a 10-inch (25.4 cm) Dall Kirkham telescope and coupled with ZnSe optics to an uncooled MCT detector. The mixture dependence of the highly transparent KBr and strongly absorbing quartz was found to fit a modified version of the Schatz reflectance model for compacted powder mixtures. All reflectance spectra reported are relative to an Au-coated diffuse reflector. A NIST traceable polystyrene standard reflector was also used to determine the QCL wavelength tuning range and calibration.

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3.5 THz quantum-cascade laser emission from dual diagonal feedhorns

International Journal of Microwave and Wireless Technologies ◽

10.1017/s175907871900028x ◽

2019 ◽

Vol 11 (9) ◽

pp. 909-917 ◽

Cited By ~ 1

Author(s):

B. N. Ellison ◽

A. Valavanis ◽

O. Auriacombe ◽

D. Gerber ◽

T. Rawlings ◽

...

Keyword(s):

Quantum Cascade Laser ◽

Continuous Wave ◽

Wave Mode ◽

Substantial Improvement ◽

Quantum Cascade ◽

Novel Device ◽

Single Output ◽

Future Space ◽

Continuous Wave Mode ◽

Observation Space

AbstractAntenna-pattern measurements obtained from a double-metal supra-terahertz-frequency (supra-THz) quantum cascade laser (QCL) are presented. The QCL is mounted within a mechanically micro-machined waveguide cavity containing dual diagonal feedhorns. Operating in continuous-wave mode at 3.5 THz, and at an ambient temperature of ~60 K, QCL emission has been directed via the feedhorns to a supra-THz detector mounted on a multi-axis linear scanner. Comparison of simulated and measured far-field antenna patterns shows an excellent degree of correlation between beamwidth (full-width-half-maximum) and sidelobe content and a very substantial improvement when compared with unmounted devices. Additionally, a single output has been used to successfully illuminate and demonstrate an optical breadboard arrangement associated with a future supra-THz Earth observation space-borne payload. Our novel device has therefore provided a valuable demonstration of the effectiveness of supra-THz diagonal feedhorns and QCL devices for future space-borne ultra-high-frequency Earth-observing heterodyne radiometers.

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Ultralow power consumption of a quantum cascade laser operating in continuous-wave mode at room temperature

Optics Express ◽

10.1364/oe.405528 ◽

2020 ◽

Vol 28 (24) ◽

pp. 36497

Author(s):

Fengmin Cheng ◽

Jinchuan Zhang ◽

Yanjiao Guan ◽

Pengchang Yang ◽

Ning Zhuo ◽

...

Keyword(s):

Power Consumption ◽

Quantum Cascade Laser ◽

Room Temperature ◽

Continuous Wave ◽

Wave Mode ◽

Quantum Cascade ◽

Continuous Wave Mode ◽

Ultralow Power

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High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

AIP Advances ◽

10.1063/1.4959195 ◽

2016 ◽

Vol 6 (7) ◽

pp. 075210 ◽

Cited By ~ 33

Author(s):

Xuemin Wang ◽

Changle Shen ◽

Tao Jiang ◽

Zhiqiang Zhan ◽

Qinghua Deng ◽

...

Keyword(s):

High Power ◽

Continuous Wave ◽

Quantum Cascade Lasers ◽

Wave Mode ◽

Quantum Cascade ◽

Continuous Wave Mode ◽

Cascade Lasers

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Repetition frequency locking of a terahertz quantum cascade laser emitting at 4.2 THz

Terahertz Science and Technology ◽

10.1051/tst/2020131032 ◽

2020 ◽

Vol 13 (1) ◽

pp. 32-40

Author(s):

Wen Guan ◽

Ziping Li ◽

Kang Zhou ◽

Wenjian Wan ◽

Xiaoyu Liao ◽

...

Keyword(s):

Quantum Cascade Laser ◽

Continuous Wave ◽

Frequency Comb ◽

Signal To Noise Ratio ◽

Phase Lock Loop ◽

Wave Mode ◽

Repetition Frequency ◽

Frequency Locking ◽

Frequency Combs ◽

Quantum Cascade

The electrically-pumped terahertz quantum cascade laser (QCL) is characterized by high power emission, compact, broad frequency coverage, and so on, which shows abilities for frequency comb operations. Although free-running QCLs can work as frequency combs by designing the laser structure with small group velocity dispersions and/or inserting mirrors to compensate laser intrinsic dispersions, the ideal comb operation can only be obtained by firmly locking the repetition frequency and carrier frequency of a laser. In this work, we have reported a repetition frequency locking of a terahertz QCL emitting around 4.2 THz. When the 6-mm-long laser is operated in continuous wave mode without any locking techniques, the repetition frequency is measured to be ~6.15 GHz with a linewidth of hundred kilohertz. Once a phase lock loop (PLL) is applied to dynamically control the drive current of the QCL, we have demonstrated a successful repetition frequency locking of the laser with a signal to noise ratio of 80 dB. This technique can be employed for the frequency comb and dual-comb operations of terahertz QCLs for high-resolution applications.

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