Real-time terahertz imaging over a standoff distance (>25meters)

  title={Real-time terahertz imaging over a standoff distance (>25meters)},
  author={Alan Wei Min Lee and Qi Qin and Sushil Kumar and Benjamin S. Williams and Q. Y. Hu and John Louis Reno},
  journal={Applied Physics Letters},
The authors demonstrate the use of a terahertz quantum cascade laser (QCL) for real-time imaging in transmission mode at a standoff distance of 25meters. Lasing frequency was selected for optimum transmission within an atmospheric window at ∼4.9THz. Coarse frequency selection was made by design of the QCL gain medium. Finer selection (to within 0.1THz) was made by judicious choice of laser cavity length to adjust facet losses and therefore lasing threshold bias, in order to overlap the peak… 

Figures from this paper

Terahertz imaging with room-temperature terahertz difference-frequency quantum-cascade laser sources.
High-quality non-destructive imaging using a broadband terahertz quantum cascade laser source based on Cerenkov difference-frequency generation is demonstrated, achieving well-resolved, high-contrast images of objects obscured by opaque materials.
Real-Time Imaging Using a High-Power Monochromatic Terahertz Source: Comparative Description of Imaging Techniques with Examples of Application
Gradually appearing high-power terahertz sources require the development of adequate imaging techniques. This paper describes four imaging techniques (with a thermal recorder, temperature-sensitive
Imaging with a 90 frames/s microbolometer focal plane array and high-power terahertz free electron laser
An uncooled microbolometer focal plane array (FPA) has been developed and used for imaging of objects illuminated by monochromatic coherent radiation of a free electron laser tunable in the range of
Terahertz imaging through self-mixing in a quantum cascade laser.
Self-mixing imaging offers high sensitivity, a potentially fast response, and a simple, compact optical design, and it is shown that it can be used to obtain high-resolution reflection images of exemplar structures.
Cavity-based photoconductive sources for real-time terahertz imaging
Optically driven photoconductive switches are one of the predominant sources currently used in terahertz imaging systems. However, owing to their low average powers, only raster-based images can be
Coherent three-dimensional terahertz imaging through self-mixing in a quantum cascade laser
We demonstrate coherent terahertz (THz) frequency imaging using the self-mixing effect in a quantum cascade laser (QCL). Self-mixing voltage waveforms are acquired at each pixel of a two-dimensional
Stand-alone system for high-resolution, real-time terahertz imaging.
This work presents a stand-alone, portable system for high resolution real-time THz imaging using a quantum cascade laser emitting at 3.4 THz laser based on a third-order distributed feedback cavity as source.
Portable real-time THz imaging setup based on QC lasers
A portable, stand-alone, real-time THz imaging system for high resolution is presented. The total weight of the apparatus is less than 15 kg and its physical dimension is of approximately (65 cm)3. A
Continuous-wave coherent imaging with terahertz quantum cascade lasers using electro-optic harmonic sampling
We demonstrate a coherent imaging system based on a terahertz (THz) frequency quantum cascade laser (QCL) phase-locked to a near-infrared fs-laser comb. The phase locking enables coherent


Real-time imaging using a 4.3-THz quantum cascade laser and a 320 /spl times/ 240 microbolometer focal-plane array
We report the use of a ~50-mW peak power 4.3-THz quantum cascade laser (QCL) as an illumination source for real-time imaging with a 320 times 240 element room-temperature microbolometer focal-plane
Imaging with terahertz waves.
This work presents what is to their knowledge the first imaging system based on optoelectronic terahertz time-domain spectroscopy, and demonstrates applications to package inspection and chemical content mapping in biological objects.
Low-cost uncooled microbolometer imaging system for dual use
Loral Infrared & Imaging Systems is developing low cost, high performance uncooled infrared imaging products for both military and commercial applications. These products are based on the
Terahertz imaging of subjects with concealed weapons
In response to the growing interest in developing terahertz imaging systems for concealed weapons detection, the Submillimeter-Wave Technology Laboratory (STL) at the University of Massachusetts
High-power terahertz quantum cascade lasers
We report the demonstration of quantum-cascade lasers at ~4.4 THz (lambda ~ 68 mum) that emit 248 mW peak power in pulsed mode, and 138 mW continuous-wave power at heat-sink temperatures of 10 K.
Resonant-phonon-assisted THz quantum-cascade lasers with metal–metal waveguides
We report our development of terahertz (THz) quantum-cascade lasers (QCLs) based on two novel features. First, the depopulation of the lower radiative level is achieved through resonant longitudinal
Resonant tunneling in quantum cascade lasers
Experimental evidence that in quantum cascade lasers electron injection into the active region is controlled by resonant tunneling between two-dimensional subbands is discussed. A quantitative
Terahertz Imaging For Drug Detection And Large-Scale Integrated Circuit Inspection
Until fairly recently, the terahertz range was considered little more than the dark gap that separated the two halves of the electromagnetic spectrum. Now scientists have come to view it as a bridge
Security applications of terahertz technology
Recent events have accelerated the quest for ever more effective security screening to detect an increasing variety of threats. Many techniques employing different parts of the electromagnetic
Terahertz quantum-well photodetector
The design and projected performance of quantum-well infrared photodetectors (QWIP) for the terahertz (1–10 THz) or the very-far-infrared region are presented together with our initial demonstration