Detection of 3.4 THz radiation from a quantum cascade laser using a microbolometer infrared camera

Behnken, Barry N.; Lowe, Michele; Karunasiri, Gamani; Chamberlain, Danielle; Robrish, P. R.; Faist, Jérôme

doi:10.1117/12.719744

Cited by 15 publications

(15 citation statements)

References 12 publications

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“…[1][2][3][4][5] Unfortunately, background THz emission at 300 K is minute compared to shorter wavelength infrared (IR) radiation, and uncooled imaging in this spectral range is done either in transmission or reflection mode using a THz illuminating source. [1][2][3][6][7][8] Uncooled microbolometers optimized for 8 to 12-μm IR radiation coupled with THz quantum cascade lasers (QCLs) have been shown to be an effective imaging system. [6][7][8] Uncooled IR microbolometers generally have a noise equivalent power (NEP) in the THz range of approximately 300 pW∕Hz 1∕2 in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][6][7][8] Uncooled microbolometers optimized for 8 to 12-μm IR radiation coupled with THz quantum cascade lasers (QCLs) have been shown to be an effective imaging system. [6][7][8] Uncooled IR microbolometers generally have a noise equivalent power (NEP) in the THz range of approximately 300 pW∕Hz 1∕2 in Ref. 9 compared to a NEP of 14 pW∕Hz 1∕2 for the IR range 10 implying low responsivity at THz frequencies.…”

Section: Introductionmentioning

confidence: 99%

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Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

et al. 2013

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Abstract. To increase the sensitivity of uncooled thermal sensors in the terahertz (THz) spectral range (1 to 10 THz), we investigated thin metamaterial layers exhibiting resonant absorption in this region. These metamaterial films are comprised of periodic arrays of aluminum (Al) squares and an Al ground plane separated by a thin silicon-rich silicon oxide (SiO x ) dielectric film. These standard MEMS materials are also suitable for fabrication of bi-material and microbolometer thermal sensors. Using SiO x instead of SiO 2 reduced the residual stress of the metamaterial film. Finite element simulations were performed to establish the design criteria for very thin films with high absorption and spectral tunability. Single-band structures with varying SiO x thicknesses, square size, and periodicity were fabricated and found to absorb nearly 100% at the designed frequencies between three and eight THz. Multiband absorbing structures were fabricated with two or three distinct peaks or a single-broad absorption band. Experimental results indicate that is possible to design very efficient thin THz absorbing films to match specific applications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

et al. 2013

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“…More recently, the potential use of uncooled microbolometer cameras for THz imaging using quantum cascade laser (QCL) sources have been reported. [10][11][12][13] In this paper, we report on the successful use of an uncooled microbolometer infrared camera to image radiation produced by a 3.6-THz QCL with an average output power of 1 mW. Single frame and video recordings of the imaging trials are presented.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a 3.6-THz quantum cascade laser for real-time imaging with a microbolometer focal plane array

et al. 2008

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Real-time imaging in the terahertz (THz) spectral range was achieved using a 3.6-THz quantum cascade laser (QCL) and an uncooled, 160x120 pixel microbolometer camera fitted with a picarin lens. Noise equivalent temperature difference of the camera in the 1-5 THz frequency range was calculated to be at least 3 K, confirming the need for external THz illumination when imaging in this frequency regime. After evaluating the effects of various operating parameters on laser performance, the QCL found to perform optimally at 1.9 A in pulsed mode with a 300 kHz repetition rate and 10-20% duty cycle; average output power was approximately 1 mW. Under this scheme, a series of metallic objects were imaged while wrapped in various obscurants. Single-frame and extended video recordings demonstrate strong contrast between metallic materials and those of plastic, cloth, and paper-supporting the viability of this imaging technology in security screening applications. Thermal effects arising from Joule heating of the laser were found to be the dominant issue affecting output power and image quality; these effects were mitigated by limiting laser pulse widths to 670 ns and operating the system under closed-cycle refrigeration at a temperature of 10 K.

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“…Focal plane array detector with microbolometer structure has been successfully used in the middle-infrared (3-5 μm) and far-infrared (8-14 μm) wave band imaging [12][13][14]. But the detector indicates very weak responsivity to THz radiation because that membrane material and micro-bridge structure shows very low THz wave absorption ratio [15]. So some improvement of the micro-bridge should be done to increase the responsivity about THz radiation.…”

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confidence: 99%

Fabrication and parameters calculation of room temperature terahertz detector with micro-bridge structure

Wang

Gou

et al. 2014

J Infrared Milli Terahz Waves

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Room temperature terahertz (THz) detector indicates great potentials in imaging application because of real-time, compact bulk and unique spectral characteristics. Different dimension THz detectors based on micro-bridge structure were designed and simulated to get optimizing microbolometer parameters from the simulation results of membrane temperature changing and THz absorption. Those microbolometers were fabricated with complex semiconductor process and three dimension deformations of micro-bridges were obtained by laser scanning confocal microscope to identify the focal plane array micro-bridge design. The noise equivalent power of THz detector achieves 123 pW/Hz 1/2 and average response time of the detector is 6.7 ms, which is suitable for the application of active THz imaging.

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Detection of 3.4 THz radiation from a quantum cascade laser using a microbolometer infrared camera

Cited by 15 publications

References 12 publications

Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

Al/SiOx/Al single and multiband metamaterial absorbers for terahertz sensor applications

Optimization of a 3.6-THz quantum cascade laser for real-time imaging with a microbolometer focal plane array

Fabrication and parameters calculation of room temperature terahertz detector with micro-bridge structure

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