Terahertz sideband-tuned quantum cascade laser radiation

Danylov, Andriy A.; Waldman, J.; Goyette, Thomas M.; Gatesman, Andrew J.; Giles, Robert H.; Li, Jin; Goodhue, W. D.; Linden, Kurt J.; Nixon, William E.

doi:10.1364/oe.16.005171

Cited by 13 publications

(4 citation statements)

References 18 publications

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“…Other approaches are based on coupling a QCL to a THz mixer in a heterodyne configuration with a hot electron bolometer (HEB) [28] or a Schottky diode [29]. …”

Section: Introductionmentioning

confidence: 99%

THz QCL-Based Cryogen-Free Spectrometer for in Situ Trace Gas Sensing

Consolino

Bartalini

Beere

et al. 2013

Sensors

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We report on a set of high-sensitivity terahertz spectroscopy experiments making use of QCLs to detect rotational molecular transitions in the far-infrared. We demonstrate that using a compact and transportable cryogen-free setup, based on a quantum cascade laser in a closed-cycle Stirling cryostat, and pyroelectric detectors, a considerable improvement in sensitivity can be obtained by implementing a wavelength modulation spectroscopy technique. Indeed, we show that the sensitivity of methanol vapour detection can be improved by a factor ≈ 4 with respect to standard direct absorption approaches, offering perspectives for high sensitivity detection of a number of chemical compounds across the far-infrared spectral range.

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“…Other approaches are based on coupling a QCL to a THz mixer in a heterodyne configuration with a hot electron bolometer (HEB) [28] or a Schottky diode [29]. …”

Section: Introductionmentioning

confidence: 99%

THz QCL-Based Cryogen-Free Spectrometer for in Situ Trace Gas Sensing

Consolino

Bartalini

Beere

et al. 2013

Sensors

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“…Substantial further improvement in S/N is anticipated with a balanced mixer designed to match the QCL frequency, approximately 5 dB from better coupling and 10 dB from AM noise reduction. The success with the mixer/QCL combination suggests other applications including compact local oscillators and tunable THz radiation by sideband generation at considerably higher power levels than previously obtained with a corner-cube mixer [19].…”

Section: Resultsmentioning

confidence: 86%

232 THz quantum cascade laser frequency-locked to the harmonic of a microwave synthesizer source

Danylov¹,

Light²,

Waldman³

et al. 2012

Opt. Express

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Frequency stabilization of a THz quantum cascade laser (QCL) to the harmonic of a microwave source has been accomplished using a Schottky diode waveguide mixer designed for harmonic mixing. The 2.32 THz, 1.0 milliwatt CW QCL is coupled into the signal port of the mixer and a 110 GHz signal, derived from a harmonic of a microwave synthesizer, is coupled into the IF port. The difference frequency between the 21st harmonic of 110 GHz and the QCL is used in a discriminator to adjust the QCL bias current to stabilize the frequency. The short-term frequency jitter is reduced from 550 kHz to 4.5 kHz (FWHM) and the long-term frequency drift is eliminated. This performance is compared to that of several other THz QCL frequency stabilization techniques.

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“…This is important in spectroscopy, communications and ranging applications, where predictable modulation sidebands need to be imparted next to the main laser line. This modulation scheme has been recently used for spectroscopy by mixing a 2.4 THz QCL with a 2-20 GHz microwave source in a Schottky diode [25]. The linearity of these metamaterial modulators combined with their compact size, allows them to be directly incorporated into a QCL package or used externally to modulate the intensity without any undesired effects on the QCL's performance.…”

Section: Discussionmentioning

confidence: 99%