Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line

Richter, Heiko; Pavlov, S.G.; Semenov, Alexey; Mahler, L.; Tredicucci, Alessandro; Beere, Harvey E.; Ritchie, D. A.; Hübers, Heinz‐Wilhelm

doi:10.1063/1.3324703

Cited by 68 publications

(37 citation statements)

References 21 publications

(15 reference statements)

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“…The QCL therefore requires additional frequency or phase stabilization in order to realize the full resolution of the receiver. A reliable approach to this is to use a molecular transitional line as an absolute reference frequency [10,11]. In this way a frequency discriminator can be produced using a simple gas cell containing any molecules that possess absorption lines in the spectral region of interest.…”

Section: Qcl Frequency Lockingmentioning

confidence: 99%

A 4.7THz heterodyne receiver for a balloon borne telescope

et al. 2014

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We report on the performance of a high sensitivity 4.7 THz heterodyne receiver based on a NbN hot electron bolometer mixer and a quantum cascade laser (QCL) as local oscillator. The receiver is developed to observe the astronomically important neutral atomic oxygen [OI] line at 4.7448 THz on a balloon based telescope. The single-line frequency control and improved beam pattern of QCL have taken advantage of a third-order distributed feedback structure. We measured a double sideband receiver noise temperature (T rec(DSB) ) of 815 K, which is ~ 7 times the quantum noise limit (hν/2k B ). An Allan time of 15 s at an effective noise fluctuation bandwidth of 18 MHz is demonstrated. Heterodyne performance was further supported by a measured methanol line spectrum around 4.7 THz.

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Section: Qcl Frequency Lockingmentioning

confidence: 99%

A 4.7THz heterodyne receiver for a balloon borne telescope

et al. 2014

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“…We will present the performance of the lasers in the cryocooler with respect to output power and beam profiles. Frequency stabilization to below 300 kHz full width at half maximum is achieved by locking to a molecular absorption line [3]. Spectroscopic experiments demonstrate the capability of this system for high resolution molecular spectroscopy.…”

Section: Resultsmentioning

confidence: 95%

THz quantum-cascade laser as a local oscillator for SOFIA

Richter

Pavlov

Semenov

et al. 2011

2011 International Conference on Infrared, Millimeter, and Terahertz Waves

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Abstract-We report on the development of a compact local oscillator (LO) for operation on board of SOFIA, namely for GREAT, the German Receiver for Astronomy at Terahertz Frequencies. The LO combines a quantum-cascade laser (QCL) with a compact, low-input-power Stirling cooler. The output power is sufficient for pumping a hot-electron bolometer mixer. Frequency stabilization is achieved by locking to a molecular absorption line. Detectors operating at room temperature can be used for the stabilization as well. High-resolution molecular spectroscopic experiments demonstrate the usability as LO for SOFIA.

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“…12,14 By feeding the output current of the HEB power detector to a lock-in amplifier, the derivative signal of the absorption profile is obtained. Then, a feedback signal from a PID controller is used to actively lock this derivative signal, maintained at zero value.…”

Section: -mentioning

confidence: 99%

Frequency and amplitude stabilized terahertz quantum cascade laser as local oscillator

Ren

Hayton

Hovenier

et al. 2012

Applied Physics Letters

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We demonstrate an experimental scheme to simultaneously stabilize the frequency and amplitude of a 3.5 THz third-order distributed feedback quantum cascade laser as a local oscillator. The frequency stabilization has been realized using a methanol absorption line, a power detector, and a proportional-integral-derivative (PID) loop. The amplitude stabilization of the incident power has been achieved using a swing-arm voice coil actuator as a fast optical attenuator, using the direct detection output of a superconducting mixer in combination with a 2nd PID loop. Improved Allan variance times of the entire receiver, as well as the heterodyne molecular spectra, are demonstrated. A terahertz (THz) quantum cascade laser (QCL) is the most promising solid-state source as the local oscillator (LO) for a high resolution heterodyne receiver operating at frequencies above 2 THz and, in particular, for a multi-pixel array receiver because of its high output power (typically mW). 1,2 Among different types of applications, a super-THz heterodyne receiver plays a vital role in astronomical observations, for instance to map a large number of fine structures and molecular lines associated with the formation of stars and planets in the Milky Way and nearby galaxies. 3 Those spectral lines at high frequencies are typically narrow ( a few MHz). Furthermore, the signals are, in general, very weak and deeply embedded within the noise. 3 The narrow spectral lines require either frequency or phase stabilization of a local oscillator. Since the intrinsic linewidth of a THz QCL is much narrower (

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Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line

Cited by 68 publications

References 21 publications

A 4.7THz heterodyne receiver for a balloon borne telescope

A 4.7THz heterodyne receiver for a balloon borne telescope

THz quantum-cascade laser as a local oscillator for SOFIA

Frequency and amplitude stabilized terahertz quantum cascade laser as local oscillator

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