Small optical volume terahertz emitting microdisk quantum cascade lasers

Dunbar, L. A.; Houdré, R.; Scalari, Giacomo; Sirigu, L.; Giovannini, Marcella; Faist, Jérôme

doi:10.1063/1.2719674

Cited by 63 publications

(31 citation statements)

References 9 publications

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“…Therefore, the frequency position of the peak gain becomes very sensitive to the electric field, which along with the waveguide loss frequency dependence sets the lasing frequency at 3.22 THz. At T max , the MC model predicts a peak-gain or equivalently a waveguide loss of 37.5 cm −1 , a value that is consistent with a previous measurement by cavity frequency pulling [35]. Since the employed MC model does not include stimulated emission, the simulated current and experimental laser IV should be compared only when transport is dominated by the non-radiative scattering, i.e.…”

Section: Analysis Of Lasing Frequencymentioning

confidence: 51%

Terahertz quantum cascade lasers operating up to ∼ 200 K with optimized oscillator strength and improved injection tunneling

Fathololoumi¹,

Dupont²,

Chan³

et al. 2012

Opt. Express

505

335

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630-631 (2008). 27. For the density matrix calculations, the electron temperature was chosen 90 K higher than lattice. Pure dephasing time constants of tunneling τ * = 0.35 ps, and of optical intersubband transition τ * ul = 1.1 ps were used. Intrawell intersubband scatterings by LO phonon, e-impurities and interface roughness were considered. The momentum dependance of scattering is averaged over the assumed Maxwell-Boltzmann distribution of carriers in the subbands. 28.

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Section: Analysis Of Lasing Frequencymentioning

confidence: 51%

Terahertz quantum cascade lasers operating up to ∼ 200 K with optimized oscillator strength and improved injection tunneling

Fathololoumi¹,

Dupont²,

Chan³

et al. 2012

Opt. Express

505

335

View full text Add to dashboard Cite

show abstract

“…2, the lasing frequency shifts monotonically and increases by 1.6 GHz from 30 to 46 mA (corresponding to 10.8 to 11.4 V), with the rate of 98 MHz/mA. This blue shift is most likely due to the frequency pulling of a Stark-shifted gain spectrum [20]. This observation indicates that the QCL behaves as a voltage controlled oscillator for the bias range of interest, which is required for phase-locking [7], [8].…”

Section: Measurement Results and Discussionmentioning

confidence: 99%

Phase-locking of a 2.7-THz quantum cascade laser to a mode-locked erbium-doped fibre laser

et al. 2010

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Abstract-We demonstrate phase-locking of a 2.7-THz metalmetal waveguide quantum cascade laser (QCL) to an external microwave signal. The reference is the 15th harmonic, generated by a semiconductor superlattice nonlinear device, of a signal at 182 GHz, which itself is generated by a multiplier-chain (x2x3x2) from a microwave synthesizer at 15 GHz. Both laser and reference radiations are coupled into a hot electron bolometer mixer, resulting in a beat signal, which is fed into a phase-lock loop. Spectral analysis of the beat signal (see fig. 1) confirms that the QCL is phase locked. This result opens the possibility to extend heterodyne interferometers into the far-infrared range.

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“…2, the lasing frequency shifts monotonically and increases by 1.6 GHz from 30 to 46 mA (corresponding to 10.8-11.4 V), with the rate of 98 MHz/mA. This blueshift is most likely due to the frequency pulling of a Stark-shifted gain spectrum [16]. The tuning mechanism, which has a time constant of approximately picoseconds, is much faster than the thermal tuning ͑Ͼ1 ms͒ that results in a redshift [7].…”

mentioning

confidence: 97%

Phase locking of a 27 THz quantum cascade laser to a microwave reference

et al. 2009

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We demonstrate the phase locking of a 2.7 THz metal-metal waveguide quantum cascade laser (QCL) to an external microwave signal. The reference is the 15th harmonic, generated by a semiconductor superlattice nonlinear device, of a signal at 182 GHz, which itself is generated by a multiplier chain ͑ϫ12͒ from a microwave synthesizer at ϳ15 GHz. Both laser and reference radiations are coupled into a bolometer mixer, resulting in a beat signal, which is fed into a phase-lock loop. The spectral analysis of the beat signal confirms that the QCL is phase locked. This result opens the possibility to extend heterodyne interferometers into the far-infrared range. To proceed with the applications of terahertz QCLs as LOs in a heterodyne spectrometer, the stabilization of the frequency or phase is required to either eliminate the frequency jitter or to reduce the phase noise. For a heterodyne interferometer either on the earth [4] or in space [5], the phase locking of multiple LOs to a common reference at low frequency is essential. Phase locking [6] a laser to a reference means to control the phase of the laser radiation field precisely. This serves not only to stabilize the frequency but also to transfer the line profile of the reference to the laser. In the case of frequency locking, the laser's average frequency is fixed, but its linewidth remains equal to the laser's intrinsic linewidth. Several experiments to stabilize a terahertz QCL have been published. They are the frequency locking of a 3.1 THz QCL to a far-infrared (FIR) gas laser [7], the phase locking of the beat signal of two lateral modes of a terahertz QCL to a microwave reference [8], and the phase locking of a 1.5 THz QCL to a multiplier chain LO source [9]. Since the multiplier chain source has been demonstrated only up to about 2 THz, for a practical solution for the use of a QCL as LO beyond this frequency, the phase needs to be locked to an external reference that can be generated conveniently and should preferably be far below the QCL frequency. Therefore, an important challenge is the demonstration of the phase locking of a singlemode terahertz QCL to a microwave reference signal (MRS), which is the scheme commonly used in existing solid-state LOs. The MRS should be multiplied to a terahertz frequency in the vicinity of the laser frequency to obtain a beat note or an intermediate frequency (IF). As demonstrated in the measurements of FIR gas laser frequency, the harmonics of MRS at 3.8 THz [10] and at 4.3 THz [11] can be generated by Josephson junction harmonic mixers, resulting in a beat between the laser and the upconverted frequencies. Another commonly used harmonic generator is a Schottky diode [12].In this Letter, we report the phase locking of a 2.7 THz QCL to a harmonic generated from an MRS by a semiconductor superlattice (SL) nonlinear device in combination with a multiplier chain. We demonstrate a practical phase-locking scheme that is extendable to a much higher frequency and quantify the phaselocked power.The QCL used is based on the doubl...

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Small optical volume terahertz emitting microdisk quantum cascade lasers

Cited by 63 publications

References 9 publications

Terahertz quantum cascade lasers operating up to ∼ 200 K with optimized oscillator strength and improved injection tunneling

Terahertz quantum cascade lasers operating up to ∼ 200 K with optimized oscillator strength and improved injection tunneling

Phase-locking of a 2.7-THz quantum cascade laser to a mode-locked erbium-doped fibre laser

Phase locking of a 27 THz quantum cascade laser to a microwave reference

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