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The Terahertz frequency range bears intriguing opportunities, beyond very advanced applications in spectroscopy and matter control. Peculiar quantum phenomena are predicted to lead to light emission by non-trivial mechanisms. Typically,…

The intense terahertz (THz) pulses facilitate the observation of various nonlinear optical effects and manipulation of material properties. In this work, we report a convenient approach that can produce strong broadband terahertz pulses…

Optics · Physics 2023-03-08 Yuxuan Wei , Jiaming Le , Chuanshan Tian

We report on an attempt to generate highly stable continuous terahertz (THz) wave by using optical frequency comb (OFC). About 10-nm wide OFC has been generated through a deep phase modulation of a 852 nm laser line in lithium niobate…

We present a \MF{terahertz} quantum cascade laser operating on a thermoelectric cooler up to a record-high temperature of 210.5 K. The active region design is based on only two quantum wells and achieves high temperature operation thanks to…

Quantum Cascade Lasers (QCLs) are generally designed to avoid negative differential conductivity (NDC) in the vicinity of the operation point in order to prevent instabilities. We demonstrate, that the threshold condition is possible under…

Mesoscale and Nanoscale Physics · Physics 2018-08-29 David O. Winge , Emmanuel Dupont , Andreas Wacker

Dual THz comb spectroscopy has the potential to be used as universal THz spectroscopy with high spectral resolution, high spectral accuracy, and broad spectral coverage; however, the requirement for dual stabilized femtosecond lasers…

Instrumentation and Detectors · Physics 2019-08-06 Guoqing Hu , Tatsuya Mizuguchi , Ryo Oe , Kazuki Nitta , Xin Zhao , Takeo Minamikawa , Ting Li , Zheng Zheng , Takeshi Yasui

We demonstrate a powerful tool for high-resolution mid-IR spectroscopy and frequency metrology with quantum cascade lasers (QCLs). We have implemented frequency stabilization of a QCL to an ultra-low expansion (ULE) reference cavity, via…

Detailed simulations for Terahertz quantum cascade lasers based on two-well designs are presented. We reproduce the maximal operation temperatures observed and attribute the degradation with temperature to the occupation of parasitic levels…

Optics · Physics 2022-10-24 Viktor Rindert , Ekin Önder. , Andreas Wacker

By introducing methyl fluoride (CH$_3$F) as a new gain medium for a quantum cascade laser-pumped molecular laser (QPML), we demonstrate continuous-wave lasing from more than 120 discrete transitions spanning the frequency range 0.25 to 1.3…

Increasing the average power of broadband, few-cycle terahertz (THz) sources is currently a topic of intense investigation, fueled by recent immense progress in high average power femtosecond laser driving sources at 1030 nm. However, many…

We derive a Markovian master equation for the single-electron density matrix, applicable to quantum cascade lasers (QCLs). The equation conserves the positivity of the density matrix, includes off-diagonal elements (coherences) as well as…

Mesoscale and Nanoscale Physics · Physics 2016-04-05 O. Jonasson , F. Karimi , I. Knezevic

Frequency-modulated (FM) combs are produced by mode-locked lasers in which the electric field has a linearly chirped frequency and nearly constant amplitude. This regime of operation occurs naturally in certain laser systems and constitutes…

Beginning with a continuous wave laser at 1064 nm, we generate a 30 GHz electro-optic frequency comb which contains 100 lines spanning 3 THz. The initial comb is subsequently amplified, spectrally broadened in normal dispersion photonic…

Dual-comb generation from a single laser cavity provides a simple and high-performance solution to time sampling applications. We demonstrate a compact single-cavity dual-comb laser operating at gigahertz repetition rates and high…

Room temperature operation of Terahertz Quantum Cascade Lasers (THz QCLs) has been a long-pursued goal to realize compact semiconductor THz sources. The progress toward high-temperature operation in THz QCLs has been relatively slow…

Applied Physics · Physics 2022-11-16 Ali Khalatpour , Man Chun Tam , Sadhvikas J. Addamane , John Reno , Zbig Wasilewski , Qing Hu

In a recent Letter [Appl. Phys. Lett. 82, 1015 (2003)], Williams et al. reported the development of a terahertz quantum cascade laser operating at 3.4 THz or 14.2 meV. We have calculated and analyzed the gain spectra of the quantum cascade…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 S. -C. Lee , A. Wacker

We investigate room temperature lasing of terahertz quantum cascade lasers using quantum dot chains as active material suitable for wireless communication and imaging technologies. Bandstructure calculations for such extended systems of…

Mesoscale and Nanoscale Physics · Physics 2021-03-10 Alexander Mittelstädt , Ludwig A. Th. Greif , Stefan T. Jagsch , Andrei Schliwa

We demonstrated combination of gapless terahertz (THz) comb with dual-comb spectroscopy, namely gapless dual-THz-comb spectroscopy, to achieve the spectral resolution equal to width of the THz comb tooth. The gapless THz comb was realized…

We present GaSb-based interband cascade lasers emitting at a center wavelength of 6.12 $\mu$m at 20$^\circ$C in continuous-wave operation up to a maximum operating temperature of 40$^\circ$C. Pulsed measurements based on broad area devices…

Quantum-dash (QD) mode-locked laser diodes (MLLD) lend themselves as chip-scale frequency comb generators for highly scalable wavelength-division multiplexing (WDM) links in future data-center, campus-area, or metropolitan networks. Driven…

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