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Related papers: Direct observation of terahertz frequency comb gen…

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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

The effectiveness of self-mixing interferometry has been demonstrated across the electromagnetic spectrum, from visible to microwave frequencies, in a plethora of sensing applications, ranging from distance measurement to material analysis,…

We investigate terahertz emission from two-color fs-laser-induced microplasmas. Under strongest focusing conditions, microplasmas are shown to act as point-sources for broadband terahertz-to-far-infrared radiation, where the emission…

Laser frequency combs are coherent light sources that emit a broad spectrum consisting of discrete, evenly spaced narrow lines, each having an absolute frequency measurable within the accuracy of an atomic clock. Their development, a decade…

Optics · Physics 2017-06-13 Albert Schliesser , Nathalie Picqué , Theodor W. Hänsch

The possibility of generating spectral combs of petahertz bandwidth is demonstrated from amplified spontaneous emission (ASE) of a collisional plasma-based x-ray laser when its active medium is irradiated with a linearly polarized…

Optics · Physics 2025-05-20 I. R. Khairulin , V. A. Antonov , I. D. Morskov , M. Yu. Ryabikin

The exploration of Terahertz (THz) waves has captivated researchers across diverse scientific disciplines such as physics, spectroscopy, chemistry, biology, and engineering, driven by the myriad applications these waves offer. Within this…

Plasma Physics · Physics 2026-01-08 A. A. Molavi Choobini , S. S. Ghaffari-Oskooei , M. Shahmansouri , F. M. Aghamir

We report on the generation of mid-infrared Kerr frequency combs in high-finesse CaF$_2$ and MgF$_2$ whispering-gallery mode resonators pumped with continuous wave room temperature quantum cascade lasers. The combs were centered at…

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

The remarkable precision of frequency comb (FC) lasers is transferred to the extreme ultraviolet (XUV, wavelengths shorter than 100 nm), a frequency region previously not accessable to these devices. A frequency comb at XUV wavelengths near…

THz quantum cascade lasers based on a novel buried cavity geometry are demonstrated by combining double-metal waveguides with proton implantation. Devices are realised with emission at 2.8 THz, displaying ultra low threshold currents of 19…

Materials Science · Physics 2009-11-11 S. Dhillon , J. Alton , S. Barbieri , C. Sirtori , A. de Rossi , M. Calligaro , H. E. Beere , D. Ritchie

Strategies and concepts for the design of THz emitters based on the quantum cascade scheme are analyzed and modeled in terms of a fully three-dimensional Monte Carlo approach; this allows for a proper inclusion of both carrier-carrier and…

Materials Science · Physics 2009-11-07 R. Koehler , R. C. Iotti , A. Tredicucci , F. Rossi

We present a single-shot detection method of terahertz-correlated second harmonic generation in plasma-based sources by directly mixing an optical probe into femtosecond laser-induced plasma filaments in air. The single-shot second harmonic…

We describe a coherent mid-infrared continuum source with 700 cm-1 usable bandwidth, readily tuned within 600 - 2500 cm-1 (4 - 17 \mum) and thus covering much of the infrared "fingerprint" molecular vibration region. It is based on…

Quantum Physics · Physics 2015-06-04 Fritz Keilmann , Sergiu Amarie

Quantum cascade lasers (QCLs) facilitate compact optical frequency comb sources that operate in the mid-infrared and terahertz spectral regions, where many molecules have their fundamental absorption lines. Enhancing the optical bandwidth…

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…

A recent publication on arXiv:1905.00668 suggests that the phase relationship within a frequency comb can be reconstructed from a heterodyne measurement using a reference comb. In principle, following this approach, such retrieval of…

Optics · Physics 2019-05-14 Günter Steinmeyer

This study investigates the interaction between frequency combs and optical feedback effects in Quantum Cascade Lasers (QCLs). The theoretical analysis reveals new phenomena arising from the interplay between comb generation and feedback.…

Optics · Physics 2023-10-17 Carlo Silvestri , Xiaoqiong Qi , Thomas Taimre , Aleksandar D. Rakić

Using a canonical pump-probe experimental technique, we studied the terahertz (THz) waves generation and detection via optical rectification and mixing in Czochralski-grown periodically poled Mg:Y:LiNbO3 (PPLN) crystals. THz waves with…

Optics · Physics 2009-11-11 G. H. Ma , G. Kh. Kitaeva , I. I. Naumova , S. H. Tang

We experimentally investigate the limits to 800 nm-to-terahertz (THz) energy conversion in lithium niobate at room temperature driven by amplified Ti:Sapphire laser pulses with tilted-pulse-front. The influence of the pump central…

We present on THz generation in the two-color gas plasma scheme driven by a high-power, ultrafast fiber laser system. The applied scheme is a promising approach for scaling the THz average power but it has been limited so far by the driving…