139 citations · 822 across the 18 of their papers we have counts for
18 papers
Electrical tunability of terahertz nonlinearity in graphene
Sergey Kovalev, Hassan A. Hafez, Klaas-Jan Tielrooij +15
Graphene is conceivably the most nonlinear optoelectronic material. Its nonlinear optical coefficients in the terahertz (THz) frequency range surpass those of other materials by ma…
Tracing the dynamics of superconducting order via transient third harmonic generation
Min-Jae Kim, Sergey Kovalev, Mattia Udina +13
Ultrafast optical control of quantum systems is an emerging field of physics. In particular, the possibility of light-driven superconductivity with ultrashort laser pulses has attr…
Higher-harmonic generation in boron-doped silicon from band carriers and bound-dopant photoionization
Fanqi Meng, Frederik Walla, Sergey Kovalev +10
We investigate ultrafast harmonic generation (HG) in Si:B, driven by intense pump pulses with fields reaching ~100 kV/cm and a carrier frequency of 300 GHz, at 4 K and 300 K, both…
Dynamical interplay between superconductivity and charge-density-wave: a nonlinear terahertz study of coherently-driven 2H-NbSe2 and La2-xSrxCuO4
Liwen Feng, Jiayuan Cao, Tim Priessnitz +21
2H-NbSe2 is an archetypal system in which superconductivity and charge-density-wave (CDW) coexist and compete macroscopically with each other. In particular, this interplay also ma…
Milliwatt terahertz harmonic generation from topological insulator metamaterials
Klaas-Jan Tielrooij, Alessandro Principi, David Saleta Reig +16
Achieving efficient, high-power harmonic generation in the terahertz spectral domain has technological applications, for example in sixth generation (6G) communication networks. Ma…
Optical Rectification and Electro-Optic Sampling in Quartz
Vasileios Balos, Martin Wolf, Sergey Kovalev +1
We report electro-optic sampling (EOS) response and terahertz (THz) optical rectification (OR) in z-cut alpha-quartz. Due to its small effective second-order nonlinearity, echo-fre…
Ellipticity control of terahertz high-harmonic generation in a Dirac semimetal
Semyon Germanskiy, Renato M. A. Dantas, Sergey Kovalev +9
We report on terahertz high-harmonic generation in a Dirac semimetal as a function of the driving-pulse ellipticity and on a theoretical study of the field-driven intraband kinetic…
High-order nonlinear terahertz probing of the two-band superconductor MgB: Third- and fifth-order harmonic generation
C. Reinhoffer, P. Pilch, A. Reinold +16
We report on high-order harmonic generation in the two-band superconductor MgB driven by intense terahertz electromagnetic pulses. Third- and fifth-order harmonics are resolved…
Fano interference of the Higgs mode in cuprate high-Tc superconductors
Hao Chu, Sergey Kovalev, Zi Xiao Wang +31
Despite decades of search for the pairing boson in cuprate high-Tc superconductors, its identity still remains debated to date. For this reason, spectroscopic signatures of electro…
Band-selective third-harmonic generation in superconducting MgB: Possible evidence for Higgs amplitude mode in the dirty limit
Sergey Kovalev, Tao Dong, Li-Yu Shi +13
We report on time-resolved linear and nonlinear terahertz spectroscopy of the two-band superconductor MgB with the superconducting transition temperature K. Th…
Grating-graphene metamaterial as a platform for terahertz nonlinear photonics
Jan-Christoph Deinert, David Alcaraz Iranzo, Raul Perez +14
Nonlinear optics is an increasingly important field for scientific and technological applications, owing to its relevance and potential for optical and optoelectronic technologies.…
Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators at room temperature
S. Kovalev, K. -J. Tielrooij, J. -C. Deinert +13
Topologically-protected surface states present rich physics and promising spintronic, optoelectronic and photonic applications that require a proper understanding of their ultrafas…
Non-perturbative high-harmonic generation in the three-dimensional Dirac semimetal CdAs
Sergey Kovalev, Renato M. A. Dantas, Semyon Germanskiy +12
Harmonic generation is a general characteristic of driven nonlinear systems, and serves as an efficient tool for investigating the fundamental principles that govern the ultrafast…
Experimental evidence of inertial dynamics in ferromagnets
Kumar Neeraj, Nilesh Awari, Sergey Kovalev +17
The understanding of how spins move at pico- and femtosecond time scales is the goal of much of modern research in condensed matter physics, with implications for ultrafast and mor…
Phase-resolved Higgs response in superconducting cuprates
Hao Chu, Min-Jae Kim, Kota Katsumi +26
In high energy physics, the Higgs field couples to gauge bosons and fermions and gives mass to their elementary excitations. Experimentally, such couplings can be inferred from the…
Magnetic field dependence of antiferromagnetic resonance in NiO
Zhe Wang, S. Kovalev, N. Awari +7
We report on measurements of magnetic field and temperature dependence of antiferromagnetic resonances in the prototypical antiferromagnet NiO. The frequencies of the magnetic reso…
Superradiant Undulator Radiation for Selective THz Control Experiments at XFELs
Takanori Tanikawa, Suren Karabekyan, Sergey Kovalev +5
The generation of frequency-tunable, narrow-bandwidth and carrier-envelope-phase stable THz pulses with fields in the MV/cm regime that can be appropriately timed to the femtosecon…
THz Field Control of In-Plane Orbital Order in La0.5Sr1.5MnO4
Timothy A. Miller, Ravindra W. Chhajlany, Luca Tagliacozzo +6
In-plane anisotropic ground states are ubiquitous in correlated solids such as pnictides, cuprates and manganites. They can arise from doping Mott insulators and compete with phase…