arXiv subjects

Aday Cárdenas

Publications and source records attributed to Aday Cárdenas.

3 recordsLinked to original sources

arXiv2026

Programmable high-harmonic emission in solids through photon pathways

Ultrafast all-optical control of light emission is a central goal of extreme nonlinear optics, with implications for compact short-wavelength sources, petahertz optoelectronics, and label-free superresolution microscopy. High-harmonic generation in solids is a particularly attractive platform for this goal because it is highly sensitive to both the driving field and the material response, yet a generally applicable framework for controlling harmonic emission has remained elusive. Here, we demonstrate programmable control of high-harmonic emission in solids and show that it can be quantitatively described within a photon-pathway framework. We find that harmonic emission can be suppressed or enhanced by tuning two experimentally accessible quantities: the effective nonlinear order and the intrinsic emission phase. Across a wide range of semiconductors and dielectrics, this approach unifies parametric and non-parametric modulation, explains distinct delay-dependent spectral responses, and reproduces strong suppression, enhancement, and higher-order pathway revivals. Semiconductor Bloch equation simulations support the model and provide a complementary time-domain picture in which the control field reshapes the interference of sub-cycle emission events. These results establish high-harmonic generation in solids as a programmable emission process and provide a general route towards ultrafast optical switching, compact coherent short-wavelength sources, and label-free attosecond super-resolution microscopy.

physics.optics↗

arXiv2026

Contrasting ultrafast light-driven electron-hole interaction dynamics in monolayer MoS$_2$ and metallic NbSe$_2$

We study strong-field driven ultrafast dynamics and high-harmonic generation (HHG) in monolayer 2H-NbSe$_2$ and compare them with those of monolayer 2H-MoS$_2$ by solving the multiband reduced-density-matrix equations including time-dependent electron-electron interaction effects within the time-dependent Hartree + screened exchange (TD-HSEX). In MoS$_2$, these interactions strongly enhance the harmonic yield and modify the harmonic phases and angular emission patterns, wheras in NbSe$_2$ the yield enhancement is weaker but clear phase and angular changes remain. We trace these differences to the distinct optical resonances and to the different bands involved in the emission in each material. Finally, we show that carrier injection into empty bands of NbSe$_2$ differs qualitatively from interband excitation in MoS$_2$, and is well captured at a qualitative level by a Keldysh tunneling rate with a time-dependent band separation, allowing to control the timing and the region of injection of carriers to empty bands of the metal with the field parameters. Our work provides a framework to interpret ultrafast electron-hole interaction effects in experimental high harmonic generation spectra across semiconducting and metallic systems.

physics.optics↗

arXiv2025

Effects of Zero-Point Motion in the High Harmonic Generation Spectrum of Solids

The interpretation of high-harmonic generation (HHG) in solids typically relies on phenomenological dephasing times far shorter than what is expected from microscopic scattering processes. Here we show that zero-point fluctuations associated with optical phonons naturally suppress long-range electronic coherences and generate clean harmonic spectra without introducing ad-hoc decoherence parameters. Using a 1D semiconductor composed of two distinct sites per unit cell and realistic phonon amplitudes, we demonstrate that random per-site optical-phonon jitter reproduces the spectral sharpening typically attributed to ultrafast $T_2$ dephasing. In contrast, acoustic phonons and local strain, whose distortions are correlated over nanometer scales, produce negligible spectral cleaning. We further show that such long-range site coherence leads to carrier-envelope-phase-dependent effects in the HHG spectrum driven by long pulses, but these effects collapse once optical-phonon-induced decoherence is included. Our results (i) identify optical zero-point motion as a key mechanism governing coherence in solid-state HHG, (ii) demonstrate that it can be qualitatively modeled in periodic solids through site-distance-dependent dephasing, and (iii) suggest that CEP-resolved measurements can probe electronic coherence lengths and atomic fluctuations in crystalline materials.

physics.optics↗