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Detachment limited interlayer transport processes during SrTiO3 pulsed laser epitaxy
Jeffrey G. Ulbrandt, Xiaozhi Zhang, Randall L. Headrick
https://arxiv.org/abs/2509.19181 htt…

Detachment limited interlayer transport processes during SrTiO3 pulsed laser epitaxy
Pulsed laser epitaxial growth is characterized by high instantaneous deposition rates that leads to the nucleation of transient islands, both on surface terraces, and on top of stable islands formed during previous deposition pulses. We report results from combined in-situ X-ray reflectivity and kinetic Monte Carlo (kMC) simulations. Specular reflectivity monitors interlayer transport, while diffuse scattering reveals the evolution of in-plane length scales, both during the recovery time betwee…

Impact of a Reflecting Material on a Search for Neutron--Antineutron Oscillations using Ultracold Neutrons
Hiroyuki Fujioka, Takashi Higuchi
https://arxiv.org/abs/2508.17725 htt…

Impact of a Reflecting Material on a Search for Neutron--Antineutron Oscillations using Ultracold Neutrons
We investigate neutron--antineutron oscillations of ultracold neutrons in a storage bottle represented by a one-dimensional potential. The experimental sensitivity is determined by the annihilation rate of antineutrons. Its dependence on the antineutron reflectivity and the relative phase shift between the neutron and the antineutron wavefunctions by a reflection from the wall is derived. Optimization of the antineutron pseudopotential was found crucial to maximize the sensitivity of the experi…

Atomically resolved electron reflectivity at a metal/semiconductor interface
Ding-Ming Huang, Jian-Huan Wang, Jie-Yin Zhang, Yuan Yao, H. Q. Xu, Jian-Jun Zhang
https://arxiv.org/abs/2510.07970

Atomically resolved electron reflectivity at a metal/semiconductor interface
An atomically flat interface is achieved between face-centered cubic Al and diamond lattice Ge via molecular beam epitaxy (MBE). Based on the measurements of scanning tunneling microscopy (STM), we demonstrate an atomically resolved lateral periodic change of the electron reflectivity at the Al/Ge interface. The variation of electron reflectivity is up to 24% in lateral 2 nm. We speculate that the change of reflectivity results from the local electronic states at the Al/Ge interface. This pheno…

Impulsive excitation of a solid by extreme contrast, high intensity femtosecond laser pulses
Sagar Dam, Jian Fuh Ong, Sk Rakeeb, Ameya Parab, Aparajit C, Anandam, Amit D Lad, Yash M Ved, M Krishnamurthy, Kazuo A Tanaka, G Ravindra Kumar
https://arxiv.org/abs/2508.13649

Impulsive excitation of a solid by extreme contrast, high intensity femtosecond laser pulses
We present the ultra-fast dynamics of the interaction between a high-intensity extreme contrast (expected to be around 1e-18 at hundreds of picoseconds timescale) femtosecond laser and a solid. Simultaneous measurements of probe Doppler spectrometry and reflectivity in pump-probe experiments reveal the presence of extreme pressure in the solid density region, which triggers a long-lived (about 15 ps) strong inward shock. Hydrodynamic simulations accurately replicate these observations, providin…

Critical photoinduced reflectivity relaxation dynamics in single-layer Bi-based cuprates near the pseudogap end point
T. Shimizu, R. Tobise, T. Kurosawa, S. Tsuchiya, M. Oda, Y. Toda, V. V. Kabanov, D. Mihailovic, T. Mertelj
https://arxiv.org/abs/2508.21298

Critical photoinduced reflectivity relaxation dynamics in single-layer Bi-based cuprates near the pseudogap end point
A comprehensive study of photoinduced transient reflectivity dynamics in heavily overdoped single-layer cuprate (Bi,Pb)$_{2}$Sr$_{2}$CuO$_{6+δ}$ (Pb-Bi2201), across the end points of the pseudogap and superconducting phases, has been conducted using optical ultrafast time-resolved pump-probe spectroscopy. In the Pb-Bi2201 just before reaching the pseudogap end point, the transient reflectivity dynamics above $T_{\rm c}$ resemble the pseudogap response observed in optimally doped La-Bi2201. At …

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Earth Is Getting Darker, Literally, and Scientists Are Trying To Find Out Why
For decades, scientists assumed that symmetry between the reflectivity of Earth’s hemispheres was a “fundamental property” of our planet. Now, that’s changed.

Ultrafast cooperative electronic, structural, and magnetic switching in an altermagnet
Tiangao Lu, Ao Wu, Junxiang Li, Meng Zeng, Di Cheng, Chang Liu, Jiangbin Gong, Xinwei Li
https://arxiv.org/abs/2509.11722

Ultrafast cooperative electronic, structural, and magnetic switching in an altermagnet
Femtosecond laser control of antiferromagnetic order is a cornerstone for future memory and logic devices operating at terahertz clock rates. The advent of altermagnets -- antiferromagnets with unconventional spin-group symmetries -- creates new opportunities in this evolving field. Here, we demonstrate ultrafast laser-induced switching in altermagnetic $α$-MnTe that orchestrates the concerted dynamics of charge, lattice, and spin degrees of freedom. Time-resolved reflectivity and birefringenc…

A Geometrically Consistent Matching Framework for Side-Scan Sonar Mapping
Can Lei, Hayat Rajani, Nuno Gracias, Rafael Garcia, Huigang Wang
https://arxiv.org/abs/2509.11255 https…

A Geometrically Consistent Matching Framework for Side-Scan Sonar Mapping
Robust matching of side scan sonar imagery remains a fundamental challenge in seafloor mapping due to view dependent backscatter, shadows, and geometric distortion. This paper proposes a novel matching framework that combines physical decoupling and geometric consistency to enhance correspondence accuracy and consistency across viewpoints. A self supervised multi branch network, derived from the Lambertian reflection model, decomposes raw sonar images into seabed reflectivity, terrain elevation…

Boreal Afforestation's Underestimated Cloud Influence on Earth's Energy Imbalance
Enoch Ofosu, Kevin Bradley Dsouza, Daniel Chukwuemeka Amaogu, J\'er\^ome Pigeon, Richard Boudreault, Juan Moreno-Cruz, Pooneh Maghoul, Yuri Leonenko
https://arxiv.org/abs/2508.09295

Boreal Afforestation's Underestimated Cloud Influence on Earth's Energy Imbalance
Earth's Energy Imbalance (EEI) is accelerating, partly due to declining planetary albedo from reduced cloud cover. Boreal afforestation can either mitigate or exacerbate this trend through competing biophysical feedbacks. While snow masking reduces surface albedo (+0.5 to +2.5 $W/m^2$ warming), forests can enhance low-level cloud cover (0.1-0.5%) and increase cloud reflectivity via biogenic volatile organic compounds (BVOCs), producing potential cooling (-1.8 to -6.7 $W/m^2$). This BVOC-aerosol…

Highly Efficient and Broadband Optical Delay Line towards a Quantum Memory
Yu Guo, Anindya Banerji, Jia Boon Chin, Arya Chowdhury, Alexander Ling
https://arxiv.org/abs/2509.02096

Highly Efficient and Broadband Optical Delay Line towards a Quantum Memory
We demonstrate a high-efficiency, free space optical delay line utilizing a nested multipass cell architecture. This design supports extended optical paths with low loss, aided by custom broadband dielectric coating that provides high reflectivity across a wide spectral bandwidth. The cell is characterized using polarization-entangled photon pairs, with signal photons routed through the delay line and idler photons used as timing reference. Quantum state tomography performed on the entangled pa…

High-reflectivity homoepitaxial distributed Bragg reflectors for photonic applications
Helena Janowska, Anna Musia{\l}, Grzegorz S\k{e}k
https://arxiv.org/abs/2507.20211 https:/…

High-reflectivity homoepitaxial distributed Bragg reflectors for photonic applications
Distributed Bragg reflectors (DBRs) are one of the basic photonic structures used to define microcavities for fundamental light-matter coupling studies, as well as to optimize performance of optoelectronic and photonic devices, e.g., lasers or non-classical light sources. The reflectivity of these structures depends critically on the refractive index contrast between the two quarter-wavelength thick layers constituting the DBR. At the same time, epitaxial fabrication process limits the choice o…

Plasmon-enhanced ultrafast time-resolved spectroscopy of NV-containing diamond
Yuta Kimura, Toshu An, Muneaki Hase
https://arxiv.org/abs/2508.18762 https://

Plasmon-enhanced ultrafast time-resolved spectroscopy of NV-containing diamond
We investigated ultrafast nonlinear optical effects in nitrogen-vacancy (NV)-containing diamond which is in contact with a gold-coated blazed diffraction grating using a pump-probe reflectivity technique. The reflectivity change caused by optical Kerr effect and two-photon absorption was enhanced several times because of the electric field enhancement induced by the propagating surface plasmon (PSP). Furthermore, by performing measurements with varying the incident angle of the pump beam and nu…

High-pressure electronic states in semiconductors studied by infrared spectroscopy: metallization and band gap tuning in Mg$_2$Si, InAs and InSb
Hidekazu Okamura, Haruna Okazaki, Katsunori Marugaku, Subin Lee, Tomoki Yoneda, Haruhiko Udono, Yoshihisa Mori, Mitsuhiko Maesato, Hiroshi Kitagawa, Yuka Ikemoto, Taro Moriwaki
https://arxiv.org/a…

High-pressure electronic states in semiconductors studied by infrared spectroscopy: metallization and band gap tuning in Mg$_2$Si, InAs and InSb
In this article, a brief introduction is first given on infrared studies of materials at high pressures using a diamond anvil cell. Then, our recent results of high-pressure infrared studies are described for Mg$_2$Si, InAs, and InSb. For Mg$_2$Si, pressure-induced metallization at pressures near 10 GPa were clearly demonstrated for both carrier-doped and undoped Mg$_2$Si by large increases of reflectivity. For InAs and InSb, their band gap ($E_g$) increased rapidly and almost linearly with pre…

Earth Is Getting Darker, Literally, and Scientists Are Trying To Find Out Why https://www.404media.co/earth-is-getting-darker-literally-and-scientists-are-trying-to-find-out-why/

Unraveling energy flow mechanisms in semiconductors by ultrafast spectroscopy: Germanium as a case study
Grazia Raciti, Bego\~na Abad, Riccardo Dettori, Raja Sen, Aswathi K. Sivan, Jose M. Sojo-Gordillo, Nathalie Vast, Riccardo Rurali, Claudio Melis, Jelena Sjakste, Ilaria Zardo
https://arxiv.org/abs/2508.10544

Unraveling energy flow mechanisms in semiconductors by ultrafast spectroscopy: Germanium as a case study
Semiconductor materials are the foundation of modern electronics, and their functionality is dictated by the interactions between fundamental excitations occurring on (sub-)picosecond timescales. Using time-resolved Raman spectroscopy and transient reflectivity measurements, we shed light on the ultrafast dynamics in germanium. We observe an increase in the optical phonon temperature in the first few picoseconds, driven by the energy transfer from photoexcited holes, and the subsequent decay in…

Hidden phonon-assisted charge density wave transition in BaFe2Al9 revealed by ultrafast optical spectroscopy
Lei Wang, Mingwei Ma, Jiangxu Li, Liucheng Chen, Bingru Lu, Xiang Li, Feng Jin, Elbert E. M. Chia, Jianlin Luo, Rongyan Chen, Peitao Liu, Fang Hong, Xinbo Wang
https://arxiv.org/abs/2510.05908…

Hidden phonon-assisted charge density wave transition in BaFe2Al9 revealed by ultrafast optical spectroscopy
The interplay between electronic and lattice degrees of freedom is fundamental to charge density wave (CDW) formation, yet the microscopic origin often remains elusive. Here, we investigate the transient optical response of the intermetallic compound BaFe2Al9 using polarization-resolved ultrafast optical spectroscopy. We identify a discontinuous sign reversal in the transient reflectivity at Tc ~ 110 K, providing unambiguous evidence for the first-order transition. The anisotropic quasiparticle…

A new diffuse reflector filament for additive manufacturing of 3D printing finely-segmented plastic scintillator
S. Berns, E. Boillat, S. Hugon, A. Boyarintsev, B. Grynyov, N. Karavaeva, A. Krech, S. Minenko, T. Sibilieva, M. Sibilyev, A. De Roeck, T. Dieminger, U. Kose, B. Li, A. Rubbia, D. Sgalaberna, T. Weber, J. W\"uthrich, X. Zhao
https://

A new diffuse reflector filament for additive manufacturing of 3D printing finely-segmented plastic scintillator
This study presents the development and characterization of a novel white reflective filament suitable for additive manufacturing of finely segmented plastic scintillators using 3D printing. The filament is based on polycarbonate (PC) and polymethyl methacrylate (PMMA) polymers loaded with titanium dioxide (TiO$_2$) and polytetrafluoroethylene (PTFE) to enhance reflectivity. A range of filament compositions and thicknesses was evaluated through optical reflection and transmittance measurements.…

Energy-density-driven ultrafast electronic excitations in a cuprate superconductor
Alessandra Milloch (Department of Mathematics and Physics, Universit\`a Cattolica del Sacro Cuore, Brescia, Italy, ILAMP), Francesco Proietto (Department of Mathematics and Physics, Universit\`a Cattolica del Sacro Cuore, Brescia, Italy, Department of Physics and Astronomy, KU Leuven, Leuven, Belgium), Naman Agarwal (Elettra - Sincrotrone Trieste S.C.p.A., Trieste, Italy), Laura Foglia (Elettra - Sincrot…

Energy-density-driven ultrafast electronic excitations in a cuprate superconductor
Controlling nonequilibrium dynamics in quantum materials requires ultrafast probes with spectral selectivity. We report femtosecond reflectivity measurements on the cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ using free-electron laser extreme-ultraviolet (23.5--177~eV) and near-infrared (1.5~eV) pump pulses. EUV pulses access deep electronic states, while NIR light excites valence-band transitions. Despite these distinct channels, both schemes produce nearly identical dynamics: above …

Adsorption-induced surface magnetism
Milo\v{s} Baljozovi\'c, Shiladitya Karmakar, Andr\'e L. Fernandes Cauduro, Mothuku Shyam Sundar, Marco Lozano, Manish Kumar, Diego Soler Polo, Andreas K. Schmid, Ashutosh V. Bedekar, Pavel Jelinek, Karl-Heinz Ernst
https://arxiv.org/abs/2510.03897

Adsorption-induced surface magnetism
We report the emergence of adsorption-induced magnetism from heterohelicene molecules on a non-magnetic Cu(100) surface. Spin-polarized low-energy electron microscopy (SP-LEEM) measurements reveal spin-dependent electron reflectivity for enantiopure 7,12,17-trioxa[11]helicene (TO[11]H) monolayers, indicating the formation of a spin-polarized state localized in the topmost copper layer. Control experiments on clean Cu(100) and TO[11]H on highly oriented pyrolytic graphite show no such effect, ex…

Ultrafast Dynamics of Spin-Orbit Entangled Excitons Coupled to Magnetic Ordering in van der Waals Antiferromagnet NiPS3
Sidhanta Sahu, Anupama Chauhan, Poulami Ghosh, Sayan Routh, Ruturaj Puranik, Setti Thirupathaiah, Siddhartha Lal, Shriganesh Prabhu S, Chiranjib Mitra, N. Kamaraju
https://arxiv.org/abs/2509.04900

Ultrafast Dynamics of Spin-Orbit Entangled Excitons Coupled to Magnetic Ordering in van der Waals Antiferromagnet NiPS3
Spin-orbit entangled excitons (SOEE) in two-dimensional (2D) antiferromagnets provide a direct access to explore unconventional many body interactions in correlated electron systems. In this work, we carry out a detailed investigation using non-degenerate isotropic and anisotropic pump-probe reflection spectroscopy to probe the ultrafast dynamics of SOEE and their coupling to spin fluctuations in NiPS3. Transient reflectivity data reveals acoustic phonon oscillations at ~ 27 GHz, along with two…

Dynamic compression of glassy GeO$2$ up to the TPa range and first observation of shock induced crystallization
R. Torchio, J. A. Hernandez, A. Cordone, S. Balugani, T. Vinci, A. Ravasio, C. Pepin, N. Sevelin-Radiguet, E. Guillam, F. Dorchies, A. Benuzzi
https://arxiv.org/abs/2508.20695

Dynamic compression of glassy GeO$2$ up to the TPa range and first observation of shock induced crystallization
In this work we present an extensive study of glassy GeO$_2$ under laser induced dynamic compression. New VISAR and SOP data provide the extension of Hugoniot EoS up to the TPa range for this material including temperature measurements. Reflectivity data at both 532 and 1064 nm wavelenght are also reported. In the low compression range we observe changes of the optical properties from transparent, to opaque, to metallic state. The second part of this work describes a further laser shock experim…