In this study, we carried out 800-nm pump and ultra-broadband mid-infrared (MIR) probe spectroscopy with high time-resolution (70 fs) in bulk Ge. By fitting the time-resolved difference reflection spectra [ΔR(ω)/R(ω)] with the Drude model in the 200-5000 cm region, the time-dependent plasma frequency and scattering rate have been obtained. Through the calculation, we can further get the time-dependent photoexcited carrier concentration and carrier mobility. The Auger recombination essentially dominates the fast relaxation of photoexcited carriers within 100 ps followed by slow relaxation due to diffusion. Additionally, a novel oscillation feature is clearly found in time-resolved difference reflection spectra around 2000 cm especially for high pump fluence, which is the Lorentz oscillation lasting for about 20 ps due to the Coulomb force exerted just after the excitation.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5225453 | PMC |
| http://dx.doi.org/10.1038/srep40492 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
TiCT MXene Thin Films and Intercalated Species Characterized by IR-to-UV Broadband Ellipsometry.
J Phys Chem C Nanomater Interfaces
January 2025
Nanoscale Solid-Liquid Interfaces, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Schwarzschildstraße 8, 12489 Berlin, Germany.
MXenes are two-dimensional (2D) materials with versatile applications in optoelectronics, batteries, and catalysis. To unlock their full potential, it is crucial to characterize MXene interfaces and intercalated species in more detail than is currently possible with conventional optical spectroscopies. Here, we combine ultra-broadband ellipsometry and transmission spectroscopy from the mid-infrared (IR) to the deep-ultraviolet (UV) to probe quantitatively the composition, structure, transport, and optical properties of spray-coated TiCT MXene thin films with varying material properties.
View Article and Find Full Text PDFUltra-Broadband Perfect Absorbers Based on Biomimetic Metamaterials with Dual Coupling Gradient Resonators.
Adv Mater
December 2024
Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang, 110819, China.
Ultra-broadband metamaterial absorbers can achieve near-perfect absorption of omnidirectional electromagnetic waves, crucial for light utilization and manipulation. Traditional ultra-broadband metamaterials rely on the superposition of different resonator units either in the plane or in perpendicular directions to broaden absorption peaks. However, this approach is subject to quantity restrictions and complicates the fabrication process.
View Article and Find Full Text PDFTellurium/Bismuth Selenide van der Waals Heterojunction for Self-Driven, Broadband Photodetection and Polarization-Sensitive Application.
Small
December 2024
State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China.
Broadband detection technology is crucial in the fields of astronomy and environmental surveying. Two dimensional (2D) materials have emerged as promising candidates for next-generation broadband photodetectors with the characteristics of high integration, multi-dimensional sensing, and low power consumption. Among these, 2D tellurium (Te) is particularly noteworthy due to its excellent mobility, tunable bandgap, and air stability.
View Article and Find Full Text PDFHybrid plasmonic metamaterials: towards enhanced ultra broadband and wide-angle solar absorption for energy harvesting.
Phys Chem Chem Phys
January 2025
Department of Electrical Engineering, Faculty of Engineering, University of Zabol, 9861335856 Zabol, Iran.
In this paper, we have investigated a hybrid metamaterial seven-layer solar absorber. The absorber has remarkable characteristics, including ultra-broadband perfect absorption capability, near-perfect absorption at wide angles, and insensitivity to polarization. The structure exhibits an average absorption of 98.
View Article and Find Full Text PDFUltra-broadband and wide-angle nonreciprocal thermal emitter based on Weyl semimetal metamaterials.
Nanophotonics
March 2024
Taizhou Hospital, Zhejiang University, Taizhou, China.
Article Synopsis
- Nonreciprocal thermal radiation can differ in emissivity at specific angles, challenging traditional Kirchhoff's law, and creating opportunities for thermal emitters that don’t rely on magnetic fields.
- The proposed mid-infrared thermal emitter operates between 12 μm to 20 μm with a wide angular range of 16° to 88°, utilizing a multilayered structure of Weyl semimetals and dielectrics.
- This innovation optimizes emissivity across various angles and wavelengths, indicating potential applications in areas like radiative cooling, medical sensing, and energy conversion.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!