Physikalisches Institut, J. W. Goethe-Universit¨at, Max-von-Laue-Str 1, 60438 Frankfurt am Main, Germany.
Published: October 2010
AI Article Synopsis
Article Abstract
We demonstrate plasma-THz generation in ambient air with two-color (ω-2ω) optical excitation using input pulses with a bandwidth supporting sub-20-fs duration, yielding a continuous bandwidth exceeding 100 THz with no significant roll-off and a pulse energy of 360 nJ at a 1-kHz repetition rate. The key aspect in achieving this performance is an optimized geometry of the second-harmonic generation (SHG) crystal, producing a 2ω-field detuned from the second-harmonic of the ω-field, which promotes both a high polarization bandwidth and optimal ω-2ω temporal overlap in the plasma, as supported by theoretical results.
Department of Materials Science and Engineering and State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong, Hong Kong 999077, SAR, China.
* A new encapsulation strategy has led to the creation of CsPbX PNCs/PVP@PMMA composites that show improved luminescence, biocompatibility, and stability, with photoluminescence quantum yields reaching 70.24% for green and 98.26% for red emissions.
* These composites maintain high efficiency and low toxicity over long periods and can be used to develop white light-emitting diode (WLED) devices that emit warm white light, showcasing potential for solid-state lighting
Structural colors provide a highly stable and ecofriendly dyeing mechanism. The ability to adjust structural colors by a single pixel enhances their flexibility and application range. However, achieving single-pixel control and dynamic adjustment of structural colors remain a challenge yet.
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.
- Lithium niobate (LiNbO) is a promising material for nonlinear optics due to its strong nonlinear properties, but bulk crystals face challenges in achieving phase-matching for complex processes like high-harmonic generation (HHG).
- Researchers developed LiNbO metasurfaces that enhance light-matter interactions at the nanoscale, enabling efficient second-harmonic generation (SHG) and HHG, with demonstrated SHG efficiency of 5.1 × 10 cm GW and HHG reaching the 7th order with wavelengths as short as 226 nm.
- This advancement opens up possibilities for creating compact coherent white-light sources that can reach into the deep ultraviolet spectrum, which is valuable for various applications in
Broadband emission in the terahertz spectral region is a prerequisite for applications such as spectroscopy or white light sources. Appropriate signal powers and a compact design are advantageous for this use. A technology which meets these requirements are terahertz quantum cascade lasers.
Miscible-order fluoride-phosphate blocky phosphor (FBP), composed with ordered-phase of NaYFcrystals and unordered phase of tin-fluorophosphate glass, is prepared by a two-step process and luminescent properties of FBPs embedded with different particle sizes of NaYFcrystals are presented. High-frequency fluorescence from higher metastableD( = 1, 2 and 3) energy levels are effectively released in Eudoped fluoride crystals. Taking the blue emission of Snas the framework, multi-peak emissions from metastable energy levels are controlled to adjust the color coordinates of the FBP to the white-light region, which the color rendering index (CRI) reaches 89.
