We explore optical-to-terahertz conversion efficiencies which can be achieved with femto- and picosecond optical pulses in electro-optic crystals with periodically inverted sign of second-order susceptibility. Optimal crystal lengths, pulse durations, pulse formats and focusing are regarded. We show that for sufficiently short (femtosecond) optical pulses, with a pulsewidth much shorter than the inverse terahertz frequency, conversion efficiency does not depend on pulse duration. We also show that by mixing two picosecond pulses (bandwidth-limited or chirped), one can achieve conversion efficiency, which is the same as in the case of femtosecond pulse with the same pulse energy. Additionally, when the group velocity dispersion of optical pulses is small, one can substantially exceed Manley -Rowe conversion limit due to cascaded processes.
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http://dx.doi.org/10.1364/oe.14.002263 | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Chemistry, College of Science, King Khalid University, Abha 61413, P.O. Box 9004, Saudi Arabia.
Lead-free inorganic halide perovskites, specifically BaPX (X = Cl, F, I, Br) have gained attention in green photovoltaics due to their remarkable mechanical, optical, structural, and electronic properties. Using first-principles calculations, we investigated the mechanical, electronic, and optical characteristics of BaPX, revealing direct band gaps at the -symmetry point, assessed with the PBE and HSE functionals. The charge distribution analysis shows strong ionic bonding between Ba and halides and covalent bonding between P and halides.
View Article and Find Full Text PDFNanoscale
January 2025
State Key Laboratory of Biobased Fiber Manufacturing Technology, Tianjin Key Laboratory of Pulp and Paper, China Light Industry Key Laboratory of Papermaking and Biorefinery, Tianjin University of Science and Technology, No. 29, 13th Street, TEDA, Tianjin 300457, P. R. China.
The remarkable catalytic activity, optical properties, and electrochemical behavior of nanomaterials based on noble metals (NM) are profoundly influenced by their physical characteristics, including particle size, morphology, and crystal structure. Effective regulation of these parameters necessitates a refined methodology. Lignin, a natural aromatic compound abundant in hydroxyl, carbonyl, carboxyl, and sulfonic acid groups, has emerged as an eco-friendly surfactant, reducing agent, and dispersant, offering the potential to precisely control the particle size and morphology of NM-based nanomaterials.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry & Chemical Engineering, Tianjin University of Technology, Tianjin 300384, P. R. China.
As one of the main fragments in medical drugs, spirooxindole has received considerable attention from organic and medicinal chemists. In the past few decades, chemists have been searching for more straightforward and efficient methods to produce compounds containing a spirooxindole fragment. In this regard, isatin-derived Morita-Baylis-Hillman (MBH) carbonates have been widely used as versatile building blocks for the synthesis of spirooxindole structures.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, P. R. China.
High transductive loss at tissue injury sites impedes repair. The high dissipation characteristics in the electromechanical conversion of piezoelectric biomaterials pose a challenge. Therefore, supramolecular engineering and microfluidic technology is utilized to introduce slide-ring polyrotaxane and conductive polypyrrole to construct stress-electric coupling hydrogel microspheres.
View Article and Find Full Text PDFSmall
January 2025
The Department of Medical Imaging, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Xingangzhong Road 466, Guangzhou, 518037, P. R. China.
The self-assembly of hydrophobic organic phototherapeutic agents (OPTAs) with expansive planar structures into nanoparticles (NPs) represents a pivotal strategy to bolster their biocompatibility. However, the tight molecular packing within these NPs significantly influences the generation of reactive oxygen species (ROS) and the photothermal conversion efficiency (PCE), posing a substantial hurdle to elevating the efficacy of photodynamic therapy (PDT) and photothermal therapy (PTT) for such NPs. In this article, three OPTAs by donor engineering are synthesized.
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