Advanced Photonics Research最新文献

Microfluidic lab-on-a-chip (LOC) devices have become essential tools for multitudes of applications in various research fields. 3D printing of microfluidic LOC devices offers many advantages over more traditional manufacturing processes, including rapid prototyping and single-step fabrication of complex 3D structures. In this work, 3D-printed microfluidic devices are designed and fabricated for optical chromatography and sorting. Optical chromatography is performed by inserting a single-mode optical fiber into the device creating a counter-propagating laser beam to the fluid flow. Particles are separated depending on refractive index and size. To demonstrate optical sorting, a cross-type sorter 3D-printed microfluidic device is fabricated that directs the laser beam perpendicular to the flow direction. Design features such as a sloping channel and a channel configuration for 3D hydrodynamic focusing (to aid in controlled sample flow and particle position) help to optimize sorting performance. Stable optofluidic trapping and sorting are successfully achieved using the fabricated microfluidic devices. These results highlight the tremendous potential of 3D printing of microfluidic LOC devices for applications aimed at the optofluidic manipulation of micron-sized particles.

Global concern about microplastic (MP) and nanoplastic (NP) particles is continuously rising with their proliferation worldwide. Effective identification methods for MP and NP pollution monitoring are highly needed, but due to different requirements and technical challenges, much of the work is still in progress. Herein, the advanced optical imaging systems that are successfully applied or have the potential for MP identification are focused on. Compared with chemical and thermal analyses, optical methods have the unique advantages of being nondestructive and noncontact and allow fast detection without complex sample preprocessing. Furthermore, they are capable of revealing the morphology, anisotropy, and material characteristics of MP for their quick and robust detection. This review aims to present a comprehensive discussion of the relevant optical imaging systems, emphasizing their operating principles, strengths, and drawbacks. Multiple comparisons and analyses among these technologies are conducted in order to provide practical guidelines for researchers. In addition, the combination of optical and other alternative technologies is described and the representative portable MP detection devices are highlighted. Together, they shed light on the prospects for long-term MP pollution monitoring and environmental protection.

Chiral emission exhibiting a large degree of circular polarization (DCP) is important in diverse applications ranging from displays and optical storage to optical communication, bioimaging, and medical diagnostics. Although chiral luminescent materials can generate chiral emissions directly, they frequently suffer from either low DCP or low quantum efficiencies. Achieving high DCP and quantum efficiencies simultaneously remains extremely challenging. This review introduces an alternative approach to chiral emission. Chiral emission with large DCP can be readily achieved by combining conventional achiral emitters with chiral metasurfaces. Particularly, this article focuses on recent experimental and theoretical studies on perovskite metasurfaces and metacavities that employ achiral perovskite materials. First, chiral photoluminescence from extrinsic and intrinsic perovskite metasurfaces is explained together with theoretical discussions on metasurface design based on reciprocity and critical coupling. Chiral photoluminescence from other achiral materials is also explained. Subsequently, chiral electroluminescence from perovskite metacavities and other achiral materials is discussed. Finally, it is concluded with future perspectives. This review provides physical insights into how ideal chiral emission can be realized by optimizing the design of metasurfaces and metacavities. Compact chiral light sources with both near-unity DCP and strong emission intensities can have far-reaching consequences in a wide range of future applications.

Combining cellulose-based components with functional materials is highly interesting in various research fields due to the improved strength and stiffness of the materials combined with their low weight. Herein, the mechanical properties of opal films are improved by incorporating cellulose fibers and microcrystalline cellulose. This is evidenced by the increase in tensile strength of 162.8% after adding 10 wt% of microcrystalline cellulose. For this purpose, core–shell particles with a rigid, crosslinked polystyrene core and a soft shell of poly(ethyl acrylate) and poly(ethyl acrylate-co-hydroxyethyl methacrylate) are synthesized via starved-feed emulsion polymerization. The synthesized particles’ well-defined shape, morphology, and thermal properties are analyzed using transmission electron microscopy, scanning electron microscopy, and differential scanning calorimetry measurements. Free-standing mechanochromic opal films with incorporated cellulose and structural colors are obtained after processing the core–shell particles with cellulose via extrusion and the melt-shear organization technique. The homogeneous distribution of the cellulose within the composite material is investigated using fluorescent-labeled cellulose. The opal film's angle-dependent structural color is demonstrated using reflection spectroscopy.

Quantization effects in nanolaminate structures of oxide materials are proposed and experimentally demonstrated only recently. Herein, the material combination of amorphous silicon and SiO₂ deposited by magnetron sputtering is investigated and it is shown that the quantization effect can be observed indeed. Transmission electron microscopy characterization gives evidence of continuous layers of amorphous silicon and SiO₂ with well-defined interfaces. The deposition process is described and the tunability of the refractive index and the bandgap energy is demonstrated. By doing so, the advantages of this novel material over classical optical materials are shown and feasibility is proved. As an example, a longpass optical interference filter with edge at 720 nm is deposited using quantized nanolaminates as the high and SiO₂ as the low refractive index material. This filter can be deposited successfully with close match to the design. It shows a blocking range throughout the visible spectrum whereas a comparable filter based on SiO₂–TiO₂ only blocks 500–700 nm.

This review explores how artificial intelligence (AI) is transforming fluorescence microscopy, providing an overview of its fundamental principles and recent advancements. The roles of AI in improving image quality and introducing new imaging modalities are discussed, offering a comprehensive perspective on these changes. Additionally, a unified framework is introduced for comprehending AI-driven microscopy methodologies and categorizing them into linear inverse problem-solving, denoising, and nonlinear prediction. Furthermore, the potential of self-supervised learning techniques that address the challenges associated with training the networks are explored, utilizing unlabeled microscopy data to enhance data quality and expand imaging capabilities. It is worth noting that while the specific examples and advancements discussed in this review focus on fluorescence microscopy, the general approaches and theories are directly applicable to other optical microscopy methods.

Accurate and precise measurement of radiation energy delivered to and absorbed by the patient's tissue is of great importance in radiation therapy (RT) quality assurance. Radioluminescence (RL) dosimetry has shown great potential for high spatiotemporal resolution dose measurement of RT fields. Implementation of efficient RL dosimetry in RT requires multidisciplinary effort and skills in optics, medical physics, radiation physics, electronics, and imaging science. In this review, a wide overview of fundamentals and applications of RL properties of media for RT dosimetry with emphasis on their potential use for multidimensional, small-field, and ultra-high dose rate RT dosimetry is provided.

Luminescence lifetime is a crucial parameter in photophysical studies that bears essential physical and chemical information and that is used to quantify a variety of phenomena, from the determination of quenching mechanisms to temperature sensing and bioimaging. The current perception of lifetime measurement is that it is a trivial and fast experiment. However, despite this apparent simplicity, measuring luminescence decay and fitting the obtained data to a suitable model can be far more intricate. In this perspective, the influence of experimental parameters and fitting procedures on the determination of lifetimes are investigated and, through carefully chosen examples, it is shown that large variations, up to 10%, can be induced by varying parameters such as the data acquisition time, the baseline evaluation, or the mathematical fitting model. In order to present to a wider audience, detailed mathematical descriptions are kept out of the manuscript.

The charge carrier mobility in tris(4-carbazoyl-9-ylphenyl)amine (TCTA), a host and hole transport material typically used in organic light-emitting diodes (OLEDs), is measured using charge carrier electrical injection metal–insulator–semiconductor charge extraction by linearly increasing voltage (i-MIS-CELIV). By employing the injection current i-MIS-CELIV method, charge transport at time scales shorter than the transit times typically observed in standard MIS-CELIV is measured. The i-MIS-CELIV technique enables the experimental measurement of unequilibrated and pretrapped charge carriers. Through a comparison of injection and extraction current transients obtained from i-MIS-CELIV and MIS-CELIV, it is concluded that hole trapping is negligible in evaporated neat films of TCTA within the time-scales relevant to the operational conditions of optoelectronic devices, such as OLEDs. Furthermore, photocarrier generation in conjunction with i-MIS-CELIV (photo-i-MIS-CELIV) to quantify the properties of charge injection from the electrode to the semiconductor of the MIS devices is utilized. Based on the photo-i-MIS-CELIV measurements, it is observed that the contact resistance does not limit the injection current at the TCTA/molybdenum oxide/silver interface. Therefore, when TCTA is employed as the hole transport/electron-blocking layer in OLEDs, it does not significantly reduce the injection current and remains compatible with the high injection current densities required for efficient OLED operation.