Search

Improving the 3D resolution is a decisive step in the transition of direct laser writing from being limited to research use to being a powerful tool. Three‐color (3CL) lithography is expected to result in significantly higher resolution with two‐color lasers initiating polymerization in two steps and one‐color laser inhibiting polymerization. However, the 3CL process increases the complexity of the system and makes the influence of chromatic aberration worse which leads to non‐ideal writing results, which is ≈80 nm linewidth (≈λ/10) at present. In this study, the 3CL lithography is improved by introducing almost one color (1CL) instead of three colors to achieve subdiffraction 3D nanolithography based on two‐photon two‐step absorption and photoinhibition (T2A‐PI). Using benzil as a photoinitiator, a sub‐30 nm (<λ/17.5) lateral feature size, minimum 80 nm lateral, and 160 nm axial pitches are achieved, which, to our knowledge, is the best to be fabricated using the laser in the visible region. 3D woodpile photonic crystals and other high‐quality nanostructures are fabricated, demonstrating the unique advantages over existing direct laser writing technologies. [ABSTRACT FROM AUTHOR]

Two-photon lithography (TPL) plays a vital role in microstructure fabrication due to its high processing accuracy and maskless characteristics. To optimize the manufacturing quality deteriorated by the defocus of the substrate, an autofocus approach based on improved differential confocal microscopy (IDCM) is proposed in this paper. Through analyzing the intensity response signals from two detectors with symmetrical axial offset, the defocus amount is measured and compensated for with high precision and noise immunity to stabilize the substrate. The verification experiments on the coverslip reported a detection sensitivity of 5 nm, a repetitive measurement accuracy of less than 15 nm, and a focusing accuracy reaching around 5 nm. The consistency between simulation and characterization demonstrated the effectiveness and superior performance of the autofocus system for the high production quality of the metalens array. The proposed autofocus method shows promise for further application to the fabrication of complex structures on various substrates. [ABSTRACT FROM AUTHOR]

Advances in direct laser writing to attain super-resolution are required to improve fabrication performance and develop potential applications for nanophotonics. In this study, a novel technique using single-color peripheral photoinhibition lithography was developed to improve the resolution of direct laser writing while preventing the chromatic aberration characteristics of conventional multicolor photoinhibition lithography, thus offering a robust tool for fabricating 2D and 3D nanophotonic structures. A minimal feature size of 36 nm and a resolution of 140 nm were achieved with a writing speed that was at least 10 times faster than existing photoinhibition lithography. Super-resolution and fast scanning enable the fabrication of spin-decoupled metasurfaces in the visible range within a printing duration of a few minutes. Finally, a subwavelength photonic crystal with a near-ultraviolet structural color was fabricated to demonstrate the potential of 3D printing. This technique is a flexible and reliable tool for fabricating ultracompact optical devices. [ABSTRACT FROM AUTHOR]

Urinary luteinizing hormone (uLH) and urinary follicle-stimulating hormone (uFSH) have been shown to be useful screening and management tools for children with central precocious puberty. However, studies on uLH and uFSH reference intervals are scarce. Therefore, we aimed to establish reference intervals for uLH and uFSH, according to age, sex, and pubertal status in apparently healthy children aged 6–11 years. We performed detection capability, precision, accuracy by recovery, linearity, agreement analysis, and stability testing to analyze the method performance of uLH and uFSH. The Clinical Laboratory Standards Institute's C28-A3 criteria was used to establish the reference intervals. Both uLH and uFSH were stable at 4 °C for 52.6 h and 64.8 days, respectively. The total imprecision of uFSH is within the manufacturer's claim, while the total imprecision of uLH remained within tolerable bias. Both uLH and uFSH could be measured with acceptable detection capability. The recovery rates of the hormones were 87.6–98.8% and 102.8–103.4%, respectively, and therefore within acceptable limits. There were significant correlations between the serum and urine concentrations (LH: r=0.91, p<0.001; FSH: r=0.90, p<0.001). The reference intervals of uLH and uFSH were established according to age, sex, and pubertal status. We established reference intervals for uLH and uFSH based on age, sex and pubertal status to provide a non-invasive clinical screening tool for precocious puberty in children aged 6–11 years. [ABSTRACT FROM AUTHOR]

Photoinhibition lithography (PIL) is a nanoscale fabrication technique that uses multicolor visible light to enable the printing of arbitrary 3D structures beyond the diffraction limit. Photoinhibition allows the control and confinement of the exposed region for photoinitiation during the photolithographic process, thus improving the resolution of existing lithographic techniques, such as direct laser writing. Because PIL enables super‐resolution 3D printing, it has a multitude of applications. In this review, practical applications of PIL in the areas of photonics, data storage, and biotechnology are highlighted; in addition, its unique features are revealed. The theory and recent advances in PIL for sub‐diffraction printing and high‐throughput fabrication are also discussed. Besides, challenges and tentative solutions are discussed with the hope of providing a preliminary roadmap for technological breakthroughs in PIL to enable developments of resolution and throughput. [ABSTRACT FROM AUTHOR]

Pixel reassignment image scanning microscopy (PRISM) is a useful tool to improve the resolution of confocal laser scanning microscopy (CLSM) only equipped with a detector array. However, while it can improve the lateral resolution, it has little effect on the axial resolution. Here, new microscopy has been proposed which combines three-dimension fluorescence emission difference microscopy (3D FED) with PRISM to further improve three-dimension resolution. We call this method three-dimension pixel reassignment fluorescence emission difference microscopy (3D-PRFED). Detailed theoretical analysis and simulation are presented in this paper. Additionally, the performance of lateral and axial resolution improvement of this method has been demonstrated by imaging 100 nm fluorescent beads and nuclear pore complexes samples. Experiment results show that this method in our system can improve lateral resolution by a factor of 1.85 and axial resolution by a factor of 1.48 compared with CLSM. [ABSTRACT FROM AUTHOR]