Archimedes spiral beam: composite of a helical-axicon generated Bessel beam and a Gaussian beam.

This paper introduces a structured beam with Archimedes spiral intensity distribution. The Archimedes spiral (AS) beam is the composite of a helical-axicon generated (HAG) Bessel beam and a Gaussian (GS) beam. We observed the spiral intensity patterns using computational holography, achieving the tuning over spiral arms number and spiral spacing. Analyzing the propagation dynamics of AS beams, we present that the spiral intensity will reverse beyond the maximum diffraction-free distance. Before and after the beam reverse, the spiral spacing remains constant, but the spiral direction is opposite. In addition, we obtain the Archimedes spiral equations to describe the spiral intensity patterns. Unlike the beams with Fermat and hyperbolic spiral patterns, the intensity distributions of AS beams are isometrically spiral. The isometric spiral intensity makes it possible to form particle isometric channels. AS beams have potential application prospects in particle manipulation, microscopic imaging, and laser processing.

Comparison of focusing property and radiation force between autofocusing Bessel beams and focused Gaussian beams.

As abruptly autofocusing beams, autofocusing Bessel beams (ABBs) have been proven to be a class solution for the Helmholtz equation [Opt. Express31, 33228 (2023)10.1364/OE.500383]. In this paper, we use the Fresnel number as the basic parameter and accurately compare the focusing property and radiation force of ABBs versus focused Gaussian beams (FGBs) under the same Fresnel number. Unlike FGBs, ABBs can achieve autofocusing without the need for an initial focusing phase. Our analysis of the beam width defined by power in the bucket, revealed that FGBs exhibit uniform focusing along the straight line, whereas ABBs demonstrate accelerated focusing along the elliptic curve. At the same Fresnel number, FGBs exhibit a higher peak intensity in the focal plane, yet ABBs excel in gradient force on particles. In comparison to FGBs, ABBs exhibit smaller potential well widths, allowing for stable and precise trapping of high refractive index particles at the focal point. While FGBs are considered suitable for laser processing and ablation due to their high peak power density, ABBs possess significant advantages in optical manipulation due to their great gradient force. Furthermore, we conduct a comparative analysis between ABBs and circular Airy beams (CABs). The peak intensity and gradient force exhibited by CABs are slightly lesser than those of ABBs. CABs are appropriate for multi-point trapping along the axis, whereas ABBs are more suited for precise single-point trapping.

Focusing property of autofocusing Bessel beams.

We introduce what we believe to be a new family of abruptly autofocusing waves named autofocusing Bessel beams (ABBs). Since the beams only strongly influence the area near the focus, it holds promise for medical laser treatment and optical tweezers. By the angular spectrum method, ABBs are proved to be a class solution for the Helmholtz equation. The focal length is well-defined and easily tuned in our mathematical description. Under the finite energy limitation, the abruptly autofocusing and vortex characteristics of Gaussian-modulated ABBs are studied. Interestingly, we found a kind of abruptly autofocusing waves focusing twice on the propagation axis, which is formed by an ABB passing through a focusing lens. Dual-focus ABBs make it possible for a single laser to manipulate two particles on the propagation axis simultaneously. In the experiment, the autofocusing of ABBs and the dual focus of ABBs passing through a focusing lens are observed. This article provides a theoretical model and experimental protocol for studying abruptly autofocusing waves.

Development of a 2 µm Solid-State Laser for Lidar in the Past Decade.

The 2 µm wavelength belongs to the eye-safe band and has a wide range of applications in the fields of lidar, biomedicine, and materials processing. With the rapid development of military, wind power, sensing, and other industries, new requirements for 2 µm solid-state laser light sources have emerged, especially in the field of lidar. This paper focuses on the research progress of 2 µm solid-state lasers for lidar over the past decade. The technology and performance of 2 µm pulsed single longitudinal mode solid-state lasers, 2 µm seed solid-state lasers, and 2 µm high power solid-state lasers are, respectively, summarized and analyzed. This paper also introduces the properties of gain media commonly used in the 2 µm band, the construction method of new bonded crystals, and the fabrication method of saturable absorbers. Finally, the future prospects of 2 µm solid-state lasers for lidar are presented.

hsa-miR-607, lncRNA TUG1 and hsa_circ_0071106 can be combined as biomarkers in type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is a multifactorial disorder that leads to alterations in gene regulation. ncRNAs have the characteristics of tissue specificity, disease specificity, timing specificity, high stability and post transcriptional regulation effect. These preconditions are more conducive to promote ncRNA to become a new biomarker for clinical diagnosis. Our study aims to explore the relationship between circRNA, lncRNA, miRNA and T2DM, and to evaluate their diagnostic value for T2DM. A total of 101 pairs of T2DM and controls were conducted in the study. QRT-PCR was used to study the differential expression of circRNAs, miRNAs and lncRNAs. ROC curve was used to estimate their diagnostic value in T2DM. Compared with healthy controls, the expression levels of hsa_circ_0071106, hsa_circ_0000284, hsa_circ_0071271, hsa-miR-29a-5p, hsa-miR-3690, hsa-miR-607, lncRNA MEG3 and lncRNA TUG1were higher in T2DM (all P < 0.05). The AUCs of hsa_circ_0071106, hsa-miR-607 and lncRNA TUG1 for diagnosis of T2DM were 0.563,0.645 and 0.642, respectively. The combined AUC of hsa-miR-607, lncRNA TUG1 and hsa_circ_0071106 was 0.798 ([0.720~0.875], P < 0.001). Moreover, the sensitivity of combined diagnosis was 75.2% and the specificity was 100.0%. The levels of lncRNA TUG1, hsa-miR-607 and hsa_circ_0071106 in peripheral blood have potential clinical diagnostic value for T2DM.