ABSTRACT
Solid-state spin systems with nitrogen-vacancy (NV) centers in diamonds constitute an increasingly popular platform for quantum sensing. However, most existing platforms designed with ensemble NV centers exhibit a sensitivity that is significantly less than the theoretical maximum. This low sensitivity limits the expansion of the experimental results and application areas. In this study, the sensitivity is improved by increasing the pumping depth of the excitation beam to increase the number of particles involved in spin polarization at a given laser intensity. Compared with the proposed Airy beam with a long focal depth (25.46 λ) and the widely utilized Gauss beam pumping ensemble NV centers, the spin resonance factor fSR can be improved by 10.02%. This sensitivity-optimized approach enhances the functionality of sensors with NV centers.
ABSTRACT
Low-cost, small-sized, and easy integrated high-performance photodetectors for photonics are still the bottleneck of photonic integrated circuits applications and have attracted increasing attention. The tunable narrow bandgap of two-dimensional (2D) layered molybdenum ditelluride (MoTe2) from â¼0.83 to â¼1.1 eV makes it one of the ideal candidates for near-infrared (NIR) photodetectors. Herein, we demonstrate an excellent waveguide-integrated NIR photodetector by transferring mechanically exfoliated 2D MoTe2onto a silicon nitride (Si3N4) waveguide. The photoconductive photodetector exhibits excellent responsivity (R), detectivity (D*), and external quantum efficiency at 1550 nm and 50 mV, which are 41.9 A W-1, 16.2 × 1010Jones, and 3360%, respectively. These optoelectronic performances are 10.2 times higher than those of the free-space device, revealing that the photoresponse of photodetectors can be enhanced due to the presence of waveguide. Moreover, the photodetector also exhibits competitive performances over a broad wavelength range from 800 to 1000 nm with a highRof 15.4 A W-1and a largeD* of 59.6 × 109Jones. Overall, these results provide an alternative and prospective strategy for high-performance on-chip broadband NIR photodetectors.
ABSTRACT
Molybdenum sulfide (MoS2) as an emerging optoelectronic material, shows great potential for phototransistors owing to its atomic thickness, adjustable band gap, and low cost. However, the phototransistors based on MoS2have been shown to have some issues such as large gate leakage current, and interfacial scattering, resulting in suboptimal optoelectronic performance. Thus, Al-doped hafnium oxide (Hf1-xAlx) is proposed to be a dielectric layer of the MoS2-based phototransistor to solve this problem because of the relatively higher crystallization temperature and dielectric constant. Here, a high-performance MoS2phototransistor with Hf1-xAlxO gate dielectric layer grown by plasma-enhanced atomic layer deposition has been fabricated and studied. The results show that the phototransistor exhibits a high responsivity of 2.2 × 104A W-1, a large detectivity of 1.7 × 1017Jones, a great photo-to-dark current ratio of 2.2 × 106%, and a high external quantum efficiency of 4.4 × 106%. The energy band alignment and operating mechanism were further used to clarify the reason for the enhanced MoS2phototransistor. The suggested MoS2phototransistors could provide promising strategies in further optoelectronic applications.
ABSTRACT
Aluminum-doped Ga2O3(AGO) thin films were prepared by plasma-enhanced atomic layer deposition (PE-ALD). The growth mechanism, surface morphology, chemical composition, and optical properties of AGO films were systematically investigated. The bandgap of AGO films can be theoretically set between 4.65 and 6.8 eV. Based on typical AGO films, metal-semiconductor-metal photodetectors (PDs) were created, and their photoelectric response was examined. The preliminary results show that PE-ALD grown AGO films have high quality and tunable bandgap, and AGO PDs possess superior characterizations to undoped films. The AGO realized using PE-ALD is expected to be an important route for the development of a new generation of gallium oxide-based photodetectors into the deep-ultraviolet.
ABSTRACT
Social media have become crucial communication channels for human papilloma virus (HPV) patients to seek and receive social support that can benefit their physical and psychological health. To promote supportive communication on online social platforms, we analyzed 96,543 messages, including 7,407 posts and 89,136 comments, concerning social support on Baidu HPV Forum, one of China's largest online HPV support groups. We examined factors (i.e., threat and efficacy) in posts requesting social support associated with the amount of social support received in comments. Results revealed that the majority of social support messages received in comments represented informational support, whereas relatively few comments featured instrumental social support. Beyond that, high-threat, non-efficacy posts requesting social support received a greater amount of informational and emotional support in the comments than other types of posts requesting social support. Theoretical and practical implications of our study are discussed as well.
ABSTRACT
In this paper, the focusing characteristics of Bessel-Gaussian beams are studied by means of vector diffraction theory. The vector field distribution of the axisymmetric Bessel-Gaussian beam of a cylindrical vector is derived by calculating and adding Airy mixing modulation to the Bessel-Gaussian beam. It is found that with a series of regular focusing change characteristics, the focusing presents strong stability of the optical chain structure, and the number of optical chain links can be adjusted. At the same time, it is pointed out that in the case of a tightly focused helically polarized beam, the polarization in the focal region is not uniform, but there was a similar horizontal shift in focus. Finally, the relevant practical application scenarios are briefly introduced. The correlation focus shift conversion can be widely used in electronic acceleration, optical sampling and operation, and biological imaging.
ABSTRACT
Pathological myofibroblasts are often involved in skin scarring via generating contractile force and over-expressing collagen fibers, but no compound has been found to inhibit the myofibroblasts without showing severe toxicity to surrounding physiological cells. Here we report that di-rhamnolipid, a biosurfactant secreted by Pseudomonas aeruginosa, showed potent effects on scar therapy via a unique mechanism of targeted killing the myofibroblasts. In cell culture, the fibroblasts-derived myofibroblasts were more sensitive to di-rhamnolipid toxicity than fibroblasts at a concentration-dependent manner, and could be completely inhibited of their specific functions including α-SMA expression and collagen secretion/contraction. The anti-fibrotic function of di-rhamnolipid was further verified in rabbit ear hypertrophic scar models by presenting the significant reduction of scar elevation index, type I collagen fibers and α-SMA expression. In this regard, di-rhamnolipid treatment could be suggested as a therapy against skin scarring.
