分类: 光学 >> 量子光学 提交时间: 2023-02-19
摘要: Room-temperature continuous-wave operation of InGaAs/AlGaAs quantum well lasers directly grown on on-axis silicon (001) has been demonstrated. A 420 nm thick GaAs epilayer completely free of antiphase domains was initially grown on the silicon substrate in a metal-organic chemical vapor deposition system and the other epilayers including four sets of five-period strained-layer superlattices and the laser-structural layers were successively grown in a molecular beam epitaxy system. The lasers were prepared as broad-stripe Fabry-Perot ones with a stripe width of 21.5 um and a cavity length of 1 mm. Typically, the threshold current and the corresponding threshold current density are 186.4 mA and 867 A/cm2, respectively. The lasing wavelength is around 980 nm and the slope efficiency is 0.097 W/A with a single-facet output power of 22.5 mW at an injection current of 400 mA. This advancement makes the silicon-based monolithic optoelectronic integration relevant to quantum well lasers more promising with an enhanced feasibility.
分类: 护理学 >> 护理学 提交时间: 2023-04-22
摘要: Objective: To explore the effect of implementing manpower supermarket resourcebank management in the nursing human resource management of Jiangsu ProvinceAcademy of Traditional Chinese medicine. Methods: The concept of supermarket management was first developed and appliedto the administration of manpower services. Next, the structure of nursing nursinghuman resource management was established. By developing the commodity bankof the manpower supermarket, comprising ① general nurse bank, ②special post mobile bank ③ post ability refueling bank. The quality of goods is ensuredbycombining job training and recruitment unit criteria. In parallel, a standardizedselection path is created, including the standardization of the order-sending reviewprocess, the implementation of the commodity maintenance regulations, andthescreening of the conditions of the selection units, ensuring the streamlined operationof the manpower supermarket. Results: A total of 1,284 nurses were dynamically deployed in the hospital fromOctober 2021 to October 2022 in 31 different batches. In addition to boostingthequality of nursing human resource management and the quality of specialized nursingcare, the high frequency of staff deployment and orderly and innovative management decreased the rate of patient complaints and the turnover rate of nurses. Conclusion: It is worth learning from the manpower supermarket management which combines diversified staffing needs, the need for flexible nursing staff management inthe management of routine epidemic prevention and control, as well as nursing staff capacity development to meet the needs of nursing human resource management inthe current state of medical services.
分类: 天文学 >> 天文学 提交时间: 2024-03-29 合作期刊: 《Research in Astronomy and Astrophysics》
摘要: We report the confirmation of a sub-Saturn-size exoplanet, TOI-1194 b, with a mass of about MJ, and a very low mass companion star with a mass of about 96.5 ± 1.5 MJ, TOI-1251 B. Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite (TESS) are suitable for further follow-up observations by ground-based telescopes with small and medium apertures. The analysis is performed based on data from several telescopes worldwide, including telescopes in the Sino-German multiband photometric campaign, which aimed at confirming TESS Objects of Interest (TOIs) using ground-based small-aperture and medium-aperture telescopes, especially for long-period targets. TOI-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric data. We measure an orbital period of 2.310644 ± 0.000001 days, the radius is RJ and the amplitude of the RV curve is m s−1. TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data, whose orbital period is days, radius is RJ and amplitude of the RV curve is m s−1.
分类: 光学 >> 量子光学 提交时间: 2023-02-19
摘要: Nonlinear optics processes lie at the heart of photonics and quantum optics for their indispensable role in light sources and information processing. During the past decades, the three- and four-wave mixing ($\chi^{(2)}$ and $\chi^{(3)}$) effects have been extensively studied, especially in the micro-/nano-structures by which the photon-photon interaction strength is greatly enhanced. So far, the high-order nonlinearity beyond the $\chi^{(3)}$ has rarely been studied in dielectric materials due to their weak intrinsic nonlinear susceptibility, even in high-quality microcavities. Here, an effective five-wave mixing process ($\chi^{(4)}$) is synthesized for the first time, by incorporating $\chi^{(2)}$ and $\chi^{(3)}$ processes in a single microcavity. The coherence of the synthetic $\chi^{(4)}$ is verified by generating time-energy entangled visible-telecom photon-pairs, which requires only one drive laser at the telecom waveband. The photon pair generation rate from the synthetic process shows an enhancement factor over $500$ times upon intrinsic five-wave mixing. Our work demonstrates a universal approach of nonlinear synthesis via photonic structure engineering at the mesoscopic scale rather than material engineering, and thus opens a new avenue for realizing high-order optical nonlinearities and exploring novel functional photonic devices.
分类: 光学 >> 量子光学 提交时间: 2023-02-19
摘要: The nonlinear optical radiation of an integrated lithium niobate microcavity is demonstrated, which has been neglected in previous studies of nonlinear photonic devices. We find that the nonlinear coupling between confined optical modes on the chip and continuum modes in free space can be greatly enhanced on the platform of integrated microcavity, with feasible relaxation of the phase-matching condition. With an infrared pump laser, we observe the vertical radiation of second-harmonic wave at the visible band, which indicates a robust phase-matching-free chip-to-free-space frequency converter and also unveils an extra energy dissipation channel for integrated devices. Such an unexpected coherent nonlinear interaction between the free-space beam and the confined mode is also validated by the different frequency generation. Furthermore, based on the phase-matching-free nature of the nonlinear radiation, we build an integrated atomic gas sensor to characterize Rb isotopes with a single telecom laser. The unveiled mechanism of nonlinear optical radiation is universal for all dielectric photonic integrated devices, and provides a simple and robust chip-to-free-space as well as visible-to-telecom interface.