In this paper, the spontaneous Raman spectra and second harmonic generation (SHG) properties at 589 nm of a novel Raman crystal BaTeMo(2)O(9) (BTM) were investigated. The BTM crystal was cut along the type-II SHG phase-matching direction for the first-order Raman shift at 1178 nm to realize the SRS and SHG simultaneously. Pumped by a nanosecond 1064 nm laser source, a self-frequency-doubled BTM Raman laser operating at 589 nm has been demonstrated for the first time. At the pump pulse energy of 48 mJ, the maximum yellow laser output pulse energy of 5.6 mJ was obtained with an optical-to-optical conversion efficiency of 11.7%. Our results show that BTM crystal is one of the promising candidate Raman materials to generate yellow laser radiation.
Background Millions of cases of the novel coronavirus disease 2019 (COVID-19) have been reported in the world. Although it is known that the air travel has the potential to spread SARS-CoV-2, the risk of in-flight transmission is unknown.Methods We enrolled all passengers and crew suspected of being infected with SARS-CoV-2, who bounded for Beijing on international flights. We specified the characteristics of all confirmed cases of COVID-19 infection and utilized Wells-Riley equation to estimate the infectivity of COVID-19 during air travel.Results We screened 4492 passengers and crew with suspected COVID-19 infection, verified 161 confirmed cases (mean age 28.6 years), and traced two confirmed cases who may have been infected in the aircraft. The estimated infectivity was 375 quanta/h (range 274-476), while the effective infectivity was only 4 quanta/h (range 2-5). The risk of per-person infection during a 13 hours air travel in economy class was 0.56‰ (95% CI 0.41‰-0.72‰). Conclusion We found that the universal use of face masks on the flight, together with the plane's ventilation system, significantly decreased the infectivity of COVID-19.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.