Narrow band amplification of light carrying orbital angular momentum

We report on the amplification of an optical vortex beam carrying orbital angular momentum via induced narrow Raman gain in an ensemble of cold cesium atoms. A 20\% single-pass Raman gain of a weak vortex signal field is observed with a spectral width of order of 1 MHz, much smaller than the natural width, demonstrating that the amplification process preserves the phase structure of the vortex beam. The gain is observed in the degenerated two-level system associated with the hyperfine transition $6S_{1/2}(F=3)\leftrightarrow 6P_{3/2}(F^{\prime}=2)$ of cesium. Our experimental observations are explained with a simple theoretical model based on a three-level $\Lambda$ system interacting coherently with the weak Laguerre-Gauss field and a strong coupling field, including an incoherent pumping rate between the two degenerate ground-states.Comment: 9 pages, 4 figure

Effective Communication of 4-H Program Essentials to 4-H Families

Youths and parents in the California 4-H program have reported issues with communication and challenges in understanding the program. As a result, we developed a family handbook and other supporting documents to help youths and parents navigate the California 4-H program. This article addresses the development, dissemination, and reach of the handbook. Additionally, the article discusses future directions and implications for other Extension programs

Relação entre a qualidade de semente e densidade de plantio na produção de milho.

Trabalho apresentado no X Congresso Brasileiro de Sementes

Influência do tipo de corante na análise de danos mecânicos em sementes de milho (Zea mays L.).

xTrabalho apresentado no X Congresso Brasileiro de Sementes, 1997