Polymeric semiconductors spin-coated onto the photoresist grating form discontinuously distributed flocci,which do not fill grating grooves with nanoscale widths.Thus,the polymer layer neither forms a continuous gain ...Polymeric semiconductors spin-coated onto the photoresist grating form discontinuously distributed flocci,which do not fill grating grooves with nanoscale widths.Thus,the polymer layer neither forms a continuous gain channel nor creates a waveguide that enhances the distributed feedback(DFB)mechanism provided by the grating structures.This is verified by the microscopic and spectroscopic investigations on the topographic surface of the polymer-covered grating as it is etched layer by layer using oxygen plasma.This gives more insights into the mechanisms involved in optically pumped polymer lasers and provides new guidance for constructing DFB lasers.展开更多
The wavelength variation of a laser-dye-type random laser is observed experimentally.It is found that the emitting wavelength of a random laser changes with the change of concentration of the gain material.Also,the ac...The wavelength variation of a laser-dye-type random laser is observed experimentally.It is found that the emitting wavelength of a random laser changes with the change of concentration of the gain material.Also,the actual radiation wavelength is influenced by the pumping rate of the source,the cavity competition and the concentration of scatterers.展开更多
We demonstrate theoretically and experimentally the difference between the band compression mechanisms of plasmonic gratings and plasmonic heterogratings.The plasmonic grating can pick out a fixed polarization band-wi...We demonstrate theoretically and experimentally the difference between the band compression mechanisms of plasmonic gratings and plasmonic heterogratings.The plasmonic grating can pick out a fixed polarization band-width with changing the incidence angle,while the plasmonic heterograting composed of two different nanograt-ings can pick out a tunable bandwidth with changing the incidence angle and the period ratio of two gratings.The range of the plasmonic resonances of the heterograting is about 30%wider than that of a conventional grating.Thus,the plasmonic heterograting can work efficiently in a wider wavelength range.Moreover,high polarization extinction ratio is achieved in these plasmonic devices.This gives more insights into the mechanisms in plasmonic filters and is helpful to promote the actual applications.展开更多
基金Supported by the National Natural Science Foundation of China(11074018,11104007)the Research Fund for the Doctoral Program of Higher Education of China(RFDP,20091103110012)the Beijing Educational Commission(KM201210005034).
文摘Polymeric semiconductors spin-coated onto the photoresist grating form discontinuously distributed flocci,which do not fill grating grooves with nanoscale widths.Thus,the polymer layer neither forms a continuous gain channel nor creates a waveguide that enhances the distributed feedback(DFB)mechanism provided by the grating structures.This is verified by the microscopic and spectroscopic investigations on the topographic surface of the polymer-covered grating as it is etched layer by layer using oxygen plasma.This gives more insights into the mechanisms involved in optically pumped polymer lasers and provides new guidance for constructing DFB lasers.
基金Supported by the National Natural Science Foundation of China under Grant Nos.60677006 and 11074024.
文摘The wavelength variation of a laser-dye-type random laser is observed experimentally.It is found that the emitting wavelength of a random laser changes with the change of concentration of the gain material.Also,the actual radiation wavelength is influenced by the pumping rate of the source,the cavity competition and the concentration of scatterers.
基金Supported by the National Basic Research Program of China(2013CB922404)the National Natural Science Foundation of China(11104007 and 11274031)+2 种基金the Beijing Natural Science Foundation(1132004,4133082)the Beijing Educational Commission(KM201210005034)Beijing Nova Program(2012009).
文摘We demonstrate theoretically and experimentally the difference between the band compression mechanisms of plasmonic gratings and plasmonic heterogratings.The plasmonic grating can pick out a fixed polarization band-width with changing the incidence angle,while the plasmonic heterograting composed of two different nanograt-ings can pick out a tunable bandwidth with changing the incidence angle and the period ratio of two gratings.The range of the plasmonic resonances of the heterograting is about 30%wider than that of a conventional grating.Thus,the plasmonic heterograting can work efficiently in a wider wavelength range.Moreover,high polarization extinction ratio is achieved in these plasmonic devices.This gives more insights into the mechanisms in plasmonic filters and is helpful to promote the actual applications.
