We investigate the effects of spontaneously generated coherence （SGC） on both the steady and transient gain properties in a four-level inverted-Y-type atomic system in the presence of a weak probe, two strong cohere...We investigate the effects of spontaneously generated coherence （SGC） on both the steady and transient gain properties in a four-level inverted-Y-type atomic system in the presence of a weak probe, two strong coherent fields, and an incoherent pump. For the steady process, we find that the inversionless gain mainly origins from SGC. In particular, we can modulate the inversionless gain by changing the relative phase between the two fields. Moreover, the amplitude of the gain peak can be enhanced and the additional gain peak can appear by changing the detuning of the coupling field. As for the transient process, the transient gain properties can also be dramatically affected by the SGC. Compared to the case without SGC, the transient gain can be greatly enhanced with completely eliminated transient absorption by choosing the proper relative phase between the two fields. And the inverted-Y-type system with SGC can be simulated in both atomic and semiconductor quantum well systems avoiding the conditions of SGC.展开更多
We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields. We show that such a system emulates to a large degree a V-type atom with parallel dipole moments-th...We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields. We show that such a system emulates to a large degree a V-type atom with parallel dipole moments-the latter being a system that exhibits spontaneously generated coherence and can display ultrasharp spectral lines. We find a suitable energy scheme in a SSRb atom and experimentally observe the narrowing of the central peak in a rubidium atomic beam. The corresponding spectrum can convindngiy demonstrate the existence of spontaneously generated coherence.展开更多
A new simple pyrene-substituted acylhydrazone derivative, 4-（3,4-dioctyloxy） phenyl-l-pyrene acylhydrazone （PAH-8）, was designed and synthesized. The PAH-8 can form thermo-reversible organogel in DMSO, and shows g...A new simple pyrene-substituted acylhydrazone derivative, 4-（3,4-dioctyloxy） phenyl-l-pyrene acylhydrazone （PAH-8）, was designed and synthesized. The PAH-8 can form thermo-reversible organogel in DMSO, and shows gelation-induced enhanced fluorescence emission. Xerogel exhibits ribbon-like fibrous aggregates with widths of 0.5- 1 μm. The PAH-8 organogel indicates photo-responsive behaviors due to the trans-cis isomerizations of-C = N- bond upon exposure to visible or UV light. Upon visible light irradiation, the partial trans-cis isomerization of the -C=N- bond causes the fiber morphology to disappear, resulting in gel-sol transition, whereas the PAH-8 organogel exhibits few photoisomerizations from trans to cis transition without breakage of the gel state upon UV light irradiation.展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CB921603 and 2013CB933300)the National Natural Science Foundation of China(Grant Nos.11304308,61076064,and 61176046)+1 种基金Natural Science Foundation of Jilin Province,China(Grant Nos.20140101203JC)the Hundred Talents Program of the Chinese Academy of Sciences
文摘We investigate the effects of spontaneously generated coherence （SGC） on both the steady and transient gain properties in a four-level inverted-Y-type atomic system in the presence of a weak probe, two strong coherent fields, and an incoherent pump. For the steady process, we find that the inversionless gain mainly origins from SGC. In particular, we can modulate the inversionless gain by changing the relative phase between the two fields. Moreover, the amplitude of the gain peak can be enhanced and the additional gain peak can appear by changing the detuning of the coupling field. As for the transient process, the transient gain properties can also be dramatically affected by the SGC. Compared to the case without SGC, the transient gain can be greatly enhanced with completely eliminated transient absorption by choosing the proper relative phase between the two fields. And the inverted-Y-type system with SGC can be simulated in both atomic and semiconductor quantum well systems avoiding the conditions of SGC.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB921603)the National Natural Science Foundation of China (Grant Nos. 11074097,10904048,10974071,and 11004080)
文摘We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields. We show that such a system emulates to a large degree a V-type atom with parallel dipole moments-the latter being a system that exhibits spontaneously generated coherence and can display ultrasharp spectral lines. We find a suitable energy scheme in a SSRb atom and experimentally observe the narrowing of the central peak in a rubidium atomic beam. The corresponding spectrum can convindngiy demonstrate the existence of spontaneously generated coherence.
基金Supporting information for this article is available on the WWW under http：//dx.doi.org/10.1002/cjoc.201700388 or from the author.Acknowledgement This work was supported by the Natural Science Foundation of Jilin Province （20170101112JC） and Project 985-Automotive Engineering of Jilin University.
文摘A new simple pyrene-substituted acylhydrazone derivative, 4-（3,4-dioctyloxy） phenyl-l-pyrene acylhydrazone （PAH-8）, was designed and synthesized. The PAH-8 can form thermo-reversible organogel in DMSO, and shows gelation-induced enhanced fluorescence emission. Xerogel exhibits ribbon-like fibrous aggregates with widths of 0.5- 1 μm. The PAH-8 organogel indicates photo-responsive behaviors due to the trans-cis isomerizations of-C = N- bond upon exposure to visible or UV light. Upon visible light irradiation, the partial trans-cis isomerization of the -C=N- bond causes the fiber morphology to disappear, resulting in gel-sol transition, whereas the PAH-8 organogel exhibits few photoisomerizations from trans to cis transition without breakage of the gel state upon UV light irradiation.
