Light amplification due to two-beam coupling is realized in doped polymethyl methacrylate （PMMA） glasses. A coupling gain as large as 14 cm^-1 is obtained. The dynamic behaviour of absorption and light-induced scatt...Light amplification due to two-beam coupling is realized in doped polymethyl methacrylate （PMMA） glasses. A coupling gain as large as 14 cm^-1 is obtained. The dynamic behaviour of absorption and light-induced scattering due to the process of photopolymerization are also studied. The results show that the amplification and its dynamic process enable possible applications of PMMA in optical devices.展开更多
Random lasing was experimentally investigated in pyrromethene 597-doped strongly disordered chiral liquid crystals (CLCs) composed of the nematic liquid crystal SLC1717 and the chiral agent CB15. The concentration of ...Random lasing was experimentally investigated in pyrromethene 597-doped strongly disordered chiral liquid crystals (CLCs) composed of the nematic liquid crystal SLC1717 and the chiral agent CB15. The concentration of the chiral agent tuned the bandgap, and disordered CLC microdomains were achieved by fast quenching of the mixture from the isotropic to the cholesteric phase. Random lasing and band edge lasing were observed synchronously, and their behavior changed with the spectral location of the bandgap. The emission band for band edge lasing shifted with the change of the bandgap, while the emission band for random lasing remained practically constant. The results show that the threshold for random lasing sharply decreases if the CLC selective reflection band overlaps with the fluorescence peak of the dye molecules and if the band edge coincides at the same time with the excitation wavelength.展开更多
The phase shifts of the extinction and refractive index gratings to the illumination pattern are revealed in doped polymethyl methacrylate （PMMA）. The dynamic process of these shifts is studied via two-wave coupling...The phase shifts of the extinction and refractive index gratings to the illumination pattern are revealed in doped polymethyl methacrylate （PMMA）. The dynamic process of these shifts is studied via two-wave coupling at 351 nm. It is shown that these shifts are from the strain and the shrinkage inside the sample and accompanied with the photo-repolymerization process during the building process of the holographic grating. Such shifts will cause obvious energy exchange between the two recording beams and enough attention should be paid to the nonlocal property of the holographic gratings of the material in the application.展开更多
基金supported by the National Natural Science Foundation of China(10979029,11204148 and 51172111)the Fundof National Engineering Research Center for Optoelectronic Crystalline Materials(2007k08)
基金Supported by the Ministry of Education of China under Grant Nos 105048 and 704012, the National Natural Science Foundation of China under Grant Nos 10604033 and 10334010, the Cultivation Fund of the Key Scientific and Technical Innovation Project, the Key International S＆T Cooperation Project （2005DFA10170）, the Programme for Changjiang Scholars and Innovative Research Team in University （PCSIRT）, the National Basic Research Programme of China under Grant No 2007CB307002）, the 111 Project the Ministry of Education of China under Grant No B07013, and the Scientific-Technical Cooperation Project of （DAD （VII-B-7）.
文摘Light amplification due to two-beam coupling is realized in doped polymethyl methacrylate （PMMA） glasses. A coupling gain as large as 14 cm^-1 is obtained. The dynamic behaviour of absorption and light-induced scattering due to the process of photopolymerization are also studied. The results show that the amplification and its dynamic process enable possible applications of PMMA in optical devices.
基金National Key Research and Development Program of China(2017YFA0303800)National Natural Science Foundation of China(91750204,11674182)+4 种基金111Project(B07013)Natural Science Foundation of Tianjin City(17JCYBJC16700)Slovenian Research Agency(ARRS,Research Program P1-0192)Project of National Academy of Sciences of Ukraine(0117U002612)Projects of National Academy of Sciences of Ukraine(V-197,VC-202)。
文摘Random lasing was experimentally investigated in pyrromethene 597-doped strongly disordered chiral liquid crystals (CLCs) composed of the nematic liquid crystal SLC1717 and the chiral agent CB15. The concentration of the chiral agent tuned the bandgap, and disordered CLC microdomains were achieved by fast quenching of the mixture from the isotropic to the cholesteric phase. Random lasing and band edge lasing were observed synchronously, and their behavior changed with the spectral location of the bandgap. The emission band for band edge lasing shifted with the change of the bandgap, while the emission band for random lasing remained practically constant. The results show that the threshold for random lasing sharply decreases if the CLC selective reflection band overlaps with the fluorescence peak of the dye molecules and if the band edge coincides at the same time with the excitation wavelength.
基金supported by the Tianjin Natural Science Foundation(No.07JCYBJC16600)the National Natural Science Foundation of China(Nos.10874093, 10604033,and 10804055)+3 种基金the National Basic Research Program of China(No.2007CB307002)the Key International S&T Cooperation Project(No.2005DFA10170) the"111"Project of China(No.B07013)the National"973"Program of China(No.2007CB613203)
文摘The phase shifts of the extinction and refractive index gratings to the illumination pattern are revealed in doped polymethyl methacrylate （PMMA）. The dynamic process of these shifts is studied via two-wave coupling at 351 nm. It is shown that these shifts are from the strain and the shrinkage inside the sample and accompanied with the photo-repolymerization process during the building process of the holographic grating. Such shifts will cause obvious energy exchange between the two recording beams and enough attention should be paid to the nonlocal property of the holographic gratings of the material in the application.
