Existence of dark stuff （dark matter ＋ dark energy） is overwhelming. The WIMPs （Weakly interacting massive particles） hypnotized for the existence of dark stuffhave not been detected. We are exploring the linkage...Existence of dark stuff （dark matter ＋ dark energy） is overwhelming. The WIMPs （Weakly interacting massive particles） hypnotized for the existence of dark stuffhave not been detected. We are exploring the linkage of our quantum mechanical probabilistic and gravity to the issue of dark stuff in the universe. Our new horizon gives us a deeper insight, pointing to small black holes as candidates of dark stuff. We invoke the spooky nature of quantum physics which gets spookier to hold the universe together.展开更多
In this article, we report on a ring-cavity diode laser configuration, which has more features compared to the standing-wave external-cavity diode lasers. First, a transmission grating will be used, and the ring-cavit...In this article, we report on a ring-cavity diode laser configuration, which has more features compared to the standing-wave external-cavity diode lasers. First, a transmission grating will be used, and the ring-cavity laser output will be the zero-order output from the transmission grating. Therefore, unlike the standing-wave external cavity diode lasers, the output direction of this ring-cavity laser does not depend on the laser's frequency. Second, since it is a ring-cavity laser, it can avoid the local heating caused by the antinodes of the standing-wave lasers. Moreover, because this ring-cavity will allow the laser beam to pass the transmission grating two times, it is expected that this will ultimately result in a narrower linewidth compared to the external-cavity standing-wave lasers with the same cavity length.展开更多
A new conception of nano-laser is proposed in which depending on the size of nano-clusters (silicon quantum dots (QD)), the pumping level of laser can be tuned by the quantum confinement (QC) effect, and the populatio...A new conception of nano-laser is proposed in which depending on the size of nano-clusters (silicon quantum dots (QD)), the pumping level of laser can be tuned by the quantum confinement (QC) effect, and the population inversion can be formed between the valence band and the localized states produced from the surface bonds. The nano-laser belongs to the emission of type Ⅱ. The peaks of stimulated emission are observed at 605 nm and 693 nm. Through the micro-cavity of nano-laser, a full width at half maximum of the peak at 693 nm can reach to 0.5 nm. The theoretical model and the experimental results indicate that it is a necessary condition for setting up nano-laser that the smaller size of nano-clusters (d<3 nm) can make the localized states into band gap below the conduction band opened and the states of conduction band become the pumping level of nano-laser. The emission energy of nano-laser will be limited in the range of 1.7～2.3 eV generally due to the position of the localized states in gap, which is good in agreement between the experiments and the theory.展开更多
The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, a Si-O-Si bridge bond on curved surface provides the localized ...The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, a Si-O-Si bridge bond on curved surface provides the localized levels in band gap and its bonding energy is shallower than that on facet. The red-shifting of PL spectra on smaller silicon quantum dots can be explained by curved surface effect. Experiments demonstrate that silicon quantum dots are activated for emission due to the localized levels provided in curved surface effect.展开更多
Density functional theory (DFT) calculations were employed to investigate the electronic properties of an H-atom terminated graphene patch (hydrographene) smaller than a rhombic C96H26 structure with zigzag edges. Dep...Density functional theory (DFT) calculations were employed to investigate the electronic properties of an H-atom terminated graphene patch (hydrographene) smaller than a rhombic C96H26 structure with zigzag edges. Depending on shapes and sizes of hydrographenes, some hydrographenes have the triplet ground state where unpaired electrons are localized on their zigzag edges. The stability of the triplet spin state is diminished, decreasing the hydrographene sizes. The existence of the localized spin densities allows triplet dioxgen to bind into a hydrographene. According to the DFT calculations, the energetics of the dioxygen bindings is negatively influenced by downsizing hydrographenes, as well as depends on their shapes. The size-and shape-dependences of the dioxygen bindings reflect from the stability of the triplet state of a hydrographene, because its localized unpaired electrons can be utilized to be attached to an unpaired electron of triplet dioxygen.展开更多
文摘Existence of dark stuff （dark matter ＋ dark energy） is overwhelming. The WIMPs （Weakly interacting massive particles） hypnotized for the existence of dark stuffhave not been detected. We are exploring the linkage of our quantum mechanical probabilistic and gravity to the issue of dark stuff in the universe. Our new horizon gives us a deeper insight, pointing to small black holes as candidates of dark stuff. We invoke the spooky nature of quantum physics which gets spookier to hold the universe together.
文摘In this article, we report on a ring-cavity diode laser configuration, which has more features compared to the standing-wave external-cavity diode lasers. First, a transmission grating will be used, and the ring-cavity laser output will be the zero-order output from the transmission grating. Therefore, unlike the standing-wave external cavity diode lasers, the output direction of this ring-cavity laser does not depend on the laser's frequency. Second, since it is a ring-cavity laser, it can avoid the local heating caused by the antinodes of the standing-wave lasers. Moreover, because this ring-cavity will allow the laser beam to pass the transmission grating two times, it is expected that this will ultimately result in a narrower linewidth compared to the external-cavity standing-wave lasers with the same cavity length.
基金Support from the National Natural Science Foundation of China ( Grant No.10764002,60966002,11264007)the National Key Laboratory of Surface Physics in Fudan University
文摘A new conception of nano-laser is proposed in which depending on the size of nano-clusters (silicon quantum dots (QD)), the pumping level of laser can be tuned by the quantum confinement (QC) effect, and the population inversion can be formed between the valence band and the localized states produced from the surface bonds. The nano-laser belongs to the emission of type Ⅱ. The peaks of stimulated emission are observed at 605 nm and 693 nm. Through the micro-cavity of nano-laser, a full width at half maximum of the peak at 693 nm can reach to 0.5 nm. The theoretical model and the experimental results indicate that it is a necessary condition for setting up nano-laser that the smaller size of nano-clusters (d<3 nm) can make the localized states into band gap below the conduction band opened and the states of conduction band become the pumping level of nano-laser. The emission energy of nano-laser will be limited in the range of 1.7～2.3 eV generally due to the position of the localized states in gap, which is good in agreement between the experiments and the theory.
基金Support from the National Natural Science Foundation of China (Grant No.60966002,11264007)the National Key Laboratory of Surface Physics in Fudan University
文摘The calculation results show that the bonding energy and electronic states of silicon quantum dots are different on various curved surfaces, for example, a Si-O-Si bridge bond on curved surface provides the localized levels in band gap and its bonding energy is shallower than that on facet. The red-shifting of PL spectra on smaller silicon quantum dots can be explained by curved surface effect. Experiments demonstrate that silicon quantum dots are activated for emission due to the localized levels provided in curved surface effect.
基金supported by a Grant-in-Aid for Young Scientists (B) from the Japan Society for the Promotion of Science (T. Y. at the Kyoto Institute of Technology) (22710088)a Grant-in-Aid for Scientific Research (C) from JSPS (T. Y. at the Kyoto Institute of Technology) (23560934)
文摘Density functional theory (DFT) calculations were employed to investigate the electronic properties of an H-atom terminated graphene patch (hydrographene) smaller than a rhombic C96H26 structure with zigzag edges. Depending on shapes and sizes of hydrographenes, some hydrographenes have the triplet ground state where unpaired electrons are localized on their zigzag edges. The stability of the triplet spin state is diminished, decreasing the hydrographene sizes. The existence of the localized spin densities allows triplet dioxgen to bind into a hydrographene. According to the DFT calculations, the energetics of the dioxygen bindings is negatively influenced by downsizing hydrographenes, as well as depends on their shapes. The size-and shape-dependences of the dioxygen bindings reflect from the stability of the triplet state of a hydrographene, because its localized unpaired electrons can be utilized to be attached to an unpaired electron of triplet dioxygen.
