The direct excitation of CO2 using fast (nanosecond) and ultrafast (femtosecond) pulsed lasers was investigated.A gas reaction cell was used to excite CO2 in a 50:50 mixture of CO2 and CH4 using nano-and femtosecond l...The direct excitation of CO2 using fast (nanosecond) and ultrafast (femtosecond) pulsed lasers was investigated.A gas reaction cell was used to excite CO2 in a 50:50 mixture of CO2 and CH4 using nano-and femtosecond laser systems,to induce a reaction between these two compounds.FT-IR spectra showed that CO was formed using the nanosecond and femtosecond laser systems.It was also found that hydrocarbons,containing C-C bonds were formed.For both the nanosecond and femtosecond laser,it was found that more C-C higher hydrocarbons were formed after 5 h compared to 3 h of irradiation.Irradiation at pressures of 250,350 and 500 kPa with the femtosecond laser system showed the expected increase in the amount of CO formed with an increase in pressure.Results from this study showed that carbon dioxide and methane can be activated successfully using nanosecond laser pulses at 2000 nm and femtosecond laser pulses at 795 or 2000 nm and that these activated species react to form CO and C-C containing products.展开更多
Vector beams,non-separable in spatial mode and polarisation,have emerged as enabling tools in many diverse applications,from communication to imaging.This applicability has been achieved by sophisticated laser designs...Vector beams,non-separable in spatial mode and polarisation,have emerged as enabling tools in many diverse applications,from communication to imaging.This applicability has been achieved by sophisticated laser designs controlling the spin and orbital angular momentum,but so far is restricted to only two-dimensional states.Here we demonstrate the first vectorially structured light created and fully controlled in eight dimensions,a new state-of-the-art.We externally modulate our beam to control,for the frst time,the complete set of classical Greenberger-Horne-Zeilinger(GHZ)states in paraxial structured light beams,in analogy with high-dimensional multi-partite quantum entangled states,and introduce a new tomography method to verify their fidelity.Our complete theoretical framework reveals a rich parameter space for further extending the dimensionality and degrees of freedom,opening new pathways for vetorilly structured light in the classical and quantum regimes.展开更多
文摘The direct excitation of CO2 using fast (nanosecond) and ultrafast (femtosecond) pulsed lasers was investigated.A gas reaction cell was used to excite CO2 in a 50:50 mixture of CO2 and CH4 using nano-and femtosecond laser systems,to induce a reaction between these two compounds.FT-IR spectra showed that CO was formed using the nanosecond and femtosecond laser systems.It was also found that hydrocarbons,containing C-C bonds were formed.For both the nanosecond and femtosecond laser,it was found that more C-C higher hydrocarbons were formed after 5 h compared to 3 h of irradiation.Irradiation at pressures of 250,350 and 500 kPa with the femtosecond laser system showed the expected increase in the amount of CO formed with an increase in pressure.Results from this study showed that carbon dioxide and methane can be activated successfully using nanosecond laser pulses at 2000 nm and femtosecond laser pulses at 795 or 2000 nm and that these activated species react to form CO and C-C containing products.
基金Marie S.-Curie MULTIPLY Fellowship (GA713694)National Key Research and Development Program of China (2017YFB1104500)+2 种基金National Natural Science Foundation of China (61975087)Natural Science Foundation of Beijing Municipality (4172030)Beijing Young Talents Support Project (2017000020124G044).
文摘Vector beams,non-separable in spatial mode and polarisation,have emerged as enabling tools in many diverse applications,from communication to imaging.This applicability has been achieved by sophisticated laser designs controlling the spin and orbital angular momentum,but so far is restricted to only two-dimensional states.Here we demonstrate the first vectorially structured light created and fully controlled in eight dimensions,a new state-of-the-art.We externally modulate our beam to control,for the frst time,the complete set of classical Greenberger-Horne-Zeilinger(GHZ)states in paraxial structured light beams,in analogy with high-dimensional multi-partite quantum entangled states,and introduce a new tomography method to verify their fidelity.Our complete theoretical framework reveals a rich parameter space for further extending the dimensionality and degrees of freedom,opening new pathways for vetorilly structured light in the classical and quantum regimes.
