The beam divergence effects of the input pump laser on a high power nanosecond optical parametric oscillator （OPO） have been numerically simulated. The OPO conversion efficiency is affected due to the angular deviat...The beam divergence effects of the input pump laser on a high power nanosecond optical parametric oscillator （OPO） have been numerically simulated. The OPO conversion efficiency is affected due to the angular deviation of real laser beams from ideal phase matching conditions. Our theoretical model is based on the decomposition of the Gaussian beam and assumes each component has a single deviation angle and thus a particular wave vector mismatch. We take into account the variable intensity profile in the spatial and temporal domains of the Gaussian beam, the pump depletion effects for large-signal processes as well as the oscillatory effects of the three waves. Two nonlinear crystals β-BaB2O4 （BBO） and LiB305 （LBO） have been investigated in detail. The results indicate that the degree of beam divergence strongly influences the maximum pump intensity, optimum crystal length and OPO conversion efficiency. The impact of beam divergence is much more severe in the case of critical phase-matching for BBO than in the case of non-critical phase-matching for LBO. The results provide a way to choose the optimum parameters for a high power ns OPO such as the nonlinear material, the crystal length and the pump intensity, etc. Good agreement is obtained with our experimental results.展开更多
Studies from behavioral economics show that the subjective prospect value of money has diminishing sensitivity to losses/gains,represented by an S-shape,and this has been applied in representing the subjective prospec...Studies from behavioral economics show that the subjective prospect value of money has diminishing sensitivity to losses/gains,represented by an S-shape,and this has been applied in representing the subjective prospect value of time in many transportation studies such as travel behavior modeling and network equilibrium.In this study,we demonstrate that the prospect value of time has an increasing sensitivity to losses/gains and can be represented by anϨ-shape,which contrasts that of money.We further explain the rationality of this surprising finding based on psychological and behavioral theories and discuss extensive practical implications.The correlations between sensitivities to gains and losses in terms of magnitude are revealed as well to shed light on potential underlying correlated behavioral principles.Substantial loss-aversion features are observed in the empirical analysis,supporting endowment effects.Implications of the findings on decision-making and other areas that utilize time as a key indicator have been discussed.The findings may revolutionize many research areas that utilize time as a key indicator such as transportation engineering.展开更多
文摘The beam divergence effects of the input pump laser on a high power nanosecond optical parametric oscillator （OPO） have been numerically simulated. The OPO conversion efficiency is affected due to the angular deviation of real laser beams from ideal phase matching conditions. Our theoretical model is based on the decomposition of the Gaussian beam and assumes each component has a single deviation angle and thus a particular wave vector mismatch. We take into account the variable intensity profile in the spatial and temporal domains of the Gaussian beam, the pump depletion effects for large-signal processes as well as the oscillatory effects of the three waves. Two nonlinear crystals β-BaB2O4 （BBO） and LiB305 （LBO） have been investigated in detail. The results indicate that the degree of beam divergence strongly influences the maximum pump intensity, optimum crystal length and OPO conversion efficiency. The impact of beam divergence is much more severe in the case of critical phase-matching for BBO than in the case of non-critical phase-matching for LBO. The results provide a way to choose the optimum parameters for a high power ns OPO such as the nonlinear material, the crystal length and the pump intensity, etc. Good agreement is obtained with our experimental results.
文摘Studies from behavioral economics show that the subjective prospect value of money has diminishing sensitivity to losses/gains,represented by an S-shape,and this has been applied in representing the subjective prospect value of time in many transportation studies such as travel behavior modeling and network equilibrium.In this study,we demonstrate that the prospect value of time has an increasing sensitivity to losses/gains and can be represented by anϨ-shape,which contrasts that of money.We further explain the rationality of this surprising finding based on psychological and behavioral theories and discuss extensive practical implications.The correlations between sensitivities to gains and losses in terms of magnitude are revealed as well to shed light on potential underlying correlated behavioral principles.Substantial loss-aversion features are observed in the empirical analysis,supporting endowment effects.Implications of the findings on decision-making and other areas that utilize time as a key indicator have been discussed.The findings may revolutionize many research areas that utilize time as a key indicator such as transportation engineering.
