The applicability of diffusion theory for the determination of tissue optical properties from steady-state diffuse reflectance is investigated.Analytical expressions from diffusion theory using the two most commonly a...The applicability of diffusion theory for the determination of tissue optical properties from steady-state diffuse reflectance is investigated.Analytical expressions from diffusion theory using the two most commonly assumed boundary conditions at the air-tissue interface and the two definitions of the diffusion coefficient are compared with Monte Carlo simulations.The effects of the choice of the boundary conditions and diffusion coefficients on the accuracy of the findings for the optical parameters are quantified.and criteria for accurate curve-fitting algorithms are developed.It is shown that the error in deriving the optical coefficients is considerably smaller for the solution which uses the extrapolated boundary condition and the diffusion coefficient independence of absorption coeffcient,compared to the other three solutions.展开更多
The phonon-assisted quantum cutting (PQC) model is presumed to clarify the red up-conversion luminescence process in Er^3+ /yb^3+ co-doped glass ceramics by the excitation and emission spectra. The red up-conversion l...The phonon-assisted quantum cutting (PQC) model is presumed to clarify the red up-conversion luminescence process in Er^3+ /yb^3+ co-doped glass ceramics by the excitation and emission spectra. The red up-conversion luminescence of Er^3+ ions mainly comes from three-photon absorption by the PQC process when the rare earth ions are doped in the g/ass ceramics and excited by 98Ohm pumped-laser. Er^3+ ions absorb three-photons and relax to the ^4G11/2 state and then emit red up-conversion luminescence by the PQC process. The factor coefficient for the relation of pump-laser power and up-conversion intensity (P-I) is found by the analysis of excitation spectra of the red luminescence, which plays a major role to understand the true red up-conversion luminescence process. The new P-I relation is explained by the model of PQC.展开更多
We report a cw Er^3+ :Yb^3+ co-doped phosphate glass laser pumped by a laser diode. The maximum output power of 78.3mW and a slope efficiency of 15.25% were achieved. The laser spectral region was from 1532nm to 15...We report a cw Er^3+ :Yb^3+ co-doped phosphate glass laser pumped by a laser diode. The maximum output power of 78.3mW and a slope efficiency of 15.25% were achieved. The laser spectral region was from 1532nm to 1535nm, with the peak laser wavelength at 1534nm. The laser modes and time stabillty were also measured.The thermal effect had little influence on the output in our experiment.展开更多
We found that the bacteriorhodopsin (bR) film has a special property of complementary suppression modulated transmission (CSMT). The yellow and the blue beams can be suppressed mutually when both the beams illumlnate ...We found that the bacteriorhodopsin (bR) film has a special property of complementary suppression modulated transmission (CSMT). The yellow and the blue beams can be suppressed mutually when both the beams illumlnate the bR film simultaneously. When the blue beam carrying an image with a bright-background noise illuminates on the bR film and then a yellow beam with uniform intensity distribution illuminates the same area, the bright-background can be removed due to the CSMT. In our demonstration, the pattern model is letters “VLSF” with ground noise of small words and the ground noise is removed from the pattern by the new optical filter.展开更多
Optical nonlinearities of new organophosphorus fullerene derivative were determined by the Z-scan method with a pulsed Q-switch Nd:YAG laser at 532nm. The experimental results demonstrated that the derivative has much...Optical nonlinearities of new organophosphorus fullerene derivative were determined by the Z-scan method with a pulsed Q-switch Nd:YAG laser at 532nm. The experimental results demonstrated that the derivative has much larger excited-states nonlinear absorption and nonlinear refraction than C60. A five-level model was utilized to fit the experimental data, and a good agreement is reached. Some parameters such as excited-state absorption cross and refraction cross were obtained. To our knowledge, the excited-state cross section of new organophosphorus fullerene derivative and its effective ratio to the ground-state cross section are the largest values among the fullerene derivatives reported to date.展开更多
We apply a new method consisting of a coordinate transformation and two-step scheme to simulate numerically Zscan characteristics of a nonlinear medium. A comparison of numerical results obtained by this new method wi...We apply a new method consisting of a coordinate transformation and two-step scheme to simulate numerically Zscan characteristics of a nonlinear medium. A comparison of numerical results obtained by this new method with those by the conventional numerical method is made. The results show that the new scheme yields a large, orders-展开更多
In this paper,we study quadrature squeezings of two Bose-Einstein condensates with collision and nonclassical properties of pair entanglement in four wave mixing in Bose-Einstein condensates.With the aid of a numerica...In this paper,we study quadrature squeezings of two Bose-Einstein condensates with collision and nonclassical properties of pair entanglement in four wave mixing in Bose-Einstein condensates.With the aid of a numerical method,we find that the two modes(pair entanglement modes)a1 and a2 may exhibit quadrature squeezing,in which they are affected by the initial phase.It is shown that the two pump modes exhibit the same super-Poissonian distribution.The analysis for the mode-mode correlation shows that there always exists a violation of the Cauchy-Schwartz inequality,which means that correlation between the two pump modes is nonclassical.展开更多
文摘The applicability of diffusion theory for the determination of tissue optical properties from steady-state diffuse reflectance is investigated.Analytical expressions from diffusion theory using the two most commonly assumed boundary conditions at the air-tissue interface and the two definitions of the diffusion coefficient are compared with Monte Carlo simulations.The effects of the choice of the boundary conditions and diffusion coefficients on the accuracy of the findings for the optical parameters are quantified.and criteria for accurate curve-fitting algorithms are developed.It is shown that the error in deriving the optical coefficients is considerably smaller for the solution which uses the extrapolated boundary condition and the diffusion coefficient independence of absorption coeffcient,compared to the other three solutions.
文摘The phonon-assisted quantum cutting (PQC) model is presumed to clarify the red up-conversion luminescence process in Er^3+ /yb^3+ co-doped glass ceramics by the excitation and emission spectra. The red up-conversion luminescence of Er^3+ ions mainly comes from three-photon absorption by the PQC process when the rare earth ions are doped in the g/ass ceramics and excited by 98Ohm pumped-laser. Er^3+ ions absorb three-photons and relax to the ^4G11/2 state and then emit red up-conversion luminescence by the PQC process. The factor coefficient for the relation of pump-laser power and up-conversion intensity (P-I) is found by the analysis of excitation spectra of the red luminescence, which plays a major role to understand the true red up-conversion luminescence process. The new P-I relation is explained by the model of PQC.
文摘We report a cw Er^3+ :Yb^3+ co-doped phosphate glass laser pumped by a laser diode. The maximum output power of 78.3mW and a slope efficiency of 15.25% were achieved. The laser spectral region was from 1532nm to 1535nm, with the peak laser wavelength at 1534nm. The laser modes and time stabillty were also measured.The thermal effect had little influence on the output in our experiment.
文摘We found that the bacteriorhodopsin (bR) film has a special property of complementary suppression modulated transmission (CSMT). The yellow and the blue beams can be suppressed mutually when both the beams illumlnate the bR film simultaneously. When the blue beam carrying an image with a bright-background noise illuminates on the bR film and then a yellow beam with uniform intensity distribution illuminates the same area, the bright-background can be removed due to the CSMT. In our demonstration, the pattern model is letters “VLSF” with ground noise of small words and the ground noise is removed from the pattern by the new optical filter.
文摘Optical nonlinearities of new organophosphorus fullerene derivative were determined by the Z-scan method with a pulsed Q-switch Nd:YAG laser at 532nm. The experimental results demonstrated that the derivative has much larger excited-states nonlinear absorption and nonlinear refraction than C60. A five-level model was utilized to fit the experimental data, and a good agreement is reached. Some parameters such as excited-state absorption cross and refraction cross were obtained. To our knowledge, the excited-state cross section of new organophosphorus fullerene derivative and its effective ratio to the ground-state cross section are the largest values among the fullerene derivatives reported to date.
文摘We apply a new method consisting of a coordinate transformation and two-step scheme to simulate numerically Zscan characteristics of a nonlinear medium. A comparison of numerical results obtained by this new method with those by the conventional numerical method is made. The results show that the new scheme yields a large, orders-
文摘In this paper,we study quadrature squeezings of two Bose-Einstein condensates with collision and nonclassical properties of pair entanglement in four wave mixing in Bose-Einstein condensates.With the aid of a numerical method,we find that the two modes(pair entanglement modes)a1 and a2 may exhibit quadrature squeezing,in which they are affected by the initial phase.It is shown that the two pump modes exhibit the same super-Poissonian distribution.The analysis for the mode-mode correlation shows that there always exists a violation of the Cauchy-Schwartz inequality,which means that correlation between the two pump modes is nonclassical.
