We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
AIM:To compare the corneal backward light scattering values in type 2 diabetes mellitus(DM)patients with those of age and sex-matched healthy controls.METHODS:The study included 30 patients(30 eyes)with type 2 DM and ...AIM:To compare the corneal backward light scattering values in type 2 diabetes mellitus(DM)patients with those of age and sex-matched healthy controls.METHODS:The study included 30 patients(30 eyes)with type 2 DM and 30 control subjects(30 eyes).Duration of diabetes,most recent hemoglobin A1c levels,along with the status of diabetic retinopathy,and existing medical treatment of all subjects were recorded.All subjects underwent a complete ophthalmologic examination.In addition,backward light scattering(densitometry)was measured to assess changes in corneal transparency using tomography(Pentacam HR).RESULTS:The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females.The age was 50.40±7.80y(range:40-68y)of the diabetic group and 49.30±9.50y(rang:40-73y)of control group.The diabetic group demonstrated significantly higher mean densitometry values of the anterior(6-10 mm)zone(P=0.047),the total anterior layer(P=0.036)and the total cornea(P=0.043)than control group.The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration.CONCLUSION:Diabetic group has higher densitometry in anterior corneal(6-10 mm)zone,total anterior cornea,and total cornea and with no correlation with hemoglobin A1c levels and DM duration.展开更多
Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of supr...Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of suprathermal hot electrons under interaction conditions envisaged for direct-drive schemes for inertial confinement fusion.Nonetheless,SSRS remains to date one of the least understood parametric instabilities.Here,we report the first angularly and spectrally resolved measurements of scattered light at laser intensities relevant for the shock ignition scheme(I×10^(16)W/cm^(2)),showing significant SSRS growth in the direction perpendicular to the laser polarization.Modification of the focal spot shape and orientation,obtained by using two different random phase plates,and of the density gradient of the plasma,by utilizing exploding foil targets of different thicknesses,clearly reveals a different dependence of backward SRS(BSRS)and SSRS on experimental parameters.While convective BSRS scales with plasma density scale length,as expected by linear theory,the growth of SSRS depends on the spot extension in the direction perpendicular to laser polarization.Our analysis therefore demonstrates that under current experimental conditions,with density scale lengths L_(n)≈60–120μm and spot sizes FWHM≈40–100μm,SSRS is limited by laser beam size rather than by the density scale length of the plasma.展开更多
Crossed beams scattering study was carried out on the F＋HD→DF＋H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured,...Crossed beams scattering study was carried out on the F＋HD→DF＋H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured, with partial rotational state resolution, at eight collision energies in the range of 2.51-5.60 kJ/mol. Experimental results indicated that the product angular distributions are predominantly backward scattered. As the collision energy increases, the backward scattered peak becomes broader gradually. Dependence of product vibration branching ratios on the collision energy was also determined. The experimental results show that the DF products are highly inverted in the vibrational state distribution and the DF （v＇=3） product is the most populated state. Furthermore, the DF （v＇=l） product has also been observed at collision energy above 3.97 kJ/mol.展开更多
The entangled orbital angular momentum(OAM)photons propagating across a weakly turbulent atmosphere are investigated.Here,the paper uses the single-phase screen model based on the Kolmogorov theory of turbulence,and f...The entangled orbital angular momentum(OAM)photons propagating across a weakly turbulent atmosphere are investigated.Here,the paper uses the single-phase screen model based on the Kolmogorov theory of turbulence,and focuses on the influence of the backward scattering on OAM evolution.The results indicate that backward scattering plays an important role in the analysis of OAM entanglement evolution in the turbulent atmosphere.It cannot be negligible especially for higher-order OAM mode.Moreover,when OAM mode is greater than 4,entangled photon pairs composed of higher OAM modes are not more robust in turbulence within the weak scintillation regime.These results will be useful in future investigations of OAM-based optical wave propagation through turbulent atmosphere.展开更多
Passive daytime radiative cooling(PDRC)exhibits efficient cooling performance to reduce global fossil energy consumption and has attracted enormous interest.An efficient PDRC technology for achieving daytime subambien...Passive daytime radiative cooling(PDRC)exhibits efficient cooling performance to reduce global fossil energy consumption and has attracted enormous interest.An efficient PDRC technology for achieving daytime subambient cooling is supposed to exhibit ultra-high solar reflectivity and infrared emissivity within atmospheric windows,among which ultra-high solar reflectivity is the principal property.In most PDRC technologies,spherical particles are selected as scatterers to achieve high solar reflectivity because the Mie scattering effect of spherical scatterers can provide a high scattering efficiency.However,the weak backward scattering of spherical scatterers remains a drawback.In this study,several nonspherical scatterers with strong backward scattering are introduced and researched systematically.The numerical analysis results indicate that pyramidal scatterers provide the strongest backward scattering and square/circular scatterers exhibit the highest scattering efficiency.Besides,by considering scattering efficiency and asymmetry factor comprehensively,a dimensionless evaluation parameter is proposed,which can be employed as a quantitative design criterion to achieve the optimal-object-oriented designing of superior scatterers.This work can provide an innovative strategy for designing efficient passive daytime radiative cooling materials.展开更多
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
基金The Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project(No.IFKSUOR3-499-1).
文摘AIM:To compare the corneal backward light scattering values in type 2 diabetes mellitus(DM)patients with those of age and sex-matched healthy controls.METHODS:The study included 30 patients(30 eyes)with type 2 DM and 30 control subjects(30 eyes).Duration of diabetes,most recent hemoglobin A1c levels,along with the status of diabetic retinopathy,and existing medical treatment of all subjects were recorded.All subjects underwent a complete ophthalmologic examination.In addition,backward light scattering(densitometry)was measured to assess changes in corneal transparency using tomography(Pentacam HR).RESULTS:The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females.The age was 50.40±7.80y(range:40-68y)of the diabetic group and 49.30±9.50y(rang:40-73y)of control group.The diabetic group demonstrated significantly higher mean densitometry values of the anterior(6-10 mm)zone(P=0.047),the total anterior layer(P=0.036)and the total cornea(P=0.043)than control group.The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration.CONCLUSION:Diabetic group has higher densitometry in anterior corneal(6-10 mm)zone,total anterior cornea,and total cornea and with no correlation with hemoglobin A1c levels and DM duration.
基金financial support from the LASERLAB-EUROPE Access to Research Infrastructure Activity (Application No. 23068)carried out within the framework of EUROfusion Enabling Research Projects AWP21-ENR-01-CEA02 and AWP24-ENR-IFE-02-CEA-02+3 种基金received funding from Euratom Research and Training Programme 2021–2025 under Grant No. 633053supported by the Ministry of Youth and Sports of the Czech Republic [Project No. LM2023068 (PALS RI)]by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDA25030200 and XDA25010100)supported by COST (European Cooperation in Science and Technology) through Action CA21128 PROBONO (PROton BOron Nuclear Fusion: from energy production to medical applicatiOns)
文摘Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of suprathermal hot electrons under interaction conditions envisaged for direct-drive schemes for inertial confinement fusion.Nonetheless,SSRS remains to date one of the least understood parametric instabilities.Here,we report the first angularly and spectrally resolved measurements of scattered light at laser intensities relevant for the shock ignition scheme(I×10^(16)W/cm^(2)),showing significant SSRS growth in the direction perpendicular to the laser polarization.Modification of the focal spot shape and orientation,obtained by using two different random phase plates,and of the density gradient of the plasma,by utilizing exploding foil targets of different thicknesses,clearly reveals a different dependence of backward SRS(BSRS)and SSRS on experimental parameters.While convective BSRS scales with plasma density scale length,as expected by linear theory,the growth of SSRS depends on the spot extension in the direction perpendicular to laser polarization.Our analysis therefore demonstrates that under current experimental conditions,with density scale lengths L_(n)≈60–120μm and spot sizes FWHM≈40–100μm,SSRS is limited by laser beam size rather than by the density scale length of the plasma.
基金V. ACKNOWLEDGMENTS This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology, and the National Natural Science Foundation of China.
文摘Crossed beams scattering study was carried out on the F＋HD→DF＋H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured, with partial rotational state resolution, at eight collision energies in the range of 2.51-5.60 kJ/mol. Experimental results indicated that the product angular distributions are predominantly backward scattered. As the collision energy increases, the backward scattered peak becomes broader gradually. Dependence of product vibration branching ratios on the collision energy was also determined. The experimental results show that the DF products are highly inverted in the vibrational state distribution and the DF （v＇=3） product is the most populated state. Furthermore, the DF （v＇=l） product has also been observed at collision energy above 3.97 kJ/mol.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.11847118)。
文摘The entangled orbital angular momentum(OAM)photons propagating across a weakly turbulent atmosphere are investigated.Here,the paper uses the single-phase screen model based on the Kolmogorov theory of turbulence,and focuses on the influence of the backward scattering on OAM evolution.The results indicate that backward scattering plays an important role in the analysis of OAM entanglement evolution in the turbulent atmosphere.It cannot be negligible especially for higher-order OAM mode.Moreover,when OAM mode is greater than 4,entangled photon pairs composed of higher OAM modes are not more robust in turbulence within the weak scintillation regime.These results will be useful in future investigations of OAM-based optical wave propagation through turbulent atmosphere.
基金supported by the National Natural Science Foundation of China(Grant Nos.52076064,52211530089)the Fundamental Research Funds for the Central Universities(Grant No.HIT.DZJJ.2023095)+1 种基金the National Key Research and Development Program of China(Grant No.2018YFA0702300)Taishan Scholar Foundation of Shandong Province(Grant No.tsqn201812105).
文摘Passive daytime radiative cooling(PDRC)exhibits efficient cooling performance to reduce global fossil energy consumption and has attracted enormous interest.An efficient PDRC technology for achieving daytime subambient cooling is supposed to exhibit ultra-high solar reflectivity and infrared emissivity within atmospheric windows,among which ultra-high solar reflectivity is the principal property.In most PDRC technologies,spherical particles are selected as scatterers to achieve high solar reflectivity because the Mie scattering effect of spherical scatterers can provide a high scattering efficiency.However,the weak backward scattering of spherical scatterers remains a drawback.In this study,several nonspherical scatterers with strong backward scattering are introduced and researched systematically.The numerical analysis results indicate that pyramidal scatterers provide the strongest backward scattering and square/circular scatterers exhibit the highest scattering efficiency.Besides,by considering scattering efficiency and asymmetry factor comprehensively,a dimensionless evaluation parameter is proposed,which can be employed as a quantitative design criterion to achieve the optimal-object-oriented designing of superior scatterers.This work can provide an innovative strategy for designing efficient passive daytime radiative cooling materials.
