A novel method to generate a collimated hollow-laser-beam (HLB) by only a single axicon is proposed. With some reasonable assumptions, the radial light intensity distribution is calculated in detail by diffraction int...A novel method to generate a collimated hollow-laser-beam (HLB) by only a single axicon is proposed. With some reasonable assumptions, the radial light intensity distribution is calculated in detail by diffraction integral theory.The result of numerical simulation shows that this method is valid.Compared with other methods of generating HLB,this scheme is extraordinarily simple in principle and can be utilized experimentally to construct a light trap in atomic fountain for convenience.展开更多
Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt regio...Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt region. An experimental method has been developed to measure the integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility. The integral diffraction coefficients of several crystals including polyethylene terephthalate （PET）, thallium acid phthalate （T1AP） and rubidium acid phthalate （RAP） crystals have been measured in the x-ray energy range 2100-5600 eV and compared with the calculations of the ＇Darwin Prins＇ and the ＇Mosaic＇ models. It is shown that the integral diffraction coefficients of these crystals are between the calculations of the ＇Darwin Prins＇ and the ＇Mosaic＇ models, but more close to the ＇Darwin Prins＇ model calculations.展开更多
In this paper, a new kind of light beam called off-axial elliptical cosine-Gaussian beam （ECosGBs） is defined by using the tensor method. An analytical propagation expression for the ECosGBs passing through axially ...In this paper, a new kind of light beam called off-axial elliptical cosine-Gaussian beam （ECosGBs） is defined by using the tensor method. An analytical propagation expression for the ECosGBs passing through axially nonsymmetrical optical systems is derived by using vector integration. The intensity distributions of ECosGBs on the input plane, on the output plane with the equivalent Fresnel number being equal to 0.1 and on the focal plane are respectively illustrated for the propagation properties. The results indicate that an ECosGB is eventually transformed into an elliptical cosh- Gaussian beam. In other words, ECosGBs and cosh-Gaussian beams act in a reciprocal manner after propagation.展开更多
The concept of partially coherent nonparaxial modified Bessel Gauss （MBG） beams is proposed. Based on the generalized Rayleigh-Sommerfeld diffraction integral, the analytical propagation equations of nonparaxial MBG...The concept of partially coherent nonparaxial modified Bessel Gauss （MBG） beams is proposed. Based on the generalized Rayleigh-Sommerfeld diffraction integral, the analytical propagation equations of nonparaxial MBG beams in free space are derived and analysed, and some special cases are discussed. In particular, under the paraxial approximation our results reduce to the corresponding paraxial ones. Numerical calculation examples are given to illustrate the dependence of intensity and spectral degree of coherence on the beam order m, ζ and f parameters, and to compare the difference between the paraxial and nonparaxial results.展开更多
The formalism of generalized diffraction integral for paraxial misaligned optical systems is used to investigate the propagation of the Modified Bessel-Gaussian (MBG) beam through a misaligned thin lens. The propertie...The formalism of generalized diffraction integral for paraxial misaligned optical systems is used to investigate the propagation of the Modified Bessel-Gaussian (MBG) beam through a misaligned thin lens. The properties of the propagation of MBG beam traveling through this misaligned ABCD optical system are discussed. A special case of misaligned circular thin lens is illustrated analytically and numerically. The shape of the MBG beam at the exit of the misaligned optical system is unchanged;however the center of the beam is shifted from the propagation axis in correlated manner with the design parameters of the optical system.展开更多
In this letter, we propose a method for the numerical calculations of the femtosecond laser pulse passed through a subwavelength aperture. The time-dependent laser pulse is decomposed into a series of monochromatic si...In this letter, we propose a method for the numerical calculations of the femtosecond laser pulse passed through a subwavelength aperture. The time-dependent laser pulse is decomposed into a series of monochromatic simple harmonic waves. For the light field of the harmonic wave with a single frequency, the numerical calculation is made based on the solution of the Green's integral equation set of the electromagnetic waves. Such numerical solution is iterated for all the waves with different frequencies, and all the numerical solutions are transformed into the light fields in the time domain by inverse Fourier transform. The light intensity distributions transmitted the subwavelength aperture are calculated and the results show the propagation of the light field is along the direction of the medium interface.展开更多
Ultrasound(US)has emerged as a noninvasive neurostimulation method for motor control in Parkinson’s disease(PD).Previous in vivo US neuromodulation studies for PD were single-target stimulation.However,the motor symp...Ultrasound(US)has emerged as a noninvasive neurostimulation method for motor control in Parkinson’s disease(PD).Previous in vivo US neuromodulation studies for PD were single-target stimulation.However,the motor symptoms of PD are linked with neural circuit dysfunction,and multi-target stimulation is conducted in clinical treatment for PD.Thus,in the present study,we achieved multi-target US stimulation using holographic lens transducer based on the Rayleigh–Sommerfeld diffraction integral and time-reversal methods.We demonstrated that holographic US stimulation of the bilateral dorsal striatum(DS)could improve the motor function in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of PD.The holographic US wave(fundamental frequency:3 MHz,pulse repetition frequency:500 Hz,duty cycle:20%,tone-burst duration:0.4 ms,sonication duration:1 s,interstimulus interval:4 s,spatial-peak temporal-average intensity:180 mw/cm2)was delivered to the bilateral DS 20 min per day for consecutive 10 d after the last injection of MPTP.Immunohistochemical c-Fos staining demonstrated that holographic US significantly increased the c-Fos-positive neurons in the bilateral DS compared with the sham group(P=0.003).Moreover,our results suggested that holographic US stimulation of the bilateral DS ameliorated motor dysfunction(P<0.05)and protected the dopaminergic(DA)neurons(P<0.001).The neuroprotective effect of holographic US was associated with the prevention of axon degeneration and the reinforcement of postsynaptic densities[growth associated protein-43(P<0.001),phosphorylated Akt(P=0.001),β3-tubulin(P<0.001),phosphorylated CRMP2(P=0.037),postsynaptic density(P=0.023)].These data suggested that holographic US-induced acoustic radiation force has the potential to achieve multi-target neuromodulation and could serve as a reliable tool for the treatment of PD.展开更多
The gravitational lensing wave effect generated by a microlensing field embedded in a lens galaxy is an inevitable phenomenon in strong lensed gravitational waves(SLGWs).This effect presents both challenges and opport...The gravitational lensing wave effect generated by a microlensing field embedded in a lens galaxy is an inevitable phenomenon in strong lensed gravitational waves(SLGWs).This effect presents both challenges and opportunities for the detection and appli-cation of SLGWs.However,investigating this wave effect requires computing a complete diffraction integral over each microlens in the field.This is extremely time-consuming due to the large number of microlenses(10^(3)-10^(6)).Therefore,simply adding all the microlenses is impractical.Additionally,the complexity of the time delay surface makes the lens plane resolution a crucial factor in controlling numerical errors.In this paper,we propose a trapezoid approximation-based adaptive hierarchical tree algo-rithm to meet the challenges of calculation speed and precision.We find that this algorithm accelerates the calculation by four orders of magnitude compared to the simple adding method and is one order of magnitude faster than the fixed hierarchical tree algorithm proposed for electromagnetic microlensing.More importantly,our algorithm ensures controllable numerical errors,increasing confidence in the results.Together with our previous work(Sci.China-Phys.Mech.Astron.66,239511,2023),this paper addresses all numerical issues,including integral convergence,precision,and computational time1).Finally,we conducted a population study on the microlensing wave effect of SLGWs using this algorithm and found that the microlensing wave effect cannot be ignored,especially for Type II SLGWs(from saddle position of the time delay surface)due to their intrinsic geometric structures and their typical intersection with a denser microlensing field.Statistically,more than 33%(11%)of SLGWs have a mismatch larger than 1%(3%)compared to the unlensed waveform.Additionally,we found that the mismatch between signal pairs in a doubly imaged GW is generally larger than 10^(−3),and 61%(25%)of signal pairs have a mismatch larger than 1%(3%).Therefore,the microlensing-induced mismatch can reduce the SLGW identification ability using the overlapping method.展开更多
The increase in gravitational wave(GW) events has allowed receiving strong lensing image pairs of GWs. However, the wave effect(diffraction and interference) due to the microlens field contaminates the parameter estim...The increase in gravitational wave(GW) events has allowed receiving strong lensing image pairs of GWs. However, the wave effect(diffraction and interference) due to the microlens field contaminates the parameter estimation of the image pair, which may lead to a misjudgment of strong lensing signals. To quantify the influence of the microlens field, researchers need a large sample of statistical research. Nevertheless, due to the oscillation characteristic, the Fresnel-Kirchhoff diffraction integral’s computational time hinders this aspect’s study. Although many algorithms are available, most cannot be well applied to the case where the microlens field is embedded in galaxy/galaxy clusters. This work proposes a faster and more accurate algorithm for studying the wave optics effect of microlenses embedded in different types of strong lensing images. Additionally, we provide a quantitative estimation criterion for the lens plane boundary for the Fresnel-Kirchhoff diffraction integral. This algorithm can significantly facilitate the study of wave optics, particularly in the case of microlens fields embedded in galaxy/galaxy clusters.展开更多
Integrated diffractive optical neural networks(DONNs)have significant potential for complex machine learning tasks with high speed and ultralow energy consumption.However,the on-chip implementation of a high-performan...Integrated diffractive optical neural networks(DONNs)have significant potential for complex machine learning tasks with high speed and ultralow energy consumption.However,the on-chip implementation of a high-performance optical neural network is limited by input dimensions.In contrast to existing photonic neural networks,a space-time interleaving technology based on arrayed waveguides is designed to realize an on-chip DONN with high-speed,high-dimensional,and all-optical input signal modulation.To demonstrate the performance of the on-chip DONN with high-speed space-time interleaving modulation,an on-chip DONN with a designed footprint of 0.0945 mm~2is proposed to resolve the vowel recognition task,reaching a computation speed of about 1.4×10^(13)operations per second and yielding an accuracy of 98.3%in numerical calculation.In addition,the function of the specially designed arrayed waveguides for realizing parallel signal inputs using space-time conversion has been verified experimentally.This method can realize the on-chip DONN with higher input dimension and lower energy consumption.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 60008002)the Key Oriental Project of Chinese Academy of Sciences (KGCX_2-SW-110)the Shanghai Optical-Tech Special Project (01DJGK015).
文摘A novel method to generate a collimated hollow-laser-beam (HLB) by only a single axicon is proposed. With some reasonable assumptions, the radial light intensity distribution is calculated in detail by diffraction integral theory.The result of numerical simulation shows that this method is valid.Compared with other methods of generating HLB,this scheme is extraordinarily simple in principle and can be utilized experimentally to construct a light trap in atomic fountain for convenience.
基金Project supported by the Foundation of National Key Laboratory of High Temperature and Density Plasma Physics(Grant No.9140C6804020704)the National Natural Science Foundation of China(Grant No.10874156)one of the authors,GanXin-Shi,was also partially supported by the School of Physical Science and Technology in Sichuan University,China
文摘Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt region. An experimental method has been developed to measure the integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility. The integral diffraction coefficients of several crystals including polyethylene terephthalate （PET）, thallium acid phthalate （T1AP） and rubidium acid phthalate （RAP） crystals have been measured in the x-ray energy range 2100-5600 eV and compared with the calculations of the ＇Darwin Prins＇ and the ＇Mosaic＇ models. It is shown that the integral diffraction coefficients of these crystals are between the calculations of the ＇Darwin Prins＇ and the ＇Mosaic＇ models, but more close to the ＇Darwin Prins＇ model calculations.
文摘In this paper, a new kind of light beam called off-axial elliptical cosine-Gaussian beam （ECosGBs） is defined by using the tensor method. An analytical propagation expression for the ECosGBs passing through axially nonsymmetrical optical systems is derived by using vector integration. The intensity distributions of ECosGBs on the input plane, on the output plane with the equivalent Fresnel number being equal to 0.1 and on the focal plane are respectively illustrated for the propagation properties. The results indicate that an ECosGB is eventually transformed into an elliptical cosh- Gaussian beam. In other words, ECosGBs and cosh-Gaussian beams act in a reciprocal manner after propagation.
基金Project supported by the National High Technology Development Program of China （Grant No 823070） and the National Natural Science Foundation of China （Grant No 10574097）.
文摘The concept of partially coherent nonparaxial modified Bessel Gauss （MBG） beams is proposed. Based on the generalized Rayleigh-Sommerfeld diffraction integral, the analytical propagation equations of nonparaxial MBG beams in free space are derived and analysed, and some special cases are discussed. In particular, under the paraxial approximation our results reduce to the corresponding paraxial ones. Numerical calculation examples are given to illustrate the dependence of intensity and spectral degree of coherence on the beam order m, ζ and f parameters, and to compare the difference between the paraxial and nonparaxial results.
文摘The formalism of generalized diffraction integral for paraxial misaligned optical systems is used to investigate the propagation of the Modified Bessel-Gaussian (MBG) beam through a misaligned thin lens. The properties of the propagation of MBG beam traveling through this misaligned ABCD optical system are discussed. A special case of misaligned circular thin lens is illustrated analytically and numerically. The shape of the MBG beam at the exit of the misaligned optical system is unchanged;however the center of the beam is shifted from the propagation axis in correlated manner with the design parameters of the optical system.
文摘In this letter, we propose a method for the numerical calculations of the femtosecond laser pulse passed through a subwavelength aperture. The time-dependent laser pulse is decomposed into a series of monochromatic simple harmonic waves. For the light field of the harmonic wave with a single frequency, the numerical calculation is made based on the solution of the Green's integral equation set of the electromagnetic waves. Such numerical solution is iterated for all the waves with different frequencies, and all the numerical solutions are transformed into the light fields in the time domain by inverse Fourier transform. The light intensity distributions transmitted the subwavelength aperture are calculated and the results show the propagation of the light field is along the direction of the medium interface.
基金supported,in part,by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0930000)the National Natural Science Foundation of China(nos.T2122023,U23A20479,12227809,and 12104478)+1 种基金the Natural Science Foundation of Guangdong Province(no.202381515040008)Shenzhen Basic Science Research(nos.JCYJ20220818101608018,20231123154444001,and 20220812171109001).
文摘Ultrasound(US)has emerged as a noninvasive neurostimulation method for motor control in Parkinson’s disease(PD).Previous in vivo US neuromodulation studies for PD were single-target stimulation.However,the motor symptoms of PD are linked with neural circuit dysfunction,and multi-target stimulation is conducted in clinical treatment for PD.Thus,in the present study,we achieved multi-target US stimulation using holographic lens transducer based on the Rayleigh–Sommerfeld diffraction integral and time-reversal methods.We demonstrated that holographic US stimulation of the bilateral dorsal striatum(DS)could improve the motor function in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of PD.The holographic US wave(fundamental frequency:3 MHz,pulse repetition frequency:500 Hz,duty cycle:20%,tone-burst duration:0.4 ms,sonication duration:1 s,interstimulus interval:4 s,spatial-peak temporal-average intensity:180 mw/cm2)was delivered to the bilateral DS 20 min per day for consecutive 10 d after the last injection of MPTP.Immunohistochemical c-Fos staining demonstrated that holographic US significantly increased the c-Fos-positive neurons in the bilateral DS compared with the sham group(P=0.003).Moreover,our results suggested that holographic US stimulation of the bilateral DS ameliorated motor dysfunction(P<0.05)and protected the dopaminergic(DA)neurons(P<0.001).The neuroprotective effect of holographic US was associated with the prevention of axon degeneration and the reinforcement of postsynaptic densities[growth associated protein-43(P<0.001),phosphorylated Akt(P=0.001),β3-tubulin(P<0.001),phosphorylated CRMP2(P=0.037),postsynaptic density(P=0.023)].These data suggested that holographic US-induced acoustic radiation force has the potential to achieve multi-target neuromodulation and could serve as a reliable tool for the treatment of PD.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1931210,11673065,and 11273061)the science research grants from the China Manned Space Project(Grant No.CMS-CSST-2021-A11)+1 种基金support by the National Natural Science Foundation of China(Grant No.12333001)support by the National Natural Science Foundation of China(Grant No.12133005)。
文摘The gravitational lensing wave effect generated by a microlensing field embedded in a lens galaxy is an inevitable phenomenon in strong lensed gravitational waves(SLGWs).This effect presents both challenges and opportunities for the detection and appli-cation of SLGWs.However,investigating this wave effect requires computing a complete diffraction integral over each microlens in the field.This is extremely time-consuming due to the large number of microlenses(10^(3)-10^(6)).Therefore,simply adding all the microlenses is impractical.Additionally,the complexity of the time delay surface makes the lens plane resolution a crucial factor in controlling numerical errors.In this paper,we propose a trapezoid approximation-based adaptive hierarchical tree algo-rithm to meet the challenges of calculation speed and precision.We find that this algorithm accelerates the calculation by four orders of magnitude compared to the simple adding method and is one order of magnitude faster than the fixed hierarchical tree algorithm proposed for electromagnetic microlensing.More importantly,our algorithm ensures controllable numerical errors,increasing confidence in the results.Together with our previous work(Sci.China-Phys.Mech.Astron.66,239511,2023),this paper addresses all numerical issues,including integral convergence,precision,and computational time1).Finally,we conducted a population study on the microlensing wave effect of SLGWs using this algorithm and found that the microlensing wave effect cannot be ignored,especially for Type II SLGWs(from saddle position of the time delay surface)due to their intrinsic geometric structures and their typical intersection with a denser microlensing field.Statistically,more than 33%(11%)of SLGWs have a mismatch larger than 1%(3%)compared to the unlensed waveform.Additionally,we found that the mismatch between signal pairs in a doubly imaged GW is generally larger than 10^(−3),and 61%(25%)of signal pairs have a mismatch larger than 1%(3%).Therefore,the microlensing-induced mismatch can reduce the SLGW identification ability using the overlapping method.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1931210,11673065,and 11273061)the Science Research Grants from the China Manned Space Project(Grant No.CMSCSST-2021-A11)+5 种基金the Sugon Advanced Computing Service Platform for Computing Supportthe Cosmology Simulation Database(CSD)in the National Basic Science Data Center(NBSDC)its funds the NBSDC-DB-10(Grant No.2020000088)supported by the National Key R&D Program of China(Grant No.2021YFC2203100)the National Natural Science Foundation of China(Grant Nos.11903030,and 11903033)the Fundamental Research Funds for the Central Universities(Grant Nos.WK2030000036,and WK3440000004)。
文摘The increase in gravitational wave(GW) events has allowed receiving strong lensing image pairs of GWs. However, the wave effect(diffraction and interference) due to the microlens field contaminates the parameter estimation of the image pair, which may lead to a misjudgment of strong lensing signals. To quantify the influence of the microlens field, researchers need a large sample of statistical research. Nevertheless, due to the oscillation characteristic, the Fresnel-Kirchhoff diffraction integral’s computational time hinders this aspect’s study. Although many algorithms are available, most cannot be well applied to the case where the microlens field is embedded in galaxy/galaxy clusters. This work proposes a faster and more accurate algorithm for studying the wave optics effect of microlenses embedded in different types of strong lensing images. Additionally, we provide a quantitative estimation criterion for the lens plane boundary for the Fresnel-Kirchhoff diffraction integral. This algorithm can significantly facilitate the study of wave optics, particularly in the case of microlens fields embedded in galaxy/galaxy clusters.
基金supported by the National Natural Science Foundation of China(NSFC)(No.62135009)the Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z221100005322010)。
文摘Integrated diffractive optical neural networks(DONNs)have significant potential for complex machine learning tasks with high speed and ultralow energy consumption.However,the on-chip implementation of a high-performance optical neural network is limited by input dimensions.In contrast to existing photonic neural networks,a space-time interleaving technology based on arrayed waveguides is designed to realize an on-chip DONN with high-speed,high-dimensional,and all-optical input signal modulation.To demonstrate the performance of the on-chip DONN with high-speed space-time interleaving modulation,an on-chip DONN with a designed footprint of 0.0945 mm~2is proposed to resolve the vowel recognition task,reaching a computation speed of about 1.4×10^(13)operations per second and yielding an accuracy of 98.3%in numerical calculation.In addition,the function of the specially designed arrayed waveguides for realizing parallel signal inputs using space-time conversion has been verified experimentally.This method can realize the on-chip DONN with higher input dimension and lower energy consumption.
