The Raman–Nath diffraction in acousto–optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman–Nath diffraction was still considered simply to be ju...The Raman–Nath diffraction in acousto–optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman–Nath diffraction was still considered simply to be just frequency-shifted and to be a plane wave. However, we find that the phase and frequency shifts occur simultaneously and individually in Raman–Nath diffraction. The findings demonstrate that, in addition to the frequency shift, the optical phase of each order of diffracted light is also shifted by the sound wave and fluctuates with the sound wave and is related to the location in the acoustic field from which the diffracted light originates. As a result, the wavefront of each order of diffracted light is modulated to fluctuate spatially and temporally with the sound wave. Obviously, these findings are significant for applications of Raman–Nath diffraction in acousto–optic effect because the optical phase plays an important role in optical coherence technology.展开更多
This paper obtains the exact analytical solution of atomic Raman-Nath diffraction in the coordinate representation and discusses the influence of different initial conditions and detunings on the atomic spatial popula...This paper obtains the exact analytical solution of atomic Raman-Nath diffraction in the coordinate representation and discusses the influence of different initial conditions and detunings on the atomic spatial population distribution. The phase difference between the dipole matrix element and initial atomic population may influence the atomic spatial population distribution after diffraction, which has never been discussed before as far as we know. It offers a method to measure the phase by the spatial population distribution, which is interesting in the study of quantum optics.展开更多
The optimal acousto-optic interaction length in Raman-Nath diffraction is investigated by using deliberately designed apparatus working with pure water. Then the optimum interaction length, the suitable dimensions of ...The optimal acousto-optic interaction length in Raman-Nath diffraction is investigated by using deliberately designed apparatus working with pure water. Then the optimum interaction length, the suitable dimensions of the transducer, and the required index difference dominated by the ultrasonic frequency and power for achieving the ultimate efficiency are analyzed. The portable device analogy to the solid appliance is designed based on the optimization. Taking advantage of the device the highest diffraction efficiency of more than 98% is obtained. The feasibility of using the portable device to act as a Q-switch for ultraviolet and visible lasers is discussed.展开更多
Conventional nonlinear Raman–Nath diffraction(NRND)spots exhibit a straight-line distribution when the pump laser enters the nonlinear dielectric grating at normal incidence or at oblique incidence.Here,we report on ...Conventional nonlinear Raman–Nath diffraction(NRND)spots exhibit a straight-line distribution when the pump laser enters the nonlinear dielectric grating at normal incidence or at oblique incidence.Here,we report on the first observation of the conical NRND phenomenon from a submicron-thick periodically poled lithium niobate thin film(PPLNTF)sample under a near-infrared femtosecond pulse laser excitation at various cone angles.All the multi-order second harmonic generation(SHG)diffraction signals present a novel evolution arc-shaped arrangement feature.展开更多
I. INTRODUCTION The Raman-Nath equation (RNE)was originally derived to describe light diffraction caused by ultrasound. Recently, it is pointed out that RNE is important for one to discuss photon statistical propertie...I. INTRODUCTION The Raman-Nath equation (RNE)was originally derived to describe light diffraction caused by ultrasound. Recently, it is pointed out that RNE is important for one to discuss photon statistical properties of free-electron laser (FEL). In general, RNE takes the following difference-differential展开更多
A novel micro-opto-electro-mechanical system （MOEMS） accelerometer based on Raman-Nath diffraction is presented. It mainly consists of an FPW delay line oscillator and optical strip waveguides. The fun- damental the...A novel micro-opto-electro-mechanical system （MOEMS） accelerometer based on Raman-Nath diffraction is presented. It mainly consists of an FPW delay line oscillator and optical strip waveguides. The fun- damental theories and principles of the device are introduced briefly. A flexural plate-wave delay-line oscillator is designed to work as an acousto-optic （AO） shifter, which has a Klein-Cook parameter of 0.38. Single-mode optical strip waveguides of 2 μm in width and thicknesses of 0.6 μm are designed by using the effective index method for light transmission. The E^y00 mode waveguide polarizers are designed to ensure the consistency of the light polarization in the waveguides. The fabrication process, based on （100） oriented, 450-#m-thick silicon wafers is proposed in detail, and some difficulties in the process are discussed carefully. At last, a series of process tests are undertaken to solve the proposed problems. The results indicate that the proposed design and fabrication process of the device is dependable and realizable.展开更多
The design and simulation of a novel microoptoelectromechanical system （MOEMS） accelerometer based on Raman-Nath diffraction are presented. The device is planned to be fabricated by microelectromechanical system tec...The design and simulation of a novel microoptoelectromechanical system （MOEMS） accelerometer based on Raman-Nath diffraction are presented. The device is planned to be fabricated by microelectromechanical system technology and has a different sensing principle than the other reported MOEMS accelerometers. The fun- damental theories and principles of the device are discussed in detail, a 3D finite element simulation of the flexural plate wave delay line oscillator is provided, and the operation frequency around 40 MHz is calculated. Finally, a lecture experiment is performed to demonstrate the feasibility of the device. This novel accelerometer is proposed to have the advantages of high sensitivity and anti-radiation, and has great potential for various applications.展开更多
When a laser beam is incident on a nonlinear grating with a laterally modulated second-order nonlinear coefficient,nonlinear diffraction of the noncollinear second-harmonic generation(SHG)signal occurs,with Raman–Nat...When a laser beam is incident on a nonlinear grating with a laterally modulated second-order nonlinear coefficient,nonlinear diffraction of the noncollinear second-harmonic generation(SHG)signal occurs,with Raman–Nath nonlinear diffraction(NRND)being a prominent example.As these SHG NRND processes involve coupling between the fundamental-wave pump laser vectorial field and the SHG laser vectorial field through the second-order nonlinearity secondrank tensor of the nonlinear crystal,the nonlinear interaction between light and the nonlinear grating can be manipulated by adjusting the polarization state of the pump laser.In this paper,we derive the relationship between the polarization state of the incident light and the generated nonlinear diffraction signal based on the nonlinear coupled wave equation and experimentally validate the predicted diffraction characteristics.The results show that the optical properties of each order of NRND are highly sensitive to the polarization angle of the incident pump laser beam.展开更多
根据Raman and Nath理论,光在声场中传播可认为是在多层薄光栅中传播,而薄光栅的参数则由光栅平面内的声场分布决定。本文通过圆对称聚焦换能器在焦平面附近的声场分布,得到光束的偏转角与换能器焦点声压的关系。通过测量光束偏转距离...根据Raman and Nath理论,光在声场中传播可认为是在多层薄光栅中传播,而薄光栅的参数则由光栅平面内的声场分布决定。本文通过圆对称聚焦换能器在焦平面附近的声场分布,得到光束的偏转角与换能器焦点声压的关系。通过测量光束偏转距离得到换能器焦点声压。虽然本文的声压与偏转角的关系是基于理想超声聚焦换能器的线性理论,但通过激光检测声压与光纤水听器测量的结果,表明该方法可用于检测较高的焦点声压检测。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61178089)the Science and Technology Program of the Educational Office of Fujian Province of China(Grant Nos.JB12012 and JB13003)
文摘The Raman–Nath diffraction in acousto–optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman–Nath diffraction was still considered simply to be just frequency-shifted and to be a plane wave. However, we find that the phase and frequency shifts occur simultaneously and individually in Raman–Nath diffraction. The findings demonstrate that, in addition to the frequency shift, the optical phase of each order of diffracted light is also shifted by the sound wave and fluctuates with the sound wave and is related to the location in the acoustic field from which the diffracted light originates. As a result, the wavefront of each order of diffracted light is modulated to fluctuate spatially and temporally with the sound wave. Obviously, these findings are significant for applications of Raman–Nath diffraction in acousto–optic effect because the optical phase plays an important role in optical coherence technology.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10575740, 90503010, 60478029 and 10634060） and the National Basic Research Program of China （Grant No 2005CB724508）. The authors would like to thank Professor Wu Ying for stimulating discussion and encouragement.
文摘This paper obtains the exact analytical solution of atomic Raman-Nath diffraction in the coordinate representation and discusses the influence of different initial conditions and detunings on the atomic spatial population distribution. The phase difference between the dipole matrix element and initial atomic population may influence the atomic spatial population distribution after diffraction, which has never been discussed before as far as we know. It offers a method to measure the phase by the spatial population distribution, which is interesting in the study of quantum optics.
文摘The optimal acousto-optic interaction length in Raman-Nath diffraction is investigated by using deliberately designed apparatus working with pure water. Then the optimum interaction length, the suitable dimensions of the transducer, and the required index difference dominated by the ultrasonic frequency and power for achieving the ultimate efficiency are analyzed. The portable device analogy to the solid appliance is designed based on the optimization. Taking advantage of the device the highest diffraction efficiency of more than 98% is obtained. The feasibility of using the portable device to act as a Q-switch for ultraviolet and visible lasers is discussed.
基金Science and Technology Project of Guangdong(2020B010190001)National Natural Science Foundation of China(12434016,11974119)+1 种基金Guangzhou Science and Technology Plan Project(2023A04J1309)National Funded Postdoctoral Researcher Program(GZB20240785)。
文摘Conventional nonlinear Raman–Nath diffraction(NRND)spots exhibit a straight-line distribution when the pump laser enters the nonlinear dielectric grating at normal incidence or at oblique incidence.Here,we report on the first observation of the conical NRND phenomenon from a submicron-thick periodically poled lithium niobate thin film(PPLNTF)sample under a near-infrared femtosecond pulse laser excitation at various cone angles.All the multi-order second harmonic generation(SHG)diffraction signals present a novel evolution arc-shaped arrangement feature.
文摘I. INTRODUCTION The Raman-Nath equation (RNE)was originally derived to describe light diffraction caused by ultrasound. Recently, it is pointed out that RNE is important for one to discuss photon statistical properties of free-electron laser (FEL). In general, RNE takes the following difference-differential
文摘A novel micro-opto-electro-mechanical system （MOEMS） accelerometer based on Raman-Nath diffraction is presented. It mainly consists of an FPW delay line oscillator and optical strip waveguides. The fun- damental theories and principles of the device are introduced briefly. A flexural plate-wave delay-line oscillator is designed to work as an acousto-optic （AO） shifter, which has a Klein-Cook parameter of 0.38. Single-mode optical strip waveguides of 2 μm in width and thicknesses of 0.6 μm are designed by using the effective index method for light transmission. The E^y00 mode waveguide polarizers are designed to ensure the consistency of the light polarization in the waveguides. The fabrication process, based on （100） oriented, 450-#m-thick silicon wafers is proposed in detail, and some difficulties in the process are discussed carefully. At last, a series of process tests are undertaken to solve the proposed problems. The results indicate that the proposed design and fabrication process of the device is dependable and realizable.
文摘The design and simulation of a novel microoptoelectromechanical system （MOEMS） accelerometer based on Raman-Nath diffraction are presented. The device is planned to be fabricated by microelectromechanical system technology and has a different sensing principle than the other reported MOEMS accelerometers. The fun- damental theories and principles of the device are discussed in detail, a 3D finite element simulation of the flexural plate wave delay line oscillator is provided, and the operation frequency around 40 MHz is calculated. Finally, a lecture experiment is performed to demonstrate the feasibility of the device. This novel accelerometer is proposed to have the advantages of high sensitivity and anti-radiation, and has great potential for various applications.
基金Project supported by Science and Technology Project of Guangdong(Grant No.2020B010190001)the National Natural Science Foundation of China(Grant No.12434016)National Funded Postdoctoral Researcher Program(Grant No.GZB20240785)。
文摘When a laser beam is incident on a nonlinear grating with a laterally modulated second-order nonlinear coefficient,nonlinear diffraction of the noncollinear second-harmonic generation(SHG)signal occurs,with Raman–Nath nonlinear diffraction(NRND)being a prominent example.As these SHG NRND processes involve coupling between the fundamental-wave pump laser vectorial field and the SHG laser vectorial field through the second-order nonlinearity secondrank tensor of the nonlinear crystal,the nonlinear interaction between light and the nonlinear grating can be manipulated by adjusting the polarization state of the pump laser.In this paper,we derive the relationship between the polarization state of the incident light and the generated nonlinear diffraction signal based on the nonlinear coupled wave equation and experimentally validate the predicted diffraction characteristics.The results show that the optical properties of each order of NRND are highly sensitive to the polarization angle of the incident pump laser beam.
文摘根据Raman and Nath理论,光在声场中传播可认为是在多层薄光栅中传播,而薄光栅的参数则由光栅平面内的声场分布决定。本文通过圆对称聚焦换能器在焦平面附近的声场分布,得到光束的偏转角与换能器焦点声压的关系。通过测量光束偏转距离得到换能器焦点声压。虽然本文的声压与偏转角的关系是基于理想超声聚焦换能器的线性理论,但通过激光检测声压与光纤水听器测量的结果,表明该方法可用于检测较高的焦点声压检测。
