In order to achieve high-accuracy measurement of radius of curvature of optical sphere, ultra-high accuracy radius of curvature testing device is developed by dual-frequency laser interferometer and Fizeau interferome...In order to achieve high-accuracy measurement of radius of curvature of optical sphere, ultra-high accuracy radius of curvature testing device is developed by dual-frequency laser interferometer and Fizeau interferometer based on cat’s eye and confocal method. Through analyzing the error source models of radius of curvature testing, optical configuration of the testing device has been optimized. Precise environment control and real-time monitoring system is also established to reduce the errors caused by environment. Through the above processes, the radius of curvature measurement relative accuracy is better than 2 ppm. One optical sphere, R88.5 mm, test aperture 59 mm, has been tested. Testing result is 88499.465 ± 0.176 μm, meeting the design requirement. The method has high accuracy and practical advantages.展开更多
A new multi-channel far infrared (FIR) laser interferometer was built up and ap- plied to HL-2A. The unique feature of real-time heterodyne interferometer is the combination of high power radiation source (300 mW)...A new multi-channel far infrared (FIR) laser interferometer was built up and ap- plied to HL-2A. The unique feature of real-time heterodyne interferometer is the combination of high power radiation source (300 mW), lower noise room temperature detector (noise tempera- ture below 6000 K) with good spatial resolution of 7 cm. Various parameters are optimized for maximum laser output power. Zero crossings of the signals are counted with field programmable gate array (FPGA) digital circuitry yielding the resolution of 1/1000 fringe. The newly measured results including density fluctuation are also presented.展开更多
The optical feedback characteristics in a Zeeman-birefringence dual-frequency laser are studied during the laser cavity tuning in three different kinds of optical feedback conditions: (i) only //-light is fed back;...The optical feedback characteristics in a Zeeman-birefringence dual-frequency laser are studied during the laser cavity tuning in three different kinds of optical feedback conditions: (i) only //-light is fed back; (ii) only ⊥-light is fed back; (iii) both lights are fed back. A compact displacement sensor is designed using the experimental result that there is a nearly 90 degrees phase delay between the two lights' cosine optical feedback signals when both lights are fed back into the laser cavity. The priority order that the two lights' intensity curves appear can be used for direction discrimination. The resolution of the displacement sensor is at least 79 rim, and the sensor can discriminate the target's moving direction easily.展开更多
A single-channel far-infrared (FIR) laser interferometer was developed to measure the line averaged electron density on the EAST tokamak. The structure of the single-channel FIR laser interferometer is described in ...A single-channel far-infrared (FIR) laser interferometer was developed to measure the line averaged electron density on the EAST tokamak. The structure of the single-channel FIR laser interferometer is described in detail. The evolution of density sawtooth oscillation was measured by means the FIR laser interferometer, and was identified by electron cyclotron emission (ECE) signals and soft X-ray intensity. The discharges with and without sawtooth were compared with each other in the Hugill diagram.展开更多
The accuracy and repeatability of the laser interferometer measurement system (LIMS) are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new ...The accuracy and repeatability of the laser interferometer measurement system (LIMS) are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new method to calibrate mirror map on ultraprecise movement stage (UPMS) with nanopositioning and to make a real-time compensation for the mirror surface error by using mirror map data tables with the software algorithm. Based on the mirror map test model, the factors affecting mirror map are analyzed through geometric method on the UPMS with six digrees of freedom. Dam processing methods including spline interpolation and spline offsets are used to process the raw sampling data to build mirror map tables. The linear interpolation as compensation method to make a real-time correction on the stage mirror unflatness is adopted and the correction formulas are illuminated. In this way, the measurement accuracy of the system is obviously improved from 40 nm to 5 nm.展开更多
Accuracy is one of the most important key indices to evaluate multi-axis systems’ (MAS’s) characteristics and performances. The accuracy of MAS’s such as machine tools, measuring machines and robots is adversely af...Accuracy is one of the most important key indices to evaluate multi-axis systems’ (MAS’s) characteristics and performances. The accuracy of MAS’s such as machine tools, measuring machines and robots is adversely affected by various error sources, including geometric imperfections, thermal deformations, load effects, and dynamic disturbances. The increasing demand for higher dimensional accuracy in various industrial applications has created the need to develop cost-effective methods for enhancing the overall performance of these mechanisms. Improving the accuracy of a MAS by upgrading the physical structure would lead to an exponential increase in manufacturing costs without totally eliminating geometrical deviations and thermal deformations of MAS components. Hence, the idea of reducing MAS’s error by a software-based alternative approach to provide real-time prediction and correction of geometric and thermally induced errors is considered a strategic step toward achieving the full potential of the MAS. This paper presents a structured approach designed to improve the accuracy of Cartesian MAS’s through software error compensation. Four steps are required to develop and implement this approach: (i) measurement of error components using a multidimensional laser interferometer system, (ii) tridimensional volumetric error mapping using rigid body kinematics, (iii) volumetric error prediction via an artificial neural network model, and finally (iv) implementation of the on-line error compensation. An illustrative example using a bridge type coordinate measuring machine is presented.展开更多
The method and experimental results of measuring a small vibrating displacement by laser interferometer are introduced in this paper. The dynamic response of a new kind of tiny piezoelectric driver is detected. Result...The method and experimental results of measuring a small vibrating displacement by laser interferometer are introduced in this paper. The dynamic response of a new kind of tiny piezoelectric driver is detected. Results show that this kind of PZN-PZT tiny driver not only has high voltage-displacement sensitivity, but also its frequency response approaches to 1 kHz.Therefore this kind of piezoelectric driver can be used widely in many fields.展开更多
A method is proposed to solve the problem of direction discrimination for laser feedback interferometers. By vibrating the feedback mirror with a small-amplitude and high-frequency sine wave, laser intensity is modula...A method is proposed to solve the problem of direction discrimination for laser feedback interferometers. By vibrating the feedback mirror with a small-amplitude and high-frequency sine wave, laser intensity is modulated accordingly. The modulation amplitude can be extracted using a phase sensitive detector (PSD). When the feedback mirror moves, the PSD output shows a quasi-sine waveform similar to a laser intensity interference fringe but with a phase difference of approximately ±π/2. If the movement direction of the feedback mirror changes, the phase difference sign reverses. Therefore, the laser feedback interferometer offers a potential application in displacement measurement with a resolution of 1/8 wavelength and in-time direction discrimination. Without using optical components such as polarization beam splitters and wave plates, the interferometer is very simple, easy to align, and less costly.展开更多
A multichannel methanoic acid (HCOOH, λ=432.5 μm) laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide (HCN, λ=337 μm) laser interferometer in the HL-2A tokamak....A multichannel methanoic acid (HCOOH, λ=432.5 μm) laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide (HCN, λ=337 μm) laser interferometer in the HL-2A tokamak. A conventional Michelson-type interometer is used for the electron density measurement, and a Dodel-Kunz-type polarimeter is used for the Faraday rotation effect measurement, respectively. Each HCOOH laser can produce a linearly polarized radiation at a power lever of -30 mW, and a power stability 〈10% in 50 rain. A beam waist (diameter d0 ≈12.0 mm, about 200 mm away from the outlet) is finally determined through a chopping modulation technique. The latest optical layout of the interferometer/polarimeter has been finished, and the hardware data processing system based on the fast Fourier transform phase- comparator technique is being explored. In order to demonstrate the feasibility of the diagnostic scheme, two associated bench simulation experiments were carried out in the laboratory, in which the plasma was simulated by a piece of polytetrafluoroethene plate, and the Faraday rotation effect was simulated by a rotating half-wave plate. Simulation results agreed well with the initial experimental conditions. At present, the HCOOH laser interferometer/polarimeter system is being assembled on HL-2A, and is planned to be applied in the 2014-2015 experimental campaign.展开更多
We consider an extremely intense laser,enclosed by an atom interferometer.The gravitational potential generated from the high-intensity laser is solved from the Einstein field equation under the Newtonian limit.We com...We consider an extremely intense laser,enclosed by an atom interferometer.The gravitational potential generated from the high-intensity laser is solved from the Einstein field equation under the Newtonian limit.We compute the strength of the gravitational force and study the feasibility of measuring the force by the atom interferometer.The intense laser field from the laser pulse can induce a phase change in the interferometer with Bose-Einstein condensates.We push up the sensitivity limit of the interferometer with Bose-Einstein condensates by spin-squeezing effect and determine the sensitivity gap for measuring the gravitational effect from intense laser by atom interferometer.展开更多
For the development of the aviation industry, machine tools are becoming large and travel long distances, making optical alignment setup difficult. An auto-tracking laser interferometer (ATLI) is proposed and research...For the development of the aviation industry, machine tools are becoming large and travel long distances, making optical alignment setup difficult. An auto-tracking laser interferometer (ATLI) is proposed and researched in this paper for the squareness error measurement of machine tools or coordinate-measuring machines (CMMs). The procedure involves measurement of only one line of an axis, and the measurement results provide us information about not only the positioning errors but also the squareness errors. This specially designed interferometer instrument can be useful in checking industrial machine tools in a short time.展开更多
The optical injection locking of semiconductor lasers to dual-frequency lasers is studied by numerical simulations.The beat-note signals can be effectively transformed to optical frequency combs due to the effective f...The optical injection locking of semiconductor lasers to dual-frequency lasers is studied by numerical simulations.The beat-note signals can be effectively transformed to optical frequency combs due to the effective four wave-mixing in the active semiconductor gain medium. The low-noise Gaussian-like pulse can be obtained by locking the relaxation oscillation and compensating the gain asymmetry. The simulations suggest that pulse trains of width below 30 ps and repetition rate in GHz frequency can be generated simply by the optical injection locking of semiconductor lasers. Since the optical injection locking can broaden the spectrum and amplify the optical power simultaneously, it can be a good initial stage for generating optical frequency combs from dual-frequency lasers by multi-stage of spectral broadening in nonlinear waveguides.展开更多
In National Astronomical Observatory, Japan, Mitaka, a group of scientists has been constructing a laser interferometer with two Fabry Perot cavities 300m long, one in North South and one in East West directions. The ...In National Astronomical Observatory, Japan, Mitaka, a group of scientists has been constructing a laser interferometer with two Fabry Perot cavities 300m long, one in North South and one in East West directions. The interferomer is to detect any gravitational wave near 400Hz frequency and stronger than 10 -20 by autumn, 1998 all the instruments have been installed in the underground facilities and it will be operated for more than 30 days in April, 1999. Then a recycling device will be installed to increase the sensitivity by factor of 10. In this paper this system as well as other systems such as LIGOs in UAS and VIRGO in Europe will be reviewed.展开更多
We introduce a programmable eight-port interferometer with the recently proposed error-tolerant architecture capable of performing a broad class of transformations.The interferometer has been fabricated with femtoseco...We introduce a programmable eight-port interferometer with the recently proposed error-tolerant architecture capable of performing a broad class of transformations.The interferometer has been fabricated with femtosecond laser writing,and it is the largest programmable interferometer of this kind to date.We have demonstrated its advantageous error tolerance by showing an operation in a broad wavelength range from 920 to 980 nm,which is particularly relevant for quantum photonics due to efficient photon sources existing in this wavelength range.Our work highlights the importance of developing novel architectures of programmable photonics for information processing.展开更多
Precision measurement tools are compulsory to reduce measurement errors or machining errors in the processes of calibration and manufacturing.The laser interferometer is one of the most important measurement tools inv...Precision measurement tools are compulsory to reduce measurement errors or machining errors in the processes of calibration and manufacturing.The laser interferometer is one of the most important measurement tools invented in the 20th century.Today,it is commonly used in ultraprecision machining and manufacturing,ultraprecision positioning control,and many noncontact optical sensing technologies.So far,the state-of-the-art laser interferometers are the ground-based gravitational-wave detectors,e.g.the Laser Interferometer Gravitational-wave Observatory(LIGO).The LIGO has reached the measurement quantum limit,and some quantum technologies with squeezed light are currently being tested in order to further decompress the noise level.In this paper,we focus on the laser interferometry developed for space-based gravitational-wave detection.The basic working principle and the current status of the key technologies of intersatellite laser interferometry are introduced and discussed in detail.The launch and operation of these large-scale,gravitational-wave detectors based on space-based laser interferometry is proposed for the 2030s.展开更多
An air-spark switch plasma was diagnosed by the Mach–Zehnder laser interferometer with ultra-high spatial and temporal resolution. The interferograms containing plasma phase shift information at different time were o...An air-spark switch plasma was diagnosed by the Mach–Zehnder laser interferometer with ultra-high spatial and temporal resolution. The interferograms containing plasma phase shift information at different time were obtained. The phase shift distributions of the plasma were extracted by numerically processing the interferograms. The three-dimensional(3 D) electron density distributions of the air-spark switch plasma were then obtained. The working process of the air-spark switch was described by analyzing the temporal and spatial evolution of the plasma electron density.展开更多
文摘In order to achieve high-accuracy measurement of radius of curvature of optical sphere, ultra-high accuracy radius of curvature testing device is developed by dual-frequency laser interferometer and Fizeau interferometer based on cat’s eye and confocal method. Through analyzing the error source models of radius of curvature testing, optical configuration of the testing device has been optimized. Precise environment control and real-time monitoring system is also established to reduce the errors caused by environment. Through the above processes, the radius of curvature measurement relative accuracy is better than 2 ppm. One optical sphere, R88.5 mm, test aperture 59 mm, has been tested. Testing result is 88499.465 ± 0.176 μm, meeting the design requirement. The method has high accuracy and practical advantages.
基金National Natural Science Foundation of China (Nos.10575030,10675043)the JSPS-CAS Core University Program in the field of Plasma and Nuclear Fusion
文摘A new multi-channel far infrared (FIR) laser interferometer was built up and ap- plied to HL-2A. The unique feature of real-time heterodyne interferometer is the combination of high power radiation source (300 mW), lower noise room temperature detector (noise tempera- ture below 6000 K) with good spatial resolution of 7 cm. Various parameters are optimized for maximum laser output power. Zero crossings of the signals are counted with field programmable gate array (FPGA) digital circuitry yielding the resolution of 1/1000 fringe. The newly measured results including density fluctuation are also presented.
基金Project supported by the National Natural Science Foundation of China (Grant No 60437030).
文摘The optical feedback characteristics in a Zeeman-birefringence dual-frequency laser are studied during the laser cavity tuning in three different kinds of optical feedback conditions: (i) only //-light is fed back; (ii) only ⊥-light is fed back; (iii) both lights are fed back. A compact displacement sensor is designed using the experimental result that there is a nearly 90 degrees phase delay between the two lights' cosine optical feedback signals when both lights are fed back into the laser cavity. The priority order that the two lights' intensity curves appear can be used for direction discrimination. The resolution of the displacement sensor is at least 79 rim, and the sensor can discriminate the target's moving direction easily.
基金National Natural Science Foundation of China(Nos.10475078,10675127,10675126,10675124,10605028)
文摘A single-channel far-infrared (FIR) laser interferometer was developed to measure the line averaged electron density on the EAST tokamak. The structure of the single-channel FIR laser interferometer is described in detail. The evolution of density sawtooth oscillation was measured by means the FIR laser interferometer, and was identified by electron cyclotron emission (ECE) signals and soft X-ray intensity. The discharges with and without sawtooth were compared with each other in the Hugill diagram.
文摘The accuracy and repeatability of the laser interferometer measurement system (LIMS) are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new method to calibrate mirror map on ultraprecise movement stage (UPMS) with nanopositioning and to make a real-time compensation for the mirror surface error by using mirror map data tables with the software algorithm. Based on the mirror map test model, the factors affecting mirror map are analyzed through geometric method on the UPMS with six digrees of freedom. Dam processing methods including spline interpolation and spline offsets are used to process the raw sampling data to build mirror map tables. The linear interpolation as compensation method to make a real-time correction on the stage mirror unflatness is adopted and the correction formulas are illuminated. In this way, the measurement accuracy of the system is obviously improved from 40 nm to 5 nm.
文摘Accuracy is one of the most important key indices to evaluate multi-axis systems’ (MAS’s) characteristics and performances. The accuracy of MAS’s such as machine tools, measuring machines and robots is adversely affected by various error sources, including geometric imperfections, thermal deformations, load effects, and dynamic disturbances. The increasing demand for higher dimensional accuracy in various industrial applications has created the need to develop cost-effective methods for enhancing the overall performance of these mechanisms. Improving the accuracy of a MAS by upgrading the physical structure would lead to an exponential increase in manufacturing costs without totally eliminating geometrical deviations and thermal deformations of MAS components. Hence, the idea of reducing MAS’s error by a software-based alternative approach to provide real-time prediction and correction of geometric and thermally induced errors is considered a strategic step toward achieving the full potential of the MAS. This paper presents a structured approach designed to improve the accuracy of Cartesian MAS’s through software error compensation. Four steps are required to develop and implement this approach: (i) measurement of error components using a multidimensional laser interferometer system, (ii) tridimensional volumetric error mapping using rigid body kinematics, (iii) volumetric error prediction via an artificial neural network model, and finally (iv) implementation of the on-line error compensation. An illustrative example using a bridge type coordinate measuring machine is presented.
文摘The method and experimental results of measuring a small vibrating displacement by laser interferometer are introduced in this paper. The dynamic response of a new kind of tiny piezoelectric driver is detected. Results show that this kind of PZN-PZT tiny driver not only has high voltage-displacement sensitivity, but also its frequency response approaches to 1 kHz.Therefore this kind of piezoelectric driver can be used widely in many fields.
文摘A method is proposed to solve the problem of direction discrimination for laser feedback interferometers. By vibrating the feedback mirror with a small-amplitude and high-frequency sine wave, laser intensity is modulated accordingly. The modulation amplitude can be extracted using a phase sensitive detector (PSD). When the feedback mirror moves, the PSD output shows a quasi-sine waveform similar to a laser intensity interference fringe but with a phase difference of approximately ±π/2. If the movement direction of the feedback mirror changes, the phase difference sign reverses. Therefore, the laser feedback interferometer offers a potential application in displacement measurement with a resolution of 1/8 wavelength and in-time direction discrimination. Without using optical components such as polarization beam splitters and wave plates, the interferometer is very simple, easy to align, and less costly.
基金supported by the National Magnetic Confinement Fusion Science Programs of China(Nos.2010GB101002 and 2014GB109001)National Natural Science Foundation of China(Nos.11075048 and 11275059)
文摘A multichannel methanoic acid (HCOOH, λ=432.5 μm) laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide (HCN, λ=337 μm) laser interferometer in the HL-2A tokamak. A conventional Michelson-type interometer is used for the electron density measurement, and a Dodel-Kunz-type polarimeter is used for the Faraday rotation effect measurement, respectively. Each HCOOH laser can produce a linearly polarized radiation at a power lever of -30 mW, and a power stability 〈10% in 50 rain. A beam waist (diameter d0 ≈12.0 mm, about 200 mm away from the outlet) is finally determined through a chopping modulation technique. The latest optical layout of the interferometer/polarimeter has been finished, and the hardware data processing system based on the fast Fourier transform phase- comparator technique is being explored. In order to demonstrate the feasibility of the diagnostic scheme, two associated bench simulation experiments were carried out in the laboratory, in which the plasma was simulated by a piece of polytetrafluoroethene plate, and the Faraday rotation effect was simulated by a rotating half-wave plate. Simulation results agreed well with the initial experimental conditions. At present, the HCOOH laser interferometer/polarimeter system is being assembled on HL-2A, and is planned to be applied in the 2014-2015 experimental campaign.
基金the support by Ministry of Higher Education Malaysia under Long-Term Research Grant Scheme,LRGS/1/2020/UM/01/5/1。
文摘We consider an extremely intense laser,enclosed by an atom interferometer.The gravitational potential generated from the high-intensity laser is solved from the Einstein field equation under the Newtonian limit.We compute the strength of the gravitational force and study the feasibility of measuring the force by the atom interferometer.The intense laser field from the laser pulse can induce a phase change in the interferometer with Bose-Einstein condensates.We push up the sensitivity limit of the interferometer with Bose-Einstein condensates by spin-squeezing effect and determine the sensitivity gap for measuring the gravitational effect from intense laser by atom interferometer.
文摘For the development of the aviation industry, machine tools are becoming large and travel long distances, making optical alignment setup difficult. An auto-tracking laser interferometer (ATLI) is proposed and researched in this paper for the squareness error measurement of machine tools or coordinate-measuring machines (CMMs). The procedure involves measurement of only one line of an axis, and the measurement results provide us information about not only the positioning errors but also the squareness errors. This specially designed interferometer instrument can be useful in checking industrial machine tools in a short time.
基金Project supported by the National Natural Science Foundation of China(Grant No.62005215)。
文摘The optical injection locking of semiconductor lasers to dual-frequency lasers is studied by numerical simulations.The beat-note signals can be effectively transformed to optical frequency combs due to the effective four wave-mixing in the active semiconductor gain medium. The low-noise Gaussian-like pulse can be obtained by locking the relaxation oscillation and compensating the gain asymmetry. The simulations suggest that pulse trains of width below 30 ps and repetition rate in GHz frequency can be generated simply by the optical injection locking of semiconductor lasers. Since the optical injection locking can broaden the spectrum and amplify the optical power simultaneously, it can be a good initial stage for generating optical frequency combs from dual-frequency lasers by multi-stage of spectral broadening in nonlinear waveguides.
文摘In National Astronomical Observatory, Japan, Mitaka, a group of scientists has been constructing a laser interferometer with two Fabry Perot cavities 300m long, one in North South and one in East West directions. The interferomer is to detect any gravitational wave near 400Hz frequency and stronger than 10 -20 by autumn, 1998 all the instruments have been installed in the underground facilities and it will be operated for more than 30 days in April, 1999. Then a recycling device will be installed to increase the sensitivity by factor of 10. In this paper this system as well as other systems such as LIGOs in UAS and VIRGO in Europe will be reviewed.
基金State Atomic Energy Corporation ROSATOM(868-1.3-15/15-2021,Roadmap for Quantum computing)Russian Science Foundation(22-12-00353)。
文摘We introduce a programmable eight-port interferometer with the recently proposed error-tolerant architecture capable of performing a broad class of transformations.The interferometer has been fabricated with femtosecond laser writing,and it is the largest programmable interferometer of this kind to date.We have demonstrated its advantageous error tolerance by showing an operation in a broad wavelength range from 920 to 980 nm,which is particularly relevant for quantum photonics due to efficient photon sources existing in this wavelength range.Our work highlights the importance of developing novel architectures of programmable photonics for information processing.
基金the National Natural Science Foundation of China(Grant Nos.11655001,11654004,91836104).
文摘Precision measurement tools are compulsory to reduce measurement errors or machining errors in the processes of calibration and manufacturing.The laser interferometer is one of the most important measurement tools invented in the 20th century.Today,it is commonly used in ultraprecision machining and manufacturing,ultraprecision positioning control,and many noncontact optical sensing technologies.So far,the state-of-the-art laser interferometers are the ground-based gravitational-wave detectors,e.g.the Laser Interferometer Gravitational-wave Observatory(LIGO).The LIGO has reached the measurement quantum limit,and some quantum technologies with squeezed light are currently being tested in order to further decompress the noise level.In this paper,we focus on the laser interferometry developed for space-based gravitational-wave detection.The basic working principle and the current status of the key technologies of intersatellite laser interferometry are introduced and discussed in detail.The launch and operation of these large-scale,gravitational-wave detectors based on space-based laser interferometry is proposed for the 2030s.
文摘An air-spark switch plasma was diagnosed by the Mach–Zehnder laser interferometer with ultra-high spatial and temporal resolution. The interferograms containing plasma phase shift information at different time were obtained. The phase shift distributions of the plasma were extracted by numerically processing the interferograms. The three-dimensional(3 D) electron density distributions of the air-spark switch plasma were then obtained. The working process of the air-spark switch was described by analyzing the temporal and spatial evolution of the plasma electron density.