Contents
1999
Volume: 19 Issue 12
23 Article(s)
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Atmospheric Optics and Oceanic Optics
Analysis of Compensation Effectiveness for Adaptive Optical System Used as Low-Order Modes Correction
[in Chinese], [in Chinese], and [in Chinese]
Phase structure function, residual phase structure function and long-exposure optical transfer function (OTF) of an adaptive optical system used as low-order modes correction are deduced by introducing the generalized phase spatial spectrum when low-order modes are corrected. Numerical results of long-exposure OTF, StrPhase structure function, residual phase structure function and long-exposure optical transfer function (OTF) of an adaptive optical system used as low-order modes correction are deduced by introducing the generalized phase spatial spectrum when low-order modes are corrected. Numerical results of long-exposure OTF, Strehl ratio and FWHM for different ρ0, which shows the state of atmospheric turbulence, and different β, which is the power-law exponent of phase power spectrum, are presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1615 (1999)
Optimization of Temporal Response Frequences for Adaptive Optics Telescope
[in Chinese], [in Chinese], and [in Chinese]
The relationship between residual wavefront phase error and frequency response in an adaptive optical telescope is analyzed. Mathematical formulations are derived for temporal response error and wavefront measurement error respectively. The results show that one part of residual wavefront phase error changes with cut-oThe relationship between residual wavefront phase error and frequency response in an adaptive optical telescope is analyzed. Mathematical formulations are derived for temporal response error and wavefront measurement error respectively. The results show that one part of residual wavefront phase error changes with cut-off frequency proportionally and another part inversely, so it becomes possible to find an optimal frequency which makes the systematic residual wavefront error minimal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1625 (1999)
Analysis of Spatial and Temporal Structure of Optical Turbulence in the Convective Turbulent Tank
[in Chinese], [in Chinese], and [in Chinese]
The spatial and temporal correlations of refraction index and irradiance scintillation in the convective turbulent tank for adaptive optics wavefront compensitive experiments are analyzed. The correlation functions are developed when the average velocity U0～0 or U0=0. The diffusion due to turbulent evolution increased The spatial and temporal correlations of refraction index and irradiance scintillation in the convective turbulent tank for adaptive optics wavefront compensitive experiments are analyzed. The correlation functions are developed when the average velocity U0～0 or U0=0. The diffusion due to turbulent evolution increased is discussed in detail when velocity fluctuations V′ enlerging. The numerical calculation and experimental results show that temporal correlation decreases more rapidly and inner scale of frequency spectrum gets smaller due to turbulent evolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1630 (1999)
Wavelet Spectrum Analysis of Laser Scintillation in a Turbulent Atmosphere
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Since scaling exponents fitted from many fast Fourier transformation (FFT) power spectra of the log-intensity of laser beam in the turbulent atmosphere go beyond the theoretical bound, the discrete wavelet transformation (DWT) power spectrum was introduced. The superiority of DWT over FFT is verified through comparisonSince scaling exponents fitted from many fast Fourier transformation (FFT) power spectra of the log-intensity of laser beam in the turbulent atmosphere go beyond the theoretical bound, the discrete wavelet transformation (DWT) power spectrum was introduced. The superiority of DWT over FFT is verified through comparison of the scaling exponents fitted from the FFT and DWT power spectra of 1/f noises. The scaling exponents in the scaling region of the DWT power spectrum of laser scintillation vary smoothly in a whole day (except sunrise and sunset time) and lie in the bound. It is suggested that DWT instead of FFT should be used in the spectrum analysis of laser scintillation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1634 (1999)
Fiber Optics and Optical Communications
Spectrum-Transmission Function of Optic-Fiber Ring
[in Chinese], and [in Chinese]
The spectrum-transmission function (STF) of optic-fiber ring is obtained with the theory of partially coherent light. The effects of the optical length, the output couple coefficient, and the loss on the STF of optic fiber ring are analyzed.The spectrum-transmission function (STF) of optic-fiber ring is obtained with the theory of partially coherent light. The effects of the optical length, the output couple coefficient, and the loss on the STF of optic fiber ring are analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1639 (1999)
Fourier Optics and Signal Processing
Quantitative Analysis of Aliasing Effects in Opto-Electric Imaging Systems
[in Chinese], and [in Chinese]
In opto-electric imaging systems, aliasing will occur when sampling a scene containing spatial frequencies exceeding half of the sampling frequency. By the use of vector analysis method, a quantitative aliasing expression for an sinusoidal elementary image is given. Moire effect as an aliasing phenomenon of periodic obIn opto-electric imaging systems, aliasing will occur when sampling a scene containing spatial frequencies exceeding half of the sampling frequency. By the use of vector analysis method, a quantitative aliasing expression for an sinusoidal elementary image is given. Moire effect as an aliasing phenomenon of periodic objects and aliasing contents as signal dependent noise of non-periodic objects are analysed. Computer simulations are presented for both cases..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1649 (1999)
An Algorithm To Raise the Locating Precision of Laser Spot Center Based on Hough Transform
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The precise location of the laser spot center is an important step to raise the measurement resolution in large 3-D surface profile measuring system of laser scanning. While measured distance is large, laser spot intensity distributes non-uniformly so that the deviation between the geometric center and the intensive ceThe precise location of the laser spot center is an important step to raise the measurement resolution in large 3-D surface profile measuring system of laser scanning. While measured distance is large, laser spot intensity distributes non-uniformly so that the deviation between the geometric center and the intensive center of the spot emerges because of the influence of various factors. The conventional methods of locating center of spot is unsuitable to the condition. According to the feature that the better part of circle spot can be obtained by the image of spot, a new method for locating the center of spot based on Hough transform (HT) is presented. The experimental results show that the method can effectively increase the measuring precision of large scale 3-D surface profile..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1655 (1999)
Lasers and Laser Optics
All-Fiber Tunable Q-Switched Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Active-Q-switching and self-Q-switching have been observed in a tunable fiber ring laser. The tuning width of 5.7 nm, active-Q-switched pulse with a peak power of 2.6 W and a average power of 1 mW have been successfully demonstrated. Some explanation for the reasons of self-Q-switching has been given.Active-Q-switching and self-Q-switching have been observed in a tunable fiber ring laser. The tuning width of 5.7 nm, active-Q-switched pulse with a peak power of 2.6 W and a average power of 1 mW have been successfully demonstrated. Some explanation for the reasons of self-Q-switching has been given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1645 (1999)
Materials
Upconversion Fluorescence Spectroscopy in AlF3-Based Fluoride Glass with High Erbium Dopant Level Under 800 nm Excitation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Infrared to visible frequency upconversion fluorescence spectroscopy in high Er3+-doped AlF3-based fluoride glass, excited at 800 nm, is experimentally investigated. In AYF glass, the optimum Er3+ content for 550 nm emission is about at 6% mol ratio, which is 12% mol ratioin AZF glass. With the increasing of Er3+contenInfrared to visible frequency upconversion fluorescence spectroscopy in high Er3+-doped AlF3-based fluoride glass, excited at 800 nm, is experimentally investigated. In AYF glass, the optimum Er3+ content for 550 nm emission is about at 6% mol ratio, which is 12% mol ratioin AZF glass. With the increasing of Er3+content, the intensity ratios of the red emission to the green emission (Ir/Ig) is increased in AYF and AZF glasses, and the red emission intensity in these glasses depends on (Pex)1.6. They are mainly due to a cross-relaxation process between two erbium ions, one in the 4S3/2 and the other in the 4I9/2..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1689 (1999)
A New Kind of Quasi-Avalanche Up-Conversion Luminescence in Er3+ and Yb3+ Co-Doped ZBLAN Glasses
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The upconversion luminescence phenomena induced by 966 nm diode laser in Er:ZBLAN and Yb、 Er:ZBLAN glasses are studied. A new kind of quasi-avalanche up-conversion luminescence phenomenon is found. The results calculated from state rate equations are coincident with the experiment. When cross-relaxation P between Er3+ The upconversion luminescence phenomena induced by 966 nm diode laser in Er:ZBLAN and Yb、 Er:ZBLAN glasses are studied. A new kind of quasi-avalanche up-conversion luminescence phenomenon is found. The results calculated from state rate equations are coincident with the experiment. When cross-relaxation P between Er3+ ions is very small, up-conversion fluorescence intensity enhances gradually along with the increase of pumping laser power and tends gradually to saturation; when cross-relaxation P is large, duo to the large energy cross-transfer of Yb、 Er:ZBLAN glass between Yb3+ and Er3+ ions, the upconversion excitation velocity R of Er3+ ion is high enough to lead the up-conversion luminescence having a steep raise before it gets saturation. This is the phenomenon of “second uprising” observed in the experiment induced by quasi-avalanche effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1698 (1999)
Infrared Luminescence of Yb3+-Doped Ions in Floride Glasses (ZBLAN)
[in Chinese], [in Chinese], and [in Chinese]
Absorption and Luminescence properties of Yb3+ ions in fluorozirconate glasses were analyzed according to the measurement of absorption and emission spectra. The emission cross of Yb3+ was calculated and the reabsorption effect of Yb3+ ions was discussed. No concentration quenching was observed with increasing the concAbsorption and Luminescence properties of Yb3+ ions in fluorozirconate glasses were analyzed according to the measurement of absorption and emission spectra. The emission cross of Yb3+ was calculated and the reabsorption effect of Yb3+ ions was discussed. No concentration quenching was observed with increasing the concentration of Yb3+ ions in fluorozirconate glasses..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1894 (1999)
Nonlinear Optics
Two-Photon Resonant Three-Photon Ionization of Atomic Potassium
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By two-photon resonant three-photon ionization in atomic potassium, the ion current decay curve was measured. From the relation between ion current and multi-photon dynamic parameter, photo-ionization cross-section of 6S state in atomic potassium was determined. When excited with one-photon at 766.4 nm and 769.8 nm, thBy two-photon resonant three-photon ionization in atomic potassium, the ion current decay curve was measured. From the relation between ion current and multi-photon dynamic parameter, photo-ionization cross-section of 6S state in atomic potassium was determined. When excited with one-photon at 766.4 nm and 769.8 nm, the atomic potassium was ionized by energy pooling effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1604 (1999)
Effect of External Applied Alternating Field on the Transient Behaviour of Fundamental Harmonic of Photorefractive Space-Charge Field
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The “hopping” model is used to analyze the transient behaviours of fundamental harmonic of the space-charge field with external AC field. Exact and approximate dynamic analytical solutions are presented in the presence of sinusoidal AC field and square-wave field. For the applied AC field, it is found that the real parThe “hopping” model is used to analyze the transient behaviours of fundamental harmonic of the space-charge field with external AC field. Exact and approximate dynamic analytical solutions are presented in the presence of sinusoidal AC field and square-wave field. For the applied AC field, it is found that the real part of the fundamental space-charge field varies at the same frequency as that the applied field does, the imaginary part oscillates at twice the frequency. The photorefractive grating is phase-shift for high frequency of external applied alternating field. These results are in agreement with those derived from the band -transport model..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1608 (1999)
Optical Devices
Polarization Demultiplexing and Spatial Focusing with Diffractive Phase Element
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The design of diffractive phase elements (DPE′s) with polarization selectivity is presented, which can realize polarization demultiplexing and spatial focusing simultaneously. The design scheme is based on the general theory of amplitude-phase retrieval and Y-G iterative algorithm. A set of equations for determining thThe design of diffractive phase elements (DPE′s) with polarization selectivity is presented, which can realize polarization demultiplexing and spatial focusing simultaneously. The design scheme is based on the general theory of amplitude-phase retrieval and Y-G iterative algorithm. A set of equations for determining the modulation depth distribution of the surface-relief DPE is derived. Two model designs are carried out. The numerical simulations show that this suggested approach can achieve successfully the design of desired pattern..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1667 (1999)
Spatial Resolution Limit of A Raman Distributed Optical Fibre Temperature System
[in Chinese], [in Chinese], and [in Chinese]
So far, a truly distributed and commercialized optical fiber temperature system is based on Raman scattering. The spatial resolution limit of such a system is analyzed in the view of nonlinear fiber optics. It is found that a spatial resolution of 2 cm can be achieved for an 1km multi-mode system of 3.5 pW sensitivity So far, a truly distributed and commercialized optical fiber temperature system is based on Raman scattering. The spatial resolution limit of such a system is analyzed in the view of nonlinear fiber optics. It is found that a spatial resolution of 2 cm can be achieved for an 1km multi-mode system of 3.5 pW sensitivity and temperature resolution of ±1℃ within 0～400℃. With a sensitivity of better than 0.5 pW, the spatial resolution of a single-mode system will be better than that of above multi-mode system. Theoretically there is no restriction to introduce such a system into the application of moderate distance and high spatial resolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1673 (1999)
Polarization State Auto-Compensated Optical Fiber Current Transducer
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel bulk type of optical fiber current transducer (OFCT) is presented, in which the state of polarization of the fiber is auto-compensated. Theoretical analysis and experimental results are given. The new structure considerably improves the stability and the accuracy of OFCT.A novel bulk type of optical fiber current transducer (OFCT) is presented, in which the state of polarization of the fiber is auto-compensated. Theoretical analysis and experimental results are given. The new structure considerably improves the stability and the accuracy of OFCT..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1678 (1999)
A Novel Collimator for White Light
[in Chinese], and [in Chinese]
A new collimator is invented which is consisted of the graded-refractive-index(GRIN)-rod microarrays and diaphragm microarrays. The optical principle and the effects of material and structural parameters on collimating properties are studied theoretically. The results of calculation and preliminary experiments show thaA new collimator is invented which is consisted of the graded-refractive-index(GRIN)-rod microarrays and diaphragm microarrays. The optical principle and the effects of material and structural parameters on collimating properties are studied theoretically. The results of calculation and preliminary experiments show that the quasi-collimating light with the low diffuse angle and small chromatism can be obtained when the parameters are chosen appreciatively. The collimator can meet the needs of collimating backlight of LCD..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1682 (1999)
Quantum Optics
Study of Evanescent Light-Wave Cooling of Neutral Atoms in Gravitational Laser Trap with Monte-Carlo Simulation
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An efficient Sisyphus cooling and geometric cooling of three-level atoms in blue-detuned evanescent light-wave are discussed, and the kinetics processes of atom cooling in a pyramidal and conical hollow trap is studied by Monte-Carlo simulation.The results shows that (1) the atom-loss rate is decreased with the increasAn efficient Sisyphus cooling and geometric cooling of three-level atoms in blue-detuned evanescent light-wave are discussed, and the kinetics processes of atom cooling in a pyramidal and conical hollow trap is studied by Monte-Carlo simulation.The results shows that (1) the atom-loss rate is decreased with the increase of evanescent-wave laser power, (2) the final equilibrium temperature of atoms in the pyramidal trap is decreased as the reduce of detuning δ, and (3) there is a larger error between the Monte-Carlo results and theoretically-estimated ones when the judged width of evanescent light-wave is not wide enough. In addition, under the same conditions, the pyramidal atom trap is more efficient than the conical atom trap, which can obtain a lower atomic temperature and higher atomic density..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1585 (1999)
Relations Between Atomic Dipole Squeezing and Field Squeezing in the Coupling System of a Three-Level Atom
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By means of investigating the time evolution of atomic dipole squeezing and field squeezing in the system of a three-level atom interacting with a single cavity mode and a pair of cavity modes, the relations between atomic squeezing and field squeezing are examined. The properties of the squeezing transformation betweeBy means of investigating the time evolution of atomic dipole squeezing and field squeezing in the system of a three-level atom interacting with a single cavity mode and a pair of cavity modes, the relations between atomic squeezing and field squeezing are examined. The properties of the squeezing transformation between the atomic dipole quadrature components and the quadrature components are discussed. The conditions under which the initial atom in atomic dipole squeezing state can radiate squeezed light are presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1592 (1999)
Comparison of Squeezing Properties of a Cavity Field via Selective Different Atomic Ionization and Measurement
[in Chinese]
The interaction of a slow two-level Rydberg atom and a fast three-level Rydberg atom with a cavity field is studied. The results show that no squeezing exists for the selective fast atomic ionization and measurement, while for the slow atom, squeezing up to 25% can be obtained.The interaction of a slow two-level Rydberg atom and a fast three-level Rydberg atom with a cavity field is studied. The results show that no squeezing exists for the selective fast atomic ionization and measurement, while for the slow atom, squeezing up to 25% can be obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1599 (1999)
Rapid Communications
Red Electroluminesence Europium Polymer Complex
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Eu3+-containing polymer ternary complex was synthesized. And it was used as the emitting layer of the organic electroluminesence (OEL) device successfully. The red light of Eu3+ from the electrominesence (EL) device was seen at 16 V. A considerable difference between the EL and photoluminesence (PL) spectra was obsThe Eu3+-containing polymer ternary complex was synthesized. And it was used as the emitting layer of the organic electroluminesence (OEL) device successfully. The red light of Eu3+ from the electrominesence (EL) device was seen at 16 V. A considerable difference between the EL and photoluminesence (PL) spectra was observed. It was noticed that two spectra were very different. In PL spectrum the main peak was at 618 nm. But for the OEL spectrum, there are two peaks at 595 nm and 657 nm. The probable mechanism was discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1705 (1999)
[in Chinese]
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1709 (1999)
Scattering
A New Model of the Light Scattering in Biological Tissue for Visible and Near Infrared Region
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The optical model of biological tissue is discussed, in particular its description of optical scattering property. It is found that an equivalent particle size distribution function n(r) can be used to obtain more details and accurate understanding about optical scattering property of tissue. Under the Fraunhofer diffrThe optical model of biological tissue is discussed, in particular its description of optical scattering property. It is found that an equivalent particle size distribution function n(r) can be used to obtain more details and accurate understanding about optical scattering property of tissue. Under the Fraunhofer diffraction approximation, both the scattering coefficient μs and the scattering phase function S(θ) are educible from n(r). The scheme provides a new feasible method based on the light scattering techniques for particle size analysis to measure the optical properties of tissue..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 19, Issue 12, 1661 (1999)
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