Contents
2005
Volume: 25 Issue 2
31 Article(s)
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Atmospheric Optics and Oceanic Optics
Exact Rayleigh Scattering Calculation for Chinese Ocean Color and Temperature Scanner
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The accuracy of Rayleigh scattering calculation affects the quality of atmospheric correction of the ocean color remote sensing significantly, and it is essential to solve the vector radiative transfer equation (VRTE) in plane-parallel atmosphere to improve the accuracy of Rayleigh scattering calculation. This paper deThe accuracy of Rayleigh scattering calculation affects the quality of atmospheric correction of the ocean color remote sensing significantly, and it is essential to solve the vector radiative transfer equation (VRTE) in plane-parallel atmosphere to improve the accuracy of Rayleigh scattering calculation. This paper deduces the basic equations of VRTE with the adding-doubling method in detail, and expounds the principle of the adding-doubling method. By comparing with the exact Rayleigh scattering radiance derived from SeaWiFS (sea-viewing wide field-of-view sensor) exact Rayleigh scattering look-up table, it shows that the relative error of Rayleigh scattering calculation with the adding-doubling method is less than 0.5%, which meets the required accuracy of the atmospheric correction of ocean color remote sensing. Therefore, the adding-doubling method can be used to generate the Rayleigh scattering look-up table for Chinese ocean color and temperature scanner (COCTS). Finally, using the developed vector radiative transfer code with adding-doubling method, we had generated the exact Rayleigh scattering look-up tables for COCTS. Also, the vector radiative transfer code developed can be used to generate the exact Rayleigh scattering look-up table for Chinese second generation ocean color remote sensors which have high performances..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 145 (2005)
The Effect of Tracking Jitter on the Beam Spreading Induced by Atmospheric Turbulence
[in Chinese], and [in Chinese]
By using numerical simulation, we analyzed the effect of the transmitting system's tracking jitter on the beam spreading induced by atmospheric turbulence. The scaling relations that describe the effect of tracking jitter on the beam spreading are obtained. When the angle radius of the diffraction spot's the fiBy using numerical simulation, we analyzed the effect of the transmitting system's tracking jitter on the beam spreading induced by atmospheric turbulence. The scaling relations that describe the effect of tracking jitter on the beam spreading are obtained. When the angle radius of the diffraction spot's the first dark ring is big, the effect is relatively small. But when the angle radius is small, especially for turbulent effects being weak, the effect on the beam spreading is very distinct, and the magnitude of the beam spreading is mainly dependent on the jitter item of the scaling relations. In general, when turbulent effects are weak, the effect of tracking jitter is relatively distinct. However, with turbulent effects being gradually strong, gradually the magnitude of the beam spreading is mainly dependent on the turbulence item of the scaling relations. Therefore, through these scaling relations, we can quantitatively learn the effect of diffraction of transmitting system, tracking jitter and turbulent effects on beam spreading under different conditions. Moreover, we can obtain the scientific basis for the practical engineering systems' optimization design..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 152 (2005)
Diffraction and Gratings
Propagation of Gaussian Beam Limited by an Aperture
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Theoretically, the diffraction of Gaussian beam limited by the hard-edged aperture is studied and the diffraction distributions of Gaussian beam limited by the apertures with different calibers in Fresnel and Fraunhofer zones are analyzed in detail, and the evolution relationship of the diffraction of Gaussian beam andTheoretically, the diffraction of Gaussian beam limited by the hard-edged aperture is studied and the diffraction distributions of Gaussian beam limited by the apertures with different calibers in Fresnel and Fraunhofer zones are analyzed in detail, and the evolution relationship of the diffraction of Gaussian beam and the different size of the aperture in the different diffraction regions is obtained. The results show that the diffraction of Gaussian beam limited by the pupil function agrees with the Rayleigh diffraction when the caliber of the hard-edged aperture is small enough. These propagation rules of Gaussian beam limited by the aperture could promote the applications of Gaussian beam in the optical communication and the optical super-resolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 157 (2005)
Fiber Optics and Optical Communications
Determination of Surface Index of Graded-Index Waveguides
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Surface refractive index of a monotonously graded-index waveguide, which is greater than the effective index of the fundamental mode and cannot be measured in conventional m-line spectroscopy, is experimentally determined by employing the surface plasma wave (SPW) resonance technique based on analytical transfer matrixSurface refractive index of a monotonously graded-index waveguide, which is greater than the effective index of the fundamental mode and cannot be measured in conventional m-line spectroscopy, is experimentally determined by employing the surface plasma wave (SPW) resonance technique based on analytical transfer matrix (ATM) method. The index profiles predicted are more accurate than those obtained by the conventional inverse WKB (Wentzel, Kramers, Brillouin) method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 161 (2005)
Cross-Phase Modulational Instability with High-Order Dispersion
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The effect of third-order and fourth-order dispersion on cross-phase modulational instability based on extended nonlinear Schr??dinger equation is investigated. The result showsThe effect of third-order and fourth-order dispersion on cross-phase modulational instability based on extended nonlinear Schr??dinger equation is investigated. The result shows.
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 165 (2005)
In Situ Investigations of Thermal Poling Process of Optical Fibers
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Thermal poling of silica optical fibers can produce permanent second-order nonlinear and linear electooptic effect in fused silica fibers. In order to investigate the effects of processing parameters in thermal poling, an in situ testing system used for thermal poling process is constructed with an all polarization maiThermal poling of silica optical fibers can produce permanent second-order nonlinear and linear electooptic effect in fused silica fibers. In order to investigate the effects of processing parameters in thermal poling, an in situ testing system used for thermal poling process is constructed with an all polarization maintaining fiber Mach-Zehnder interferometer and is used for the in situ monitoring the thermal poling optical fibers. The effects of processing parameters in thermal poling, such as applied poling voltage, poling duration and ambient temperature, on the linear electrooptic effect created in the optical fiber are investigated. Experiments of the in situ monitoring show that the stronger the electric field in the fiber core is the higher linear electrooptic coefficient created in the fiber core could be. Considering the electrical breakdown of dielectric medium between electrodes for the structure of side polished fiber, the range of voltages of 3～4 kV could be applied during thermal poling. When around 3 kV is applied on the device with side polished fiber, the optimum poling duration is about 16 min and the optimum ambient temperature for thermal poling is about 190 ℃..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 169 (2005)
Dispersion Property Analysis of Square-Lattice Varying Microstructured Optical Fiber
[in Chinese], [in Chinese], and [in Chinese]
A new square-lattice varying microstructured optical fiber is presented. Using finite-difference time-domain method, the dispersion curves of five-ring varying microstructured optical fiber are caculated, hole-to-hole space of which is 2.0 μm and 2.5 μm, the least diameter is 0.4 μm, 0.6 μm, 0.7 μm, 0.8 μm and 1.0 μm, A new square-lattice varying microstructured optical fiber is presented. Using finite-difference time-domain method, the dispersion curves of five-ring varying microstructured optical fiber are caculated, hole-to-hole space of which is 2.0 μm and 2.5 μm, the least diameter is 0.4 μm, 0.6 μm, 0.7 μm, 0.8 μm and 1.0 μm, and the diameter increases from the first ring to the fifth ring by a pitch of Δd=0.1 μm and Δd=0.2 μm respectively. The result shows that the new square-lattice varying microstructured fiber is better than the square-lattice no-varying microstructured fiber in controlling the dispersion and dispersion slope in the wide wavelength, the dispersion curve of which can remain flatter and lower in 1400～2000 nm. When the third ring diameter of varying microstructured fiber has the same value with the diameter of no-varying microstructured fiber, the lowest and flattest dispersion curve is obtained, in this case, the dispersion value is about 30 ps/(km?nm) and Δd=0.2 μm. So the flatter and lower dispersion curve can be realized by adjusting the diameters, distribution of air holes, and the hole-to-hole space..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 174 (2005)
High Rate Chaos Secure Communication System of Multiple-Quantum-Well Lasers
[in Chinese]
A high rate all-optical secure communication scheme of chaotic multiple-quantum-well lasers from external injection light is studied. The system synchronization equation is derived. Synchronization is theoretically demonstrated and numerically achieved. Synchronization time is shortened and synchronization stability isA high rate all-optical secure communication scheme of chaotic multiple-quantum-well lasers from external injection light is studied. The system synchronization equation is derived. Synchronization is theoretically demonstrated and numerically achieved. Synchronization time is shortened and synchronization stability is boosted with the feedback coefficient increasing in numerical simulations. Models of all-light chaos masking and chaos shift keying modulation-demodulation with multiple-quantum-well lasers are investigated for secure communications, respectively. Chaos analog secure communication with a sinusoidal signal of 0.2 GHz modulation frequency, chaos digital secure communication with a digital signal of 20 Gb/s modulation rate and chaos shift keying secure communication with the modulation rate 0.05 Gb/s are numerically simulated, respectively. It is found that the system shows a good ability of robust and anti-code-breaking. Synchronous error is numerically calculated in chaos digital communications with the modulation bandwidth of 20 Gb/s in the modulation-demodulation processes and the modulation rate characterization is analyzed to conclude that lower synchronous error under high bit rate and the maximum bit rate limit of 1 Gb/s in chaos shift keying communication..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 179 (2005)
Fourier Optics and Signal Processing
Demodulation of the Optical Fiber Fabry-Perot Sensor Based on Fourier Transform
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the principle of two-beam interferometer, the demodulating theory of optical fiber Fabry-Perot sensor illuminated by Gauss distributed optical source was demonstrated via Fourier transform method. According to the characteristic of Gauss distributed optical source，the feasibility of measuring cavity length wasBased on the principle of two-beam interferometer, the demodulating theory of optical fiber Fabry-Perot sensor illuminated by Gauss distributed optical source was demonstrated via Fourier transform method. According to the characteristic of Gauss distributed optical source，the feasibility of measuring cavity length was presented by directly applying an fast Fourier transform (FFT) algorithm to the data sampled at equal optical wavelength interval and using the relation of cavity length and the peak frequency in the frequency domain. The demodulation precision was increased with frequency spectrum interpolating technology, and the experimental verification was accomplished with the help of the demodulating system constituted by broadband light source and spectrometer etc. The measured data are coincident well with theoretically calculated data..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 186 (2005)
Instrumentation, Measurement and Metrology
Measurement of Flow Velocity Using Self-Mixing Speckle Interference Generated in Laser Diode
[in Chinese], [in Chinese], and [in Chinese]
The theoretical analysis and experimental result of self-mixing laser speckle interference (SMSI) velocimeter for flow measurement are presented based on the theory of Fabry-Pérot (F-P) cavity model. The mean speckle frequency reflects the activity of flow. The variation of gain and distribution of probability denThe theoretical analysis and experimental result of self-mixing laser speckle interference (SMSI) velocimeter for flow measurement are presented based on the theory of Fabry-Pérot (F-P) cavity model. The mean speckle frequency reflects the activity of flow. The variation of gain and distribution of probability density are given. The computer simulation shows the linear relation between the mean speckle frequency and velocity of flow, and experimental result proves relation. The velocity of glutin solution is measured by this linear relation. The effect of background and concentration of flow are considered in the experiment. When the concentration of flow is appropriate, the error of experiment is less than 8%. The results of experiment show this method is useful for measurement of flow..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 190 (2005)
Methodological Disquisition of Spherical Fine Metrical Precision
[in Chinese], [in Chinese], and [in Chinese]
With developing of shortwave optics and more requirement of lofty precision optical machine, the processing and measurement of fine precision surface are becoming important. But in common interferometry, the metrical precision of spherical surface mainly Sepends on the precision of reference surface. So an absolute calWith developing of shortwave optics and more requirement of lofty precision optical machine, the processing and measurement of fine precision surface are becoming important. But in common interferometry, the metrical precision of spherical surface mainly Sepends on the precision of reference surface. So an absolute calibration method has been described (Jensen in 1973) that is ideally suited to a real-time interferometer to wipe off all additive aberration. Based on the absolute calibration theory a method which rotates the wavefront by using Zernike polynomials is put forward, and detailed projects are given. We get fine precision by measuring surface of small protruding spherical surface with precision above λ/37, and break the localization of standard lens which λ/20 is the best. The method can be used to get fine metrical precision of spherical surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 195 (2005)
Research of a Novel Principle on Sea-Water Salinity Measurement Based on Refractive Index Change
[in Chinese], and [in Chinese]
A novel device measuring seawater salinity is developed, based on techniques of surface plasmon resonance (SPR) and relation between its salinity and refractive index. In the device, a prism made of K9 glass is used as substrate, and a film of Ag (55nm) is deposited on one side of the prism; after that, two flowing celA novel device measuring seawater salinity is developed, based on techniques of surface plasmon resonance (SPR) and relation between its salinity and refractive index. In the device, a prism made of K9 glass is used as substrate, and a film of Ag (55nm) is deposited on one side of the prism; after that, two flowing cells are built on the Ag film, one serves as sample solution, and the other as distilled water. Under the excitation of white light, SPR occurs in two areas at different wavelengths. Although the refractive index of seawater is determined not only by its salinity, but also by its temperature, and sample solution and distilled water have the same temperature. If the difference of resonance wavelengths (Δλ) is utilized to indicate the salinity, the affection by temperature drift could be eliminated. Theoretical analysis and experimental result verify the feasibility of the device..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 199 (2005)
Calibration of the Measurement System Based on Modulation Measurement Profilometry
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In modulation measurement profilometry (MMP), the shape of a testing object is directly decoded from the fringe modulation instead of phase value calculated by fringes recorded from the surface of a diffuse object. A calibration procedure of the measurement system is presented based on MMP. Several parallel planes are In modulation measurement profilometry (MMP), the shape of a testing object is directly decoded from the fringe modulation instead of phase value calculated by fringes recorded from the surface of a diffuse object. A calibration procedure of the measurement system is presented based on MMP. Several parallel planes are used to establish the height-mapping between the measured height and the true height of the object. A look-up table of the height-mapping coefficient is established and stored in the measurement system. The measuring results show that the system error is compensated for and one order higher accuracy can be achieved by the presented system calibration method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 203 (2005)
Three-Dimensional Shape Measurement for Rotating Blade Using Stroboscopic Structured Illumination
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Three-dimensional digitized description of high-speed motion objects is very useful in study its motion and deformation. An optical method of rotating fan blade shape and deformation measurement is proposed, which was based on Fourier transform profilometry (FTP) and stroboscopic effect, and than is verified by experimThree-dimensional digitized description of high-speed motion objects is very useful in study its motion and deformation. An optical method of rotating fan blade shape and deformation measurement is proposed, which was based on Fourier transform profilometry (FTP) and stroboscopic effect, and than is verified by experiment on a domestic electric fan. The results of authors' experiment proposed show that FTP can reconstruct the rotating fan blade shape efficiently and reveal the deformation clearly at different times by using stroboscopic light structured illumination. This method is suitable for wide use in studying rapid periodic motion..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 207 (2005)
Lasers and Laser Optics
15-Wavelength Brillouin Erbium-Doped Fiber Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Brillouin erbium-doped fiber laser is a novel kind of fiber laser with multi-wavelength output, which can produce a laser comb with spacing of 0.08 nm (10 GHz) using a combination of Brillouin gain and linear gain in erbium-doped fiber. The stabled 15-wavelength output are obtained with the Brillouin pump of 1.7 mWThe Brillouin erbium-doped fiber laser is a novel kind of fiber laser with multi-wavelength output, which can produce a laser comb with spacing of 0.08 nm (10 GHz) using a combination of Brillouin gain and linear gain in erbium-doped fiber. The stabled 15-wavelength output are obtained with the Brillouin pump of 1.7 mW and 980 nm-pump of 300 mW. The laser can be utilized in optical sensor, spectrum analyser and deuse wavelength division multiplexer system as laser source. The experiment also demonstrates that the number of output wavelength will increase when 980 nm pump increase and the power of multi-wavelength output mainly comes from the EDFA gain with little influence from Brilloum gain..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 212 (2005)
Generation of 15 fs Pulses from Ti∶Sapphire Laser with Optimized Gires-Tournois Mirrors
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
According to the mode-locked femt second Ti∶sapphire laser pulse compression, the characteristics and principles of dispersion compensation of negative dispersion mirrors were introduced. Optimized Gires-Touronis (OG-T) mirrors were designed and fabricated. OG-T mirrors were deposited by means of ion-beam sputtering onAccording to the mode-locked femt second Ti∶sapphire laser pulse compression, the characteristics and principles of dispersion compensation of negative dispersion mirrors were introduced. Optimized Gires-Touronis (OG-T) mirrors were designed and fabricated. OG-T mirrors were deposited by means of ion-beam sputtering onto superpolished substrates. The transmittance and group dispersion delay of first fabricated OG-T (OGT#1) mirrors were measured. Film coating parameters were adjusted according with design value. After that, second fabricated OG-T (OGT#2) mirrors were fabricated. Dispersion was compensated by 5 bounces during 3 OG-T mirrors from mode-locked femtosecond Ti∶sapphire laser. 32 fs pulse (46 nm spectrum width) and 15 fs pulse (91 nm spectrum width) were obtained respectively by OGT#1 and OGT#2. The excellent features of negative dispersion mirrors were proved by the experiment and the fine chirped mirrors could be fabricated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 216 (2005)
OPTICAL DATA STORAGE
Dual-Wavelength Optical Image Storage with Bicolor Fulgides Film
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Two types of photochromic fulgide compounds [(1,2,4-trimethyl-5-phenyl)-3-pyrryl-ethylidene (isopropylidene) fulgide and (p-N,N-dimethylphenyl-2-methyl)-3-oxazoleyl-ethylidene (isopropylidene) fulgide] were used to prepare single layer bicolor PMMA composite film. The experiment demonstrated that two different images cTwo types of photochromic fulgide compounds [(1,2,4-trimethyl-5-phenyl)-3-pyrryl-ethylidene (isopropylidene) fulgide and (p-N,N-dimethylphenyl-2-methyl)-3-oxazoleyl-ethylidene (isopropylidene) fulgide] were used to prepare single layer bicolor PMMA composite film. The experiment demonstrated that two different images could be recorded on the bicolor composite film at the same area by using two different wavelengths (650 nm and 488 nm) respectively. When using the corresponding wavelength 650 nm or 488 nm to readout the two stored images on the film, each wavelength can obtain a high contrast ratio image and the two images with little crosstalk. This experiment confirmed that it was feasible to store and readout two images at the same area of the bicolor photochromic fulgide material..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 220 (2005)
Optical Design and Fabrication
Method for Improving the Performance of Wide Screen Projection Display Illumination System
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Illumination system is an important component of projection display system, and decides the whole brightness and uniformity of the whole system. Fly-eye system is a commonly used illumination configuration in liquid crystal display (LCD) projectors. In traditional fly-eye illumination systems, the elemental lens of flyIllumination system is an important component of projection display system, and decides the whole brightness and uniformity of the whole system. Fly-eye system is a commonly used illumination configuration in liquid crystal display (LCD) projectors. In traditional fly-eye illumination systems, the elemental lens of fly-eye always has the same aspect ratio as the LCD device. But when applied to wide screen projection systems, this will lead to a certain energy loss. This paper presents a new method for improving the performance of wide screen projection display illumination systems, which introduces cylinder lenses. Results of simulation show that a total increment of about 5% to 10% of the output lumens is available with this improved fly-eye system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 224 (2005)
Optical Devices
Research on Chromatic Dispersion Characteristic of Thin Film Filter
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on signal processing theory, the filtering characteristic of thin film filter was researched in detail. Thin film filter is minimum phase filter (MPF) and Hilbert transform law is related with the amplitude response and the phase response. So the phase response can be reconstructed from its amplitude response andBased on signal processing theory, the filtering characteristic of thin film filter was researched in detail. Thin film filter is minimum phase filter (MPF) and Hilbert transform law is related with the amplitude response and the phase response. So the phase response can be reconstructed from its amplitude response and then the characteristic of chromatic dispersion can be achieved. To validate the theoretical analysis, a test system for group velocity delay was set up based on RF modulation. As an example, the group velocity delay of a 100 GHz 33CH thin film filter was tested. The experimental result matched with the theoretical result very well through contrasting analysis. At last, an analysis of the characteristic of chromatic dispersion of thin film filter was also provided..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 228 (2005)
Preparation of a Pin-Cushion Two-Dimensional Position Sensitive Detector
[in Chinese], [in Chinese], and [in Chinese]
The basic design principle of a pin-cushion two-dimensional position sensitive detector (PSD)――Gear′s theorem is testified, and the position formula of this type of PSD is derived. Moreover, presented in this paper are the fabrication process and device performance of the pin-cushion PSD. The pin-cushion PSD devices (sThe basic design principle of a pin-cushion two-dimensional position sensitive detector (PSD)――Gear′s theorem is testified, and the position formula of this type of PSD is derived. Moreover, presented in this paper are the fabrication process and device performance of the pin-cushion PSD. The pin-cushion PSD devices (sensitive area 8 mm×8 mm) fabricated with IC technology show good optoelectronic properties, excellent position linearity and accuracy. The dark current is 15 nA when the reverse bias is 5 V. The peak sensitivity is over 0.6 A/W. Within 75% sensitive area, the measured RMS of position error is about 0.135 mm, and its nonlinearity characterized with RMS of position error is around 1.1%, almost improved by one order of magnitude compared with that of the tetra-lateral two-dimensional PSD..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 233 (2005)
Physical Optics
Study on Optic Attenuation with Foam Interfering Screens
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Foam interfering screens (FIS)is a new technique to solve the main problems of multi-band interfering techniques. The method to discharge FIS was given. Its optic attenuation performance was measured by the integration test system of guided missile. The result is that FIS with its size variable from 1 cm to 45 cm can mFoam interfering screens (FIS)is a new technique to solve the main problems of multi-band interfering techniques. The method to discharge FIS was given. Its optic attenuation performance was measured by the integration test system of guided missile. The result is that FIS with its size variable from 1 cm to 45 cm can make TV&IR-guided missiles invalid, and the diameter of air bladder in FIS is the only main factor to influence the attenuation effect. It shows that FIS could be effective to attenuate optical transmission in spotting and weapon guiding. And it can offer the theoretical and experimental basis for the tactics application of FIS..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 237 (2005)
Polarization of Reflected Light by Earth Objects
[in Chinese], [in Chinese], and [in Chinese]
Compared with the traditional luminosity and radiation remote sensing methods, polarization measurement has many unique advantages. To achieve visible-infrared polarimetric spectra, the polarimetric spectra of six objects are measured with Stokes parameter method, including both natural objects and man-made objects. ThCompared with the traditional luminosity and radiation remote sensing methods, polarization measurement has many unique advantages. To achieve visible-infrared polarimetric spectra, the polarimetric spectra of six objects are measured with Stokes parameter method, including both natural objects and man-made objects. Their polarimetric spectra are compared in detail and the forming mechanism are analysed, too. The results show the significance of polarization measurment in remote sensing and object discrimination..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 241 (2005)
Analysis of Diffractive Image Field in Thick Film Photo-Resist by Using Fourier Modal Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
According to the lithographic characteristics of thick film photo-resist, a novel physical model is established. Then Fourier model method, mostly applied to study the diffractive properties of gratings is adopted to analyze the diffractive image field in thick film photo-resist. The factors such as reflection and tranAccording to the lithographic characteristics of thick film photo-resist, a novel physical model is established. Then Fourier model method, mostly applied to study the diffractive properties of gratings is adopted to analyze the diffractive image field in thick film photo-resist. The factors such as reflection and transmission at the interface, complex diffraction in the photo-resist, are taken into account. This method has higher computing precision and smaller computation cost. Numerical simulation results show that the distribution of diffractive image field is relevant to that of complex refractive index. As a result, it is reasonable to regard the thick film photo-resist as grating with variable refractive index during exposure process..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 246 (2005)
Quantum Optics
The Time-Dependent Atom-Field Coupling J-C Model with an Initial Squeezing State
[in Chinese], and [in Chinese]
The quantum statistical properties of two-photon Jaynes-Cummings model with a time-dependent atom-field coupling coefficient are discussed under the initial squeezing state of the light field. Especially, the time evolution of the atomic population inversion and the squeezing properties of the cavity field is investigaThe quantum statistical properties of two-photon Jaynes-Cummings model with a time-dependent atom-field coupling coefficient are discussed under the initial squeezing state of the light field. Especially, the time evolution of the atomic population inversion and the squeezing properties of the cavity field is investigated. The effects of the atom-field coupling coefficient, the squeezing parameter and phase on these properties are also discussed. When the squeezing coefficient of the initial field increases, the frequency of collapse-revival in atomic population inversion increases, and the amplitude of revival decreases. When the atom-field coupling coefficient changes slowly, the collapse-revival is delayed, and the squeezing of the field is lost gradually. When the coupling coefficient changes rapidly, it accelerates the collapse-revival phenomena, and the squeezing parameter oscillates with time, the squeezing of the field appears repeatedly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 251 (2005)
Spectroscopy
High-Resolution Absorption Spectrum of Water Vapor near 1.315 μm
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The study of absorption property of water vapor is valuable for laser communication and transmission of laser. The study of spectra of water vapor is important to theoretical and engineering utility. The high-resolution absorption spectra of water vapor near 1.315 μm wavelength were recorded accurately using a DFB (disThe study of absorption property of water vapor is valuable for laser communication and transmission of laser. The study of spectra of water vapor is important to theoretical and engineering utility. The high-resolution absorption spectra of water vapor near 1.315 μm wavelength were recorded accurately using a DFB (distributed-feedback) diode laser operating at 1.315 μm and a White type multi-pass cell. The diode laser has narrow line width and wide tune range. Total optical length in the multi-pass cell call be varied in a wide range, the maximum optical length is 1097 nm. Using the recorded spectra, line shape parameters of some water vapor re-vibrational overtones near 1.315 μm were measured at room temperature, line strengths, line positions and self-broadening coefficients were obtained. The measured data agree well with that in the HITRAN database. Advanced electronic technology and computer control technology were used in experiment which improved the efficiency greatly and assured the reliability of the measured data..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 256 (2005)
Emission Spectra of C2 in the Process of Deflagration To Detonation Transition of Epoxypropane
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The process of deflagration to detonation transition (DDT) of epoxypropane is studied in the shock tube. The study aimed to obtain the spectra information about the intermediate products of epoxypropane after fast reaction. In the experiment, by using an advanced intensified CCD spectroscopic detector and self-made eleThe process of deflagration to detonation transition (DDT) of epoxypropane is studied in the shock tube. The study aimed to obtain the spectra information about the intermediate products of epoxypropane after fast reaction. In the experiment, by using an advanced intensified CCD spectroscopic detector and self-made electrical single pulse trigger, emission spectra of C2 with bandheads 516.52 nm,512.94 nm, 563.55 nm,558.55 nm,554.07 nm,550.19 nm, and 544.77 nm have been detected in the DDT process of epoxypropane with exposure time of 2 μs. Two vibrational band sequences (Δν=-1，0) of d3∏g-a3∏u are identified. And the experiment is performed many times; from the pressure sign monitored by pressure sensors, it can be nearly confirmed the sameness of DDT in the 500～570 nm region. Furthermore, this experiment indicate that C2 radical is one of the main products of epoxypropane in the DDT process, and the several possible reaction passage are given, too..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 261 (2005)
Magnetic Rotation Cavity Enhanced Spectroscopy
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
To improve the detection sensitivity in the conditions of weak absorption and/or short absorption path, a highly sensitive spectroscopy, namely magnetic rotation cavity enhanced absorption spectroscopy, was developed by combining cavity enhancement with magnetic rotation techniques together, where a ring shape externalTo improve the detection sensitivity in the conditions of weak absorption and/or short absorption path, a highly sensitive spectroscopy, namely magnetic rotation cavity enhanced absorption spectroscopy, was developed by combining cavity enhancement with magnetic rotation techniques together, where a ring shape external cavity was adopted as the signal enhancement to avoid the perturbation of the return beam to the laser source. The qualifications of mode matching together with the dependence of the enhanced factor on the mirrors' reflectivity and the cavity loss were presented; moreover, the process of the spectroscopic signal in the experiments was also discussed. As an example, this spectroscopy was employed to observe the spectrum of the triply forbidden transition of O2, and the minimum detectable absorption was measured to be about 4.5×10-8 (1 s integrated time) with 95% coupling efficiency, 48 finess and 13% total loss of the cavity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 265 (2005)
Thin Films
Design and Deposition of Broadband IR Antireflection Coatings on ZnS Lenses
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Infrared (IR) antireflection (AR) coatings are indispensable to optical and electrooptical system, especially to the systems such as IR camera. They are very important for the system to improve the energy output and the optical performance. ZnS is usually used to make lenses for IR systems because of its wideband transInfrared (IR) antireflection (AR) coatings are indispensable to optical and electrooptical system, especially to the systems such as IR camera. They are very important for the system to improve the energy output and the optical performance. ZnS is usually used to make lenses for IR systems because of its wideband transmission region. But as a substrate, it is very difficult to deposit AR coatings on ZnS in IR region, especially for the durability. The AR coating is for the ranges of 3.5～3.9 μm and 9～12 μm, and the transmittance required of the spectra is more than 90%. Because there are very few materials that have a wideband transparency available for the long wavelength IR region, it is much more difficult to obtain a good coating which has both good transmittance and good durability. Giving attention to both choosing IR coating materials and meeting the spectra requirement, yttrium fluoride (YF3) was adopted as low-index material at last. But the severe stresses of YF3 would result in chapping if there was not a suitable depositing condition. This problem was solved by utilizing improved techniques such as mixed-vaporizing, ion beam assisted deposition and feasible temperature. The durability, stability and transmittance are all advanced..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 270 (2005)
Design of Depolarization Thin Film Cutoff Filters
[in Chinese], [in Chinese], and [in Chinese]
The separation between s- and p-polarization components is an invariable effect in thin film edge filters used for tilted incidence. So it is difficult for many applications, especially for optical communication. A novel design method is put forward and the cutoff filters with depolarization at incidence angle of 45The separation between s- and p-polarization components is an invariable effect in thin film edge filters used for tilted incidence. So it is difficult for many applications, especially for optical communication. A novel design method is put forward and the cutoff filters with depolarization at incidence angle of 45° are achieved. The polarization separation at transmittance 50% for a long-wave-pass filter and a short-wave-pass filter is 0.3 nm and 0.1 nm respectively. The design method is based on a broad band Fabry-Pérot thin film interference filter in which higher or lower interference band in both sides of main transmittance peak can be used for an initial design of long-wave-pass filter or short-wave-pass filter and then can be refined to reduce the transmittance rippers. The spacer 2H2L2H or 2L2H2L of the interference filter is usually taken. Moreover, the method for expanding bandwidth of rejection and transmission is explained. The bandwidth of 200 nm for both rejection region and transmission band is obtained at wavelength 1550 nm. In this way, the long-wave-pass and short-wave-pass edge filters with zero separation between two polarization components can easily be gotten and fabricated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 274 (2005)
Spectral Response Characteristic Calculation of Birefringent Thin Films on Berreman Matrix
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Berreman matrix method is applied to determine the transmission and reflection characteristics of birefringent thin films. Standard boundary conditions are imposed on resultant electric- and magnetic-field vectors at interfaces. A simplified analytic expression for the 4×4 propagation matrix of a general homogThe Berreman matrix method is applied to determine the transmission and reflection characteristics of birefringent thin films. Standard boundary conditions are imposed on resultant electric- and magnetic-field vectors at interfaces. A simplified analytic expression for the 4×4 propagation matrix of a general homogeneous biaxial layers is derived. Thus simple matricial relations are obtained for transmitted and reflected electric-field amplitudes of birefringent thin films. These matricial recurrence relations include multiple reflections while dealing with total fields. This provides support for a more general anisotropic multilayer film system. Example calculations are presented for a special case of isotropic-biaxial-isotropic film system. And these should be the foundation of further research and the design of birefringent thin-film devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 279 (2005)
Photoluminescence Performance as a Function of Ytterbium Doping Concentration from Er/Yb Co-Doped Al2O3 Films
[in Chinese], and [in Chinese]
Er/Yb co-doped Al2O3 films with variant Yb concentrations, which are controlled through adjusting the area ratio of Yb to Er in the surface of the target, are fabricated by radio-frequency (RF) reaction magnetron sputtering technique. The reliability of composition control of Er/Yb ratio in film prepapration and the inEr/Yb co-doped Al2O3 films with variant Yb concentrations, which are controlled through adjusting the area ratio of Yb to Er in the surface of the target, are fabricated by radio-frequency (RF) reaction magnetron sputtering technique. The reliability of composition control of Er/Yb ratio in film prepapration and the influeme of Yb doping concentration on room temperature photoluminescence (PL) spectral intensity and distribution of Er/Yb co-doped Al2O3 films are mainly investigated. Rutherford backscattering spectroscopy (RBS) and energy dispersive X-ray analysis (EDX) are used to determine the composition of the films. It is shown that the concentration ratio of Yb to Er in the films accorded with the area ratio of Yb to Er in the surface of the target. The room temperature PL spectrum of the films after annealing at 1000 ℃ for 2 h shows that the PL intensity of Er3+ can be enhanced by Yb doping. The PL intensity and full width at half maximum (FWHM) reaches its maximum when the area ratio of Yb to Er reaches to 4∶1. The results of the research show that, as far as Al2O3 films are concerned, appropriate concentration of Yb/Er not only improves the luminescence efficiency of the films, but also enhances the channel bandwidth..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 2, 284 (2005)
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