Journals >Acta Photonica Sinica
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2005
Volume: 34 Issue 11
38 Article(s)
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Research Article
LD Pumped Cr:YAG Passively Q-switched 556nm Yellow Laser
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1.112μm laser transition of Nd∶YAG was obtained by restrained the stronger stimulated laser transitions through cavity coating design. A LD pumped, LBO intracavity frequency doubled and Cr∶YAG passively Q-switched laser at 556 nm were reported.At the incident pump power of 1.6 W, the laser produced pulses of 48 ns dura1.112μm laser transition of Nd∶YAG was obtained by restrained the stronger stimulated laser transitions through cavity coating design. A LD pumped, LBO intracavity frequency doubled and Cr∶YAG passively Q-switched laser at 556 nm were reported.At the incident pump power of 1.6 W, the laser produced pulses of 48 ns duration at 556 nm, with a repetition rate of 8.9 kHz,meanwhile the average output power was 51 mW and the highest yellow peak power was about 119 W..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1601 (2005)
High Power Single Mode Er3+:Yb3+ Co-doped Double Cladding Fiber Lasers
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Numerical analysis and experimental results of erbium-ytterbium co-doped double-cladding fiber lasers (EY-DCFLs) with single mode output were presented. Numerical analysis of this EY-DCFL, based on the rate and propagation equations,was performed firstly in order to optimize its properties theoretically. Then experimenNumerical analysis and experimental results of erbium-ytterbium co-doped double-cladding fiber lasers (EY-DCFLs) with single mode output were presented. Numerical analysis of this EY-DCFL, based on the rate and propagation equations,was performed firstly in order to optimize its properties theoretically. Then experimental research was done of this EY-DCFL by using the same conditions such as pump power, fiber length, and dichroic mirror. The output powers as functions of the input pump power and fiber length were described, as well as the output wavelength vs the fiber length. The maximum output power was about 2.2 W lasing at 1566 nm by using a 6.30 m fiber, with an overall optical to optical conversion efficiency of 22%, which were 33% lower than the calculated.
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1605 (2005)
Physical Analyses of Optical Breakdown and Plasma Formation in Water Induced by Laser
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The physical mechanism of optical breakdown induced by short-pulse laser in water was analyzed, and the laser breakdown threshold was determined with a numerical calculating method for the rate equation of free electron density. The numerical calculating results were compared to experimentally measured breakdown threshThe physical mechanism of optical breakdown induced by short-pulse laser in water was analyzed, and the laser breakdown threshold was determined with a numerical calculating method for the rate equation of free electron density. The numerical calculating results were compared to experimentally measured breakdown threshold of pure water and impure water by nanosecond,picosecond and femtosecond laser pulses in the visible and near-infrared.On this basis, the evolution of the electron density and the absorption coefficient and energy density of the plasma during the laser pulse were gotten. A good quantitative agreement was found between calculated and measured values..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1610 (2005)
Optical Transmission Spectrum of Thue-Morse structure Containing Negative Index Materials
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The transmission spectrum of Thue-Morse photonic crystals constructed by positive and negative index materials alternately was investigated.The transmittance was calculated by the recursion relations of the transfer matrix elements.Numerical analyses show that a zero-n gap exists in the TM multilayer system.Comparing wThe transmission spectrum of Thue-Morse photonic crystals constructed by positive and negative index materials alternately was investigated.The transmittance was calculated by the recursion relations of the transfer matrix elements.Numerical analyses show that a zero-n gap exists in the TM multilayer system.Comparing with the Bragg gap,this gap is less sensitive to the incident angle and the polarization.The position of gap will not change with the order number of the TM sequence.Meanwhile,the field distribution is investigated for completely transparent states.The field distributions are analogous to the lattice structure..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1615 (2005)
The Influence Analyses of Superstrong Laser Parameter to Refraction Coefficient of Plasma
The “near static state” cold plasma model of the interaction between the super-stength laser and the plasma was analysed.The refraction coefficient of plasma relativing to rectangle-pulse laser and un-rectangle-pulse laser were worked out.The influence of laser parameter to the refraction coefficient of plasmawasdiscusThe “near static state” cold plasma model of the interaction between the super-stength laser and the plasma was analysed.The refraction coefficient of plasma relativing to rectangle-pulse laser and un-rectangle-pulse laser were worked out.The influence of laser parameter to the refraction coefficient of plasmawasdiscussed.Theresultsarefounded:1)Whenthesizeofunitaryvectorpotentialislargerthan1.4,under the same laser strength,the electrostatic potential of rectangle laser is larger than that of the un-rectangle laser.And the less of laser strength is,the less is the discrepancy between the two;2)Under the same laser strength, the refraction coefficient aroused by rectangle-pulse laser is much bigger than that aroused by un-rectangle-pulse laser;3)No matter which kind the pulse laser is,so long as the laser strength increases,the refraction coefficient will increase too.But only the rectangle-pulse laser is the most easy to make the refraction coefficient reach 1;4)When the laser strength is certain,with the inc.
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1620 (2005)
The Research of Digital Delay Signal Integrity in Laser Targeting
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In order to solve the problem of signal integrity displayed in the design high-speeding digital circuit,a delay distribution method of high-speeding digital circuit was discussed in this paper.The maximum matching length of termination trace based on the transportation theory was set up,which was helpful to decrease thIn order to solve the problem of signal integrity displayed in the design high-speeding digital circuit,a delay distribution method of high-speeding digital circuit was discussed in this paper.The maximum matching length of termination trace based on the transportation theory was set up,which was helpful to decrease the termination reflection in PCB designing.The crosstalk model and the termination means based on the electronics theory were also discussed, which was used to eliminate the crosstalk.Analyzing the composite disturbance of noise current I_n and transient load current I_L,some restrain methods were taken, which ensured the delay signal integrity..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1625 (2005)
Performance Analysis of Planar Curved Waveguide Coupler
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Based on coupled mode theory and the structure of curved waveguide coupler (CWC), the performance of planar CWC was analyzed.The result shows that the two variables,bending radius and minimum space,increase the flexibility of waveguide device design.By the modulation of effective coupling length,CWC can accommodate widBased on coupled mode theory and the structure of curved waveguide coupler (CWC), the performance of planar CWC was analyzed.The result shows that the two variables,bending radius and minimum space,increase the flexibility of waveguide device design.By the modulation of effective coupling length,CWC can accommodate wider multiplexing bandwidth than parallel straight waveguide coupler (SWC) in wavelength division multiplex (WDM).The effect of bending radius and minimum space on the multiplexing bandwidth of curved coupler was studied numerically,which provided a certain theoretical basis for design and fabrication of devices..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1629 (2005)
Study on Measuring Sensitivity of Fiber-optic Hydrophone
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A set of easy-used calibrating apparatus for fiber-optic hydrophone′s sensitivity was invented,and a convenient measuring method of comparison was proposed.The probes of standard piezoelectric hydrophone and fiber-optic hydrophone were placed in the same sound field ,then the outputs of the two probes were linked to thA set of easy-used calibrating apparatus for fiber-optic hydrophone′s sensitivity was invented,and a convenient measuring method of comparison was proposed.The probes of standard piezoelectric hydrophone and fiber-optic hydrophone were placed in the same sound field ,then the outputs of the two probes were linked to the digital oscilloscope for comparison measure.The research shows that the resonant peak can be removed from the working frequency range which is from 3 ~ 1000 HZ when the wall thickness of the metallic cylinder in the vibrating system is more than 10 mm or 1/10 of the cylinder′s outer diameter.Applying this setting as well as comparison method ,the calibration system is simple and the process of calibration is quick,then the error is less than 0.5 dB,which is in the demand of the calibration for fiber-optic hydrophone′s sensitivity..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1633 (2005)
Preparation of Polymer Microlenses Array by using Drop-on-Demand Technology
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High-quality refractive microlens and microlens array have been fabricated using drop-on-demand and in-situ thermal polymerization technology with polymer PMMA and its monomer MMA.Microlenses diameters and heights range from d=1 mm to 3 mm,and h=100 μm to 400 μm,respectively.A focal length ranges from 1mm to 4 mm approHigh-quality refractive microlens and microlens array have been fabricated using drop-on-demand and in-situ thermal polymerization technology with polymer PMMA and its monomer MMA.Microlenses diameters and heights range from d=1 mm to 3 mm,and h=100 μm to 400 μm,respectively.A focal length ranges from 1mm to 4 mm approximately.All the components have high optical transparency(90%)at the wavelength of 1.55 μm to be suitable for optical communication coupled devices.The surface roughness of microlens is measured by an atomic force microscope(AFM-Ⅱ).Micro-lens forming mechanics has been analyzed by surface tension theory..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1639 (2005)
The Preparation of Nanometer Silver Colloid by Photochemical Method and Its Character Study
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The silver colloids were prepared by ultraviolet photochemical method. It was found that the position of the absorption maximum of the silver colloids gradually blue shift with the concentration of the silver nitrate increasing and then the position of the absorption maximum of the silver colloids gradually red shift wThe silver colloids were prepared by ultraviolet photochemical method. It was found that the position of the absorption maximum of the silver colloids gradually blue shift with the concentration of the silver nitrate increasing and then the position of the absorption maximum of the silver colloids gradually red shift with the concentration of the silver nitrate increasing. Also, it was found the position of the silver colloids absorption maximum does not change, but the value of absorption maximum increases with the concentration of trisodium citrate. The TEM image of the silver colloids shows that the scale of the silver particle change from 5 nm to 20 nm..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1643 (2005)
Compensating Nonlinearity of Optical Path Difference of Rotary Fourier Transform Spectrometer with Fitting Interferogram
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Because of rotating reflector or refractor,there is nonlinearity of Optical Path Difference(OPD) in high-speed rotary FT-Spectrometer.Nonlinearity which was studied to direct engineering in this paper is a very important aspect to be considered in designing system. In nonlinear OPD system,interferogram is sampled lineaBecause of rotating reflector or refractor,there is nonlinearity of Optical Path Difference(OPD) in high-speed rotary FT-Spectrometer.Nonlinearity which was studied to direct engineering in this paper is a very important aspect to be considered in designing system. In nonlinear OPD system,interferogram is sampled linearly,which brings interferogram phase and period error.The case corresponds to the interferogram without those errors sampled nonlinearly.Interferogram without phase and period errors can be reconstructed with those interferogram data sampled in unequal intervals through fitting polynomial.Then the reconstructed interferogram is sampled in equal intervals.Those data are used to reconstruct spectrum without noise caused by OPD nonlinearity.Computer simulation shows this method is effective,and fits interferogram with quartic polynomial well.The method is also effective in other nonlinear OPD systems..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1647 (2005)
Study on frequency upconverion of multiwalled carbon nanotubes
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The absorption and photoluminescence spectrum of MWNTs have been measured. The optical frequency upconversion has been observed from MWNTs. The photoluminescence spectrum,which was observedonexcitationat1064nm,consistedofabroadstructuredband,peakingatapproximately780nm.Van Hove Singularities (VHS) in the density of staThe absorption and photoluminescence spectrum of MWNTs have been measured. The optical frequency upconversion has been observed from MWNTs. The photoluminescence spectrum,which was observedonexcitationat1064nm,consistedofabroadstructuredband,peakingatapproximately780nm.Van Hove Singularities (VHS) in the density of states of multiwalled carbon nanotubes have been discoveredfromabsorptionspectrum.Thepeaks,correspondingtoVHS,locatedat685nm,719nm,894nm.The mechanism describing the underlying processes shows that the excitation involves double-photon absorption followed by non-radiative vibrational decay to the VHS states. Subsequently, the luminescence is produced by radiative transition..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1651 (2005)
Synthesis and Spectra Properties of Rare-earth (Sm3+) Organic Complexes
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Three rare earth(Sm 3+) binary chelates with Hexafluoroacetyl acetone(HFA), thenoyltrifluoroacetylacetone(HTTA)and dibenzoylmethide(DBM) as the ligands were synthesized, respectively. The absorption and fluorescence properties of the ligands and their chelates Sm(TTA)~~3 , Sm (HFA)~~3, Sm(DBM)~~3 were investigated. ForThree rare earth(Sm 3+) binary chelates with Hexafluoroacetyl acetone(HFA), thenoyltrifluoroacetylacetone(HTTA)and dibenzoylmethide(DBM) as the ligands were synthesized, respectively. The absorption and fluorescence properties of the ligands and their chelates Sm(TTA)_3 , Sm (HFA)_3, Sm(DBM)_3 were investigated. For both Sm(HFA)_3 and Sm(TTA)_3, there existed a strong fluorescence peak in 645 nm, which ascribed to the transition of 4G_ 5/2→6H_ 9/2 of Sm 3+. However, the plentiful C-H grouped on the rare earth complex Sm(DBM)_3 presumably was quenched the luminescence by nonradiative dissipation of energy which brought from the high energy C-H vibrations, resulting in no peaks over all inspected wavelengths. It was also found the fluorescence intensity of complex Sm(TTA)_3 was the topmost, which was firstly attributed to two substituents on the ligand , -CF_3 and s. Secondly, among three complexes, the match of Sm 3+ and HTTA was the best and lead to stronger fluorescence intensity of complex Sm(TTA)_3, accord.
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1654 (2005)
Aberration Properties of the Decentered and Tilted Optical Systems
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The aberration properties of optical systems with large tilted and decentered plane-parallel refractive plate system and wedge system were analyzed with a new primary aberration analysis method for non-coaxial optical systems,i.e.vector aberration theory. Comparing with an exact ray trace using a computer design prograThe aberration properties of optical systems with large tilted and decentered plane-parallel refractive plate system and wedge system were analyzed with a new primary aberration analysis method for non-coaxial optical systems,i.e.vector aberration theory. Comparing with an exact ray trace using a computer design program for non-coaxial optical system with the theoretical third-order predictions,it is shown that the results are in good agreement.So it proves that the vector aberration theory is good for analyzing and designing optical systems with large tilted and decentered components..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1658 (2005)
Numerical Analysis of Double Pass Rapid Scanning Optical Delay Line in Optical Coherence Tomography
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Double pass Rapid Scanning Optical Delay Line (RSOD), as an axial scanning method widely which is used in Optical Coherence Tomography (OCT), is one of key technologies in developing OCT. This thesis was deeply analyzed beam transmission and beam distribution in RSOD under the condition of coupling optimization using mDouble pass Rapid Scanning Optical Delay Line (RSOD), as an axial scanning method widely which is used in Optical Coherence Tomography (OCT), is one of key technologies in developing OCT. This thesis was deeply analyzed beam transmission and beam distribution in RSOD under the condition of coupling optimization using matlab, thus increased theoretic arguments for RSOD design, elements choice and system adjustment. The two defocus distances Δf=1 μm and Δf=578 μm were got as theoretic coupling optimization, but concerning the practical adjustment, the defocus distance Δf=1 μm was better.So Δf=1 μm was the coupling optimization of RSOD..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1663 (2005)
Eye Model Based on Wavefront Aberration Measured Subjectively
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The wavefront aberration of the human′s eye, which was described by Zernike polynomials coefficients,was measured by the subjective Ray-tracing wavefront sensor. Then the Gullstrand-Le Grand eye model was chosen as the original configuration. The medical corneal topography was used to measure the corneal anterior and pThe wavefront aberration of the human′s eye, which was described by Zernike polynomials coefficients,was measured by the subjective Ray-tracing wavefront sensor. Then the Gullstrand-Le Grand eye model was chosen as the original configuration. The medical corneal topography was used to measure the corneal anterior and posterior surfaces and high order aspheric function was chosen to fit the corneal surfaces. The depths among each components of the eye were measured with ultrasonic technology. And taking the Zernike coefficients as the merit function in the optical design software Zemax, we optimize the lens′s shape which was defined with the Zernike Fringe sag surface. At last, the individual eye model was established. The wavefront aberration calculated from the model was exactly equal to the data measured with ray-tracing technology..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1666 (2005)
The Diffraction Integral and Fractional Fourier Transform of Misaligned Single Spherical Refracting System
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According to geometric feature of spherical surface,the misalignment characteristics of single spherical refracting system when the refracting surface was tilted and decentered were analyzed.From the principle of ordered multiplication of matrix of on-axis element and matrix of decentered element,the strict matrix whicAccording to geometric feature of spherical surface,the misalignment characteristics of single spherical refracting system when the refracting surface was tilted and decentered were analyzed.From the principle of ordered multiplication of matrix of on-axis element and matrix of decentered element,the strict matrix which described the misaligned single spherical refracting system were presented.With the relation between system diffraction integral and the misaligned matrix element,the diffraction integral of the misaligned system was derived.Based on the structure parameters of fractional Fourier transform of single spherical refracting system,the misaligned fractional Fourier transform was also obtained.The result can be used in numerical calculation and simulation of diffraction and fractional Fourier transform of input complex amplitude of misaligned single spherical refracting system..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1670 (2005)
Jones Matrix Based Synthesis for FIR Optical Filter Uusing Birefringent Crystals
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FIR optical filter using birefringent crystals consists of N cascaded crystal waveplates with the same thickness between an input and an output polarizer.The variables determined by synthesis procedure are the angles of the optic axes of the crystal waveplates and the angle of the output polarizer.A Jones matrix based FIR optical filter using birefringent crystals consists of N cascaded crystal waveplates with the same thickness between an input and an output polarizer.The variables determined by synthesis procedure are the angles of the optic axes of the crystal waveplates and the angle of the output polarizer.A Jones matrix based step-down iteration synthesis procedure for filter of this kind is proposed.Jones matrix describing such filters is the product of Jones matrixs of waveplates and polarizers used in filter.A simple step-down iteration relation and the orthogonal frequency response correspond to frequency response of filter is determined by this condition.The experimental result agrees with that provided by the reference and shows that the synthesis procedure is simple..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1673 (2005)
A Novel Optical Mode Converter
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A novel unitary optical mode converter was proposed, which can transform Hermite-Gaussian beams with the same Rayleigh range and waist position into Laguerre-Gaussian beams. Being unitary and having only two reflecting faces, the mode converter was easily adjusted and had very small reflecting loss. In view of the HertA novel unitary optical mode converter was proposed, which can transform Hermite-Gaussian beams with the same Rayleigh range and waist position into Laguerre-Gaussian beams. Being unitary and having only two reflecting faces, the mode converter was easily adjusted and had very small reflecting loss. In view of the Hertmite-Gaussian beams with different Rayleigh range and waist position, a waist adjuster was proposed. Such Hertmite-Gaussian beams can also be transformed into Laguerre-Gaussian beams by combining the adjuster and the converter..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1677 (2005)
Precision Analysis of Nonuniformity Correction of IRFPA
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Some general methods for nonuniformity correction of infrared focal plane array (IRFPA) were discussed in the article. Multi-point linear algorithm (MPLA) based on black body was used to correct some images of IRFPA with size of 128×128 and the results were rather good. Method for the selection and determining of Some general methods for nonuniformity correction of infrared focal plane array (IRFPA) were discussed in the article. Multi-point linear algorithm (MPLA) based on black body was used to correct some images of IRFPA with size of 128×128 and the results were rather good. Method for the selection and determining of the number of the used points were analyzed with knowledge of the response curves of the detector because the performance of MPLA was related to these two factors. And the influence of them was also researched practically, which showed the perfect reconciliation with former analysis..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1681 (2005)
Latest Development of Hybrid Uncooled Pyroelectric IR FPA
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128×128 element Hybrid Uncooled Pyroelectric IR FPA,which was developed by Kunming Institute of Physics,was introduced in this paper.First,the national and oversea development of Hybrid Uncooled Pyroelectric IR FPA and hybrid structure was used in the FPA were presented,then the key factor that effected on the FPA128×128 element Hybrid Uncooled Pyroelectric IR FPA,which was developed by Kunming Institute of Physics,was introduced in this paper.First,the national and oversea development of Hybrid Uncooled Pyroelectric IR FPA and hybrid structure was used in the FPA were presented,then the key factor that effected on the FPA′s performance was analyzed.Not only were the material′s electrics and physical characteristic that were applied in the FPA,but also heat isolation structure and ROIC technology were discussed.Some IR explicit picture getting from the IR FPA was given.At last,experimentation result and some methods that improving performance was applied in the future were discussed and analyzed..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1685 (2005)
The Research of Fiber Optic Evanescent Wave Biosensor
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A fiber-optic evanescent wave biosenor has been developed which transmitted excitation laser beam and fluorescence signal through fiber bundle.Based on the theory of evanescent wave and mode matching in probe,the geometric figure of probe was designed,and five group probes were made.According to needs,some of them withA fiber-optic evanescent wave biosenor has been developed which transmitted excitation laser beam and fluorescence signal through fiber bundle.Based on the theory of evanescent wave and mode matching in probe,the geometric figure of probe was designed,and five group probes were made.According to needs,some of them with Cy5 were also labeled.Then,probes were put in air and water,and the signal of the fiber-optic biosensor was examined respectively.Comparing the different results between labeled probe and unlabeled one,the existing of fluorescence signal in fiber-optic biosensor detected signal and the feasibility of the designed fiber-optic biosensor were confirmed and proved respectively..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1688 (2005)
The Breeding of High-Yield Pectinase Producing Bacteria Using He-Ne Laser Irradiation on the Cell and Protoplasts
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A mutant strain ZH-g was screened by He-Ne laser mutagenesis on the cells.Its pectinase activity was in 1.3 fold of the original one,reaching 301 μ/mL.On the basis of this,using He-Ne laser irradiating on the protoplasts of ZH-g,the mutant strain ZH-gA with high yield of pectinase was obtained.It accumulated pectinase A mutant strain ZH-g was screened by He-Ne laser mutagenesis on the cells.Its pectinase activity was in 1.3 fold of the original one,reaching 301 μ/mL.On the basis of this,using He-Ne laser irradiating on the protoplasts of ZH-g,the mutant strain ZH-gA with high yield of pectinase was obtained.It accumulated pectinase activity up to 357 μ/mL which was 18% higher than that of the parent strain.This strain can produce pectinase efficiently under both aerobic and static cultivation.The enzyme activity is stable after several times of batch..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1693 (2005)
Ultra-Long Period Fiber Gratings Written by High-Frequency CO2 Laser Pulses
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Novel ultra-long period fiber gratings (ULPFGs) with periods of up to several millimeters, which were written by the high-frequency CO~~2 laser pulses,were reported.The refractive index change occured mainly within the cladding area of the fiber and had an unsymmetrical distribution on the cross-section of the ULPFG.ThNovel ultra-long period fiber gratings (ULPFGs) with periods of up to several millimeters, which were written by the high-frequency CO_2 laser pulses,were reported.The refractive index change occured mainly within the cladding area of the fiber and had an unsymmetrical distribution on the cross-section of the ULPFG.The resonant loss peaks of the ULPFG were generated from the coupling of the forward propagating core mode to the cladding modes of fundamental and harmonic orders.Such a ULPFG can be used to measure multi-parameters simultaneously as these resonant loss peaks have different sensitivities to temperature,strain,bending and torsion,et al.The temperature and strain characteristics of the ULPFGs with 3 mm period were investigated by experiment.Meanwhile,several new approaches of the potential applications of the ULPFG were proposed..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1697 (2005)
Application of Dispersion and Dispersion Slope Compensation Based on Optimization of Binary Phase-Sampled Fiber Bragg Gratings
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The binary phase-sampled fiber Bragg grating was optimized based on the particle swarm optimization method.Through the method,the dispersion and dispersion slope compensation technology were proposed by the binary phase-sampled fiber Bragg gratings. The bandwidth of each channel could be adjusted by the chirped period The binary phase-sampled fiber Bragg grating was optimized based on the particle swarm optimization method.Through the method,the dispersion and dispersion slope compensation technology were proposed by the binary phase-sampled fiber Bragg gratings. The bandwidth of each channel could be adjusted by the chirped period of the grating, and the total dispersion of each channel was dependent on the length of the seed grating. Finally the dispersion slope could be altered by adjusting the sampled function. So this technology is very attractive in design the multi-channel dispersion compensation devices for wavelength division multiplex system..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1701 (2005)
QoS Policies for Core Nodes in Optical Burst Switching Networks
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A new mechanism of feedback acknowledge is proposed for avoiding loss of data bursts.It is the principle that if failed to establishing end-to-end wavelength path during setting up,the fault core node will send back a acknowledge information (NACK) to the original edge node,once the original edge node receives NACK infA new mechanism of feedback acknowledge is proposed for avoiding loss of data bursts.It is the principle that if failed to establishing end-to-end wavelength path during setting up,the fault core node will send back a acknowledge information (NACK) to the original edge node,once the original edge node receives NACK information before the data burst to be scheduled has not be output,the plan of scheduling the data burst for output will be cancelled and that data burst will be buffered again to be ready for scheduling next time.In such way,a more reliable wavelength path and a less loss may be provided for data burst..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1706 (2005)
The Data Extracting System of High-Speed Particle Field Measurement Using In-line Fraunhofer Holography
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In this paper, the data extracting method of high speed particle field ejected from material surface under explosion using in-line Fraunhofer holography was introduced. During the reconstruction,the image of the 3D particle field reconstructed from hologram was divided into many small slices and then these slices was aIn this paper, the data extracting method of high speed particle field ejected from material surface under explosion using in-line Fraunhofer holography was introduced. During the reconstruction,the image of the 3D particle field reconstructed from hologram was divided into many small slices and then these slices was acquired by a CCD camera. During the data processing, first of all whether in the whole or in some parts of the image extracting larger particles using edge detection based on the edge of particles in the image was determined, then the image was divided into several small areas and these small areas was segmented using a threshold. On the last process of correcting the result, the particles that was larger or smaller than a standard was confirmed as noise and that was repeatedly disposed were got rid of. Using this method, the space-distributing and the statistic of the particles were achieved..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1710 (2005)
Study on the Photobleaching of Different Xanthenes Dyes and Holographic Properties
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Photobleaching of five different xanthenes dyes Erythrosin B (ErB), Eosin Y (EY), Rose Bengal (RsB), Rodamine B (RoB) and Fluorescein (F) were studied. The bleaching kinetics of xanthenes dyes followed the order ErB>EY>RsB>RoB>F in presence of an electron donor triethanolamine (TEA). The influence of exposePhotobleaching of five different xanthenes dyes Erythrosin B (ErB), Eosin Y (EY), Rose Bengal (RsB), Rodamine B (RoB) and Fluorescein (F) were studied. The bleaching kinetics of xanthenes dyes followed the order ErB>EY>RsB>RoB>F in presence of an electron donor triethanolamine (TEA). The influence of expose intensity and dye′s concentration on the photobleaching process of xanthenes dyes and the holographic recording properties of the five dyes were presented..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1714 (2005)
Tomographic Reconstruction from Fewer Views by Local Basis Function Approach
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The reconstructions based on 6 kinds of basis functions were compared by computer simulation. The result indicates that the reconstruction based on differentiable basis function is better than that based on non-differentiable basis function and the reconstructions based on different differentiable basis function is appThe reconstructions based on 6 kinds of basis functions were compared by computer simulation. The result indicates that the reconstruction based on differentiable basis function is better than that based on non-differentiable basis function and the reconstructions based on different differentiable basis function is approximately the same. The computation of projection matrix is mostly considered for the choice of basis functions..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1719 (2005)
An Improved Joint Scheme for Image Denoising
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On the basis of the combined method presented in Reference[7],an improvement was implemented by exploiting the characteristics of both wavelet thresholding denoising and spatial Wiener filtering.After BayesShrink thresholding denoising in wavelet domain to obtain a pre-denoised image,the noise variance was estimated foOn the basis of the combined method presented in Reference[7],an improvement was implemented by exploiting the characteristics of both wavelet thresholding denoising and spatial Wiener filtering.After BayesShrink thresholding denoising in wavelet domain to obtain a pre-denoised image,the noise variance was estimated for the following Lee filtering.The optimal noise variance estimation for Lee filter was given by numerical computation.Experiment results show the improvement of the proposed approach in terms of MSE,signal-to-noise ratio (SNR),as well as adaptability to different images..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1748 (2005)
Anomaly Detection in Hyperspectral Imagery Based on Feature Fusion of Band Subsets
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Detecting camouflaged targets in an unknown environment presents a great challenge in hyperspectral image analysis since the prior knowledge about targets and background is not available.A nomaly detection method for hyperspectral imagery was proposed for this problem. Features were extracted from subband sets of hyperDetecting camouflaged targets in an unknown environment presents a great challenge in hyperspectral image analysis since the prior knowledge about targets and background is not available.A nomaly detection method for hyperspectral imagery was proposed for this problem. Features were extracted from subband sets of hyperspectral imagery,then fusion algorithm for detection was implemented by D-S evidence reasoning while basic belief assignment function was constructed involving high-order moments of features.Theoretical analysis and results of experiment verify the effectiveness of the algorithm..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1752 (2005)
Prediction Algorithm for Laser Chaotic Based on Stationary Wavelet Transform and Reconstructed Phase Space
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A new algorithms for laser chaotic time series prediction was presented. The origin time series was decomposed as the measurement coefficients and wavelet coefficients based on the discrete stationary wavelet transform algorithms.The phase space of these coefficients was reconstructed by the theory of time delays. BaseA new algorithms for laser chaotic time series prediction was presented. The origin time series was decomposed as the measurement coefficients and wavelet coefficients based on the discrete stationary wavelet transform algorithms.The phase space of these coefficients was reconstructed by the theory of time delays. Based on the stability and the fractal of the chaotic attractor, the coefficients were predicted in their phase space. Finally the prediction of the coefficients were acquired by the inverse discrete stationary wavelet transform . The proposed algorithm was a better candidate for long range prediction.The simulation results prove the similarity of dynamic invariants between the origin and generated time series.And it shows that the proposed method can capture the dynamics of the nonlinear systems series effectively..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1756 (2005)
Physical Optics
Diffractive Optical Element Designed by YG Algorithm for Beam Shaping in Fractional Fourier Transform Domain
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For the diffractive optical element (DOE) realizing beam shaping in the fractional Fourier transform domain,the transform matrix calculated by the discrete sampling points was compared with that calculated by the Fresnel integral,and the discretization error of the intensity distribution on the output plane was qualitaFor the diffractive optical element (DOE) realizing beam shaping in the fractional Fourier transform domain,the transform matrix calculated by the discrete sampling points was compared with that calculated by the Fresnel integral,and the discretization error of the intensity distribution on the output plane was qualitatively obtained.Simulated results show this discretization error cannot be neglected.Therefore the Fresnel integral should be used to obtain the true intensity distribution on the output plane.Because the transform matrix calculated with the Fresnel integral was non-unitary,YG algorithm was used to design the DOE realizing beam shaping in the fractional Fourier transform domain in this paper..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1724 (2005)
Measurement Principle and Method for Liquid Crystal's Rotational Viscosity Coefficient
Rotational viscosity is one of important liquid crystal′s physical properties for display and telecommunication industries.The measurement method and principle of the temperature dependence of rotational viscosity coefficient of nematic liquid crystal were investigated on a personal computer-based optical system develoRotational viscosity is one of important liquid crystal′s physical properties for display and telecommunication industries.The measurement method and principle of the temperature dependence of rotational viscosity coefficient of nematic liquid crystal were investigated on a personal computer-based optical system developed by us.Rotational viscosity coefficient was caculated from the phase decay time tested on the optical system.The data of the temperature dependence of rotational viscosity coefficient of a typical LC material―a Merck nematic E7 mixture were given,and experimental results agree with the theory well,which verifies the correction of the principle.The method is simple and automatic..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1728 (2005)
Propagation of nonparaxial Bessel-Gaussian beams in free space
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Stating from the Rayleigh-Sommerfeld diffraction integral,the closed-form propagation expression for nonparaxial Bessel-Gaussian beams of any order in free space was derived.The propagation equations of nonparaxial Bessel and Gaussian beams were deduced as special case of our general result.Physical analysis and numeriStating from the Rayleigh-Sommerfeld diffraction integral,the closed-form propagation expression for nonparaxial Bessel-Gaussian beams of any order in free space was derived.The propagation equations of nonparaxial Bessel and Gaussian beams were deduced as special case of our general result.Physical analysis and numerical calculations show that,if the transversal scale of Gaussian and Bessel parts are comparable with or less than the wavelength,the nonparaxial approach should be used..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1732 (2005)
Effects of Multilayer Structure of Ag-SiO2 Films on the Photonic Band Gap
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The one-dimensional photonic crystals of Ag/SiO2system are studied to investigate the photonic band gaps (PBG). The samples were prepared by the ultra-high vacuum electron beam evaporation. The clear band gaps were observed. Satisfactory agreement between experimental and calculated results was obtained without fittingThe one-dimensional photonic crystals of Ag/SiO2system are studied to investigate the photonic band gaps (PBG). The samples were prepared by the ultra-high vacuum electron beam evaporation. The clear band gaps were observed. Satisfactory agreement between experimental and calculated results was obtained without fitting. The thickness of SiO2 film has influence on the photonic band gap, as well as it awfully affects the transmittance of Ag. More layers can get clearer PBG..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1736 (2005)
Quantum Optics
Third-order Nonlinear Optical Susceotibility in a Cylindrical Quantum Dot
Under the effective mass approximation, the analytic expression for the third-harmonic generation (THG) in cylindrical quantum dots was derived by using the density matrix method. The numerical calculations were performed on a cylindrical GaAs/Al~~βGa~~ 1-βAs quantum dot with different incident photon energy, polarizatUnder the effective mass approximation, the analytic expression for the third-harmonic generation (THG) in cylindrical quantum dots was derived by using the density matrix method. The numerical calculations were performed on a cylindrical GaAs/Al_βGa_ 1-βAs quantum dot with different incident photon energy, polarizations, and under various dot dimensions and Al concentrations. It is found that the THG is more than two orders of magnitude larger than that of bulk GaAs under appropriate conditions..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1740 (2005)
Anti-bunching Effects of the Photon-added Squeezed Vacuum States
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The anti-bunching properties of photons in the photon-added squeezed vacuum states were discussed in this paper.The results show that both Boson inverse operators and Boson operators acting on the usual squeezed vacuum states appear the anti-bunching effects. However,the effects due to the actions of Boson inverse operThe anti-bunching properties of photons in the photon-added squeezed vacuum states were discussed in this paper.The results show that both Boson inverse operators and Boson operators acting on the usual squeezed vacuum states appear the anti-bunching effects. However,the effects due to the actions of Boson inverse operators are related to the squeeze parameter of the squeezed vacuum states and the number k of the added photons.Those due to the actions of Boson operators have the same squeeze parameter range but have no relatonship with the number k of the added photons..
Acta Photonica Sinica
- Publication Date: Nov. 30, 2005
- Vol. 34, Issue 11, 1745 (2005)
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