Journals >Acta Photonica Sinica
Contents
2005
Volume: 34 Issue 5
41 Article(s)
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Research Article
Dependence of Attosecond Pulses on The Chirp of The Excitation Pulse
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
With soft-core potential model and single electron approximation, the dependence of attosecond pulses on the chirp of the excitation pulse is theoretically investigated by solving 1D time-dependent Schr’dinger equation. The intensity and duration of the attosecond pulses are respectively analyzed. The results show thatWith soft-core potential model and single electron approximation, the dependence of attosecond pulses on the chirp of the excitation pulse is theoretically investigated by solving 1D time-dependent Schr’dinger equation. The intensity and duration of the attosecond pulses are respectively analyzed. The results show that, instead of producing single attosecond pulse as the unchirped pulse, both the positively and negatively chirped laser pulses will produce attosecond pulse trains. With the increase of the positive chirp of the driving laser pulse , the duration of the attosecond pulse will increase greatly, while the negatively chirped pulse′s effect is little, and some negative chirp can even generate shorter attosecond pulse than that of the zero chirp case..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 641 (2005)
Experimental Study on Large-mode-area Yb3+-doped Double-clad Fiber Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A large-mode-area Yb 3+ -doped double clad fiber laser operating in CW pump and pulsed pump regime, respectively, is described. With CW pump, a 4.6 W quasi-continuous output operating in the 1.09 μm is obtained, when the pump power is 10.4 W. With pulsed pump, the laser generates nanosecond pulses with a stable repetitA large-mode-area Yb 3+ -doped double clad fiber laser operating in CW pump and pulsed pump regime, respectively, is described. With CW pump, a 4.6 W quasi-continuous output operating in the 1.09 μm is obtained, when the pump power is 10.4 W. With pulsed pump, the laser generates nanosecond pulses with a stable repetition rate of 5 kHz. A single-pulse energy of as much as 0.26 mJ with a peak power of 5.3 kW is obtained..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 644 (2005)
LD Pumped Yb:YAG Mode-locked Laser with SESAM
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the 940 nm LD pumped Yb∶YAG laser, the stable mode-locked trains wavelength at 1030 nm and 1050 nm is obtained by use of two pieces SESAM.The spectrum FWHM are 1nm and 2 nm. The repetition rates are 190.24 MHz and 178.6 MHz. The average power of output is 80 mW and 60 mW when the pump power is 4W.In the 940 nm LD pumped Yb∶YAG laser, the stable mode-locked trains wavelength at 1030 nm and 1050 nm is obtained by use of two pieces SESAM.The spectrum FWHM are 1nm and 2 nm. The repetition rates are 190.24 MHz and 178.6 MHz. The average power of output is 80 mW and 60 mW when the pump power is 4W..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 648 (2005)
Theoretic Analysis of Coupled Output from Ring Laser with Total Reflection Prism
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A way is studied to obtain output laser from ring laser with total reflection prisms by prism coupler. The expressions of the reflection coefficient and the transmission coefficient of the prism coupler constructed by cuniform clearance are deduced in theory, furthermore the theoretical curve of the reflectivity and thA way is studied to obtain output laser from ring laser with total reflection prisms by prism coupler. The expressions of the reflection coefficient and the transmission coefficient of the prism coupler constructed by cuniform clearance are deduced in theory, furthermore the theoretical curve of the reflectivity and the transmittivity VS the height of the cuniform clearance showed. Problems ,such as selection of the corresponding stuff, selection of the surge ponderance in the cavity and the influence of the minishing prism couplers on the mode of the ring laser cavity are discussed. The study is considerably important for the laser gyros consist of total prisms in practical application as laser gyro and laser angle speed sensor..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 652 (2005)
Cladding Pumped Erbium-ytterbium Co-doped Double Clad Fiber Ring Laser Operating in L-band
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A cladding pumped Er/Yb co-doped double clad fiber ring laser operating in L-band is demonstrated. A 9-m-long Er 3+ /Yb 3+ co-doped fiber (EYDF) is used as the gain medium, and six diode lasers are used to cladding pump EYDF, by utilizing amplified spontaneous emission as a secondary pump source, the laser can operate A cladding pumped Er/Yb co-doped double clad fiber ring laser operating in L-band is demonstrated. A 9-m-long Er 3+ /Yb 3+ co-doped fiber (EYDF) is used as the gain medium, and six diode lasers are used to cladding pump EYDF, by utilizing amplified spontaneous emission as a secondary pump source, the laser can operate in L-bandstably.Whenthepumpingpoweris3594.5mW,thepumppowerofenteringfiberismeasuredtobe2731.8mW and the maximum output power obtained is 518.4 mW, the slope efficiency is 19%. The laser output wavelength is 1613.94 nm, the 3 dB band width is 0.15 nm, and the side mode suppression ratio is about 50 dB..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 656 (2005)
Long-period Fiber Gratings Fabricated by CW CO2 Laser Pulses
[in Chinese], [in Chinese], and [in Chinese]
Long-period fiber gratings (LPFG) are fabricated by using CW CO_2 laser pulses, and transmission spectra are measured at different grating lengths. The coupling strength shows periodical variation versus the grating lengths.This conclusion is in agreement with the coupled mode theory.Long-period fiber gratings (LPFG) are fabricated by using CW CO_2 laser pulses, and transmission spectra are measured at different grating lengths. The coupling strength shows periodical variation versus the grating lengths.This conclusion is in agreement with the coupled mode theory..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 659 (2005)
Performance Analysis and Design of Quasi-collinear Acousto-optic Mode Converter
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The design of a SiO2 film-loaded Ti: LiNbO3 integrated acousto-optic tunable filter is reported. The configuration, in which an angular offset between the acoustic and optical waveguides is introduced, offers a good performance of suppressing sidelobes. With the mode analysis of the acoustic wave guide and the theory oThe design of a SiO2 film-loaded Ti: LiNbO3 integrated acousto-optic tunable filter is reported. The configuration, in which an angular offset between the acoustic and optical waveguides is introduced, offers a good performance of suppressing sidelobes. With the mode analysis of the acoustic wave guide and the theory of coupling mode the limit of the width, weighted coupling coefficient and the characteristics of the conversion of acousto-optic modes are obtained. Considered the compromise between the sidelobes suppression and filtering bandwidth, the theoretical results are gained that the sidelobes level is -16.8 dB and the theoretical values of bandwidths of -3 dB and -10 dB is 1.37 nm and 2.31 nm..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 662 (2005)
The Analysis of Focal Spot of Geodesic Lenses
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Utilization of geometric optical characters of geodesic lenses, the equivalent light trail and phase transfer function are given. Simultaneously the distributing model is obtained. The focal spot intensity distribution of theory corresponds with the experiments.Utilization of geometric optical characters of geodesic lenses, the equivalent light trail and phase transfer function are given. Simultaneously the distributing model is obtained. The focal spot intensity distribution of theory corresponds with the experiments..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 666 (2005)
Analysis of the Single-mode Condition for a Rib SOI Waveguide with a Large Cross Section
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The single mode condition for a rib waveguide based on silicon-on-insulator (SOI) is determined through the eigen mode analysis using a finite difference method. This single mode condition gives the relation between the normalized rib height r and the normalized rib width t. A comparison is made between the present resThe single mode condition for a rib waveguide based on silicon-on-insulator (SOI) is determined through the eigen mode analysis using a finite difference method. This single mode condition gives the relation between the normalized rib height r and the normalized rib width t. A comparison is made between the present result obtained with a FDM and previous analytical formulas for the single mode condition. Simulation results show that the value for the constant in the previous analytical formulas should be chosen as 0.3 when r >0.5. The present single mode condition is also extended to the range of r<0.5 (which is not considered before)..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 669 (2005)
Study on Energy Transfer from Carotenoid Moleculars to Reaction Centre in PhotosystemⅡdimer
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
To understanding the energy transfer from carotenoids molecular to reaction centre in PSII, PSII particle complex purified from spinach was investigated with ultrafast fluorescence spectroscopy in the case of selective excited carotenoid molecular with 473 nm, 481nm and 507 nm at 77 K. The data were analyzed by fluoresTo understanding the energy transfer from carotenoids molecular to reaction centre in PSII, PSII particle complex purified from spinach was investigated with ultrafast fluorescence spectroscopy in the case of selective excited carotenoid molecular with 473 nm, 481nm and 507 nm at 77 K. The data were analyzed by fluorescence decay time-fitting, and were compared with data of core complex got at the same condition. Three groups of time components about energy transfer of carotenoids were obtained: 16.6ps, 130~183 ps, 217~249 ps. The shortest lifetime component of 16.6 ps was the process of energy transfer from Car 473 molecular to Chl 639 in LHCII. The 130~183 ps were lifetime associated with the process of β-car molecular transfer the energy to RC by a series of intermediates and 217~249 ps reflected the process of Car_ 481 in LHCII transfer it′s energy to RC..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 672 (2005)
Influence of the Convergence Angle on Light Transporting in Biological Tissues
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the diffusion theory,a computational model is developed to deal with the problem of light transporting in biological tissues irradiated by arbitrary light source.According to the numerical calculation,the influence of convergence angle on the light field in biological tissues and light field reflected from bioBased on the diffusion theory,a computational model is developed to deal with the problem of light transporting in biological tissues irradiated by arbitrary light source.According to the numerical calculation,the influence of convergence angle on the light field in biological tissues and light field reflected from biological tissues are discussed.Results show that with the increase of the convergence angle,light field in biological tissues and the reflectance enhanced in the beginning,after reaching the peak value,its intensity decrease quickly and the position of its maximum deflects from central position..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 677 (2005)
The Mutagentc Effect on a Strain Producing PHB by Cooperation of UV and He-Ne Laser
[in Chinese], [in Chinese], and [in Chinese]
The strain G-Q7 producing PHB was irradiated respectively by UV, He-Ne laser and both of them to increase PHB production. The results indicated that the coordinative effect of UV and He-Ne laser was better than using them individually. The cells were treated firstly by He-Ne laser for 20 minutes and then by UV for 150 The strain G-Q7 producing PHB was irradiated respectively by UV, He-Ne laser and both of them to increase PHB production. The results indicated that the coordinative effect of UV and He-Ne laser was better than using them individually. The cells were treated firstly by He-Ne laser for 20 minutes and then by UV for 150 seconds, which resulted in a final cell concentration of 11.5 g/L, PHB content of 65%. The mutant had better hereditary stability. The two PHB polymers obtained from the strains G-Q7 and the mutant were analysed by the method of DSC and NMR, the conclusion appears that the mutagenic effect makes some certain enzyme of metabolism change..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 682 (2005)
Researching on the Experiment of Fiber Bragg Grating Hydrophone
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The FBG being used as the basic sensor unit, a hydrophone sensor has been designed and manufactured. Its principle and relevant experimental result are introduced. By using the matched fiber grating demodulation technique, dynamic signal measurement with high sensitivity is realized. The frequency range of the FBG-baseThe FBG being used as the basic sensor unit, a hydrophone sensor has been designed and manufactured. Its principle and relevant experimental result are introduced. By using the matched fiber grating demodulation technique, dynamic signal measurement with high sensitivity is realized. The frequency range of the FBG-based hydrophone is 10~3 kHz with a dynamic range of 60 dB. Due to the characters of FBG itself, the measure of multiple-points underwater signal can be realized conveniently by using WDM and TDM techniques..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 686 (2005)
Effect of Pumping Light Linewidth on Fiber Raman Amplifier
[in Chinese], [in Chinese], and [in Chinese]
The effect of pumping light linewidth on fiber Raman amplifier used in density wavelength division multiplexed (DWDM) system is analyzed by applying SRS coupling wave theory.It is pointed out that the pumping efficiency will be reduced if the wide-spectrum pumping light is used.The variation curves of pumping light linThe effect of pumping light linewidth on fiber Raman amplifier used in density wavelength division multiplexed (DWDM) system is analyzed by applying SRS coupling wave theory.It is pointed out that the pumping efficiency will be reduced if the wide-spectrum pumping light is used.The variation curves of pumping light linewidth and power versus pumping efficiency are given.A conclusion is presented that lower pumping efficiency will be obtained with larger pumping light power,pumping light linewidth, Raman gain and lesser effective fiber section..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 690 (2005)
Optimization of Coherent Detection Technology for Inter-satellite Tracking
[in Chinese], and [in Chinese]
The mathematical model of coherent detection for inter-satellite tracking is rebuilt under Gaussian approximation. The intermediate frequency current from a detector as a function of a beam mismatched angle is calculated under this model which can get a smaller error compared with the one under plate wave approximationThe mathematical model of coherent detection for inter-satellite tracking is rebuilt under Gaussian approximation. The intermediate frequency current from a detector as a function of a beam mismatched angle is calculated under this model which can get a smaller error compared with the one under plate wave approximation. The expression of the intermediate frequency current is simplified by choosing a right ratio between the detector diameter and the beam diameter, which can improve the calculation efficiency..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 694 (2005)
Study of a Novel Bi-Directional Optical ADD/DROP Multiplexer
[in Chinese], and [in Chinese]
A novel BOADM structure based on fiber gratings and circulators and two experimental structures are proposed. The experimental result shows that the heterohyne crosstalk and homodyne crosstalk of BOADM are -21.4 dB and -32 dB at the channel space of 100 GHz. Moreover, the BOADM , which used unidirectional EDFA is simplA novel BOADM structure based on fiber gratings and circulators and two experimental structures are proposed. The experimental result shows that the heterohyne crosstalk and homodyne crosstalk of BOADM are -21.4 dB and -32 dB at the channel space of 100 GHz. Moreover, the BOADM , which used unidirectional EDFA is simple,cost-effective and easy fit to other equipments, besides, it has self-healing ability..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 697 (2005)
Dispersion-Managed Soliton Interaction in an Optical Time-Division Multiplexed System with Random Dispersion Map
[in Chinese], [in Chinese], and [in Chinese]
Dispersion-managed soliton interaction is investigated in an optical time-division multiplexed system with random dispersion map by the variational approach and the numerical simulation. It is found that the perturbation caused by random dispersion map enhances the interaction between neighboring solitons, and results Dispersion-managed soliton interaction is investigated in an optical time-division multiplexed system with random dispersion map by the variational approach and the numerical simulation. It is found that the perturbation caused by random dispersion map enhances the interaction between neighboring solitons, and results in fluctuations of amplitude and separation which submerge solitons. The interaction distance relates to the standard deviation, the initial relative phases, the pulse width and the relative amplitude..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 701 (2005)
The Method of Increasing the Response Range of DOP Ellipsoid to Polarization Mode Dispersion in 40Gb/s RZ System
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The method is proposed to improve the response range of DOP Ellipsoid to PMD. A conclusion is given that response range of DOP ellipsoid shortest axes to PMD can be greatly increased by using the proper bandwidth filter and selecting proper pulse width laser in RZ code optical fiber communication system. The results alThe method is proposed to improve the response range of DOP Ellipsoid to PMD. A conclusion is given that response range of DOP ellipsoid shortest axes to PMD can be greatly increased by using the proper bandwidth filter and selecting proper pulse width laser in RZ code optical fiber communication system. The results also show that the bandwidth of the filter should be limited above 50 GHz, while pulse width should be limited in 4~10 ps for 40 Gb/s system. Finally, the experiment result shows that the above proposed method are very effective to increase the response range of DOP ellipsoid on PMD in 40 Gb/s system..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 706 (2005)
Three Half-wave Filter and Analysis of Layer Thickness
[in Chinese], [in Chinese], and [in Chinese]
Tooling factor is one of the most important parameters in optical thin film coating process. Calculation indicates that, while coating three half-wave filter, it is possible to roughly get this factor from the passband center position, factor variation and factor difference of different materials from the shape of measTooling factor is one of the most important parameters in optical thin film coating process. Calculation indicates that, while coating three half-wave filter, it is possible to roughly get this factor from the passband center position, factor variation and factor difference of different materials from the shape of measurement curve. With this method, we have produced several kinds of bandpass fileters..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 710 (2005)
Analysis of Liquid Crystal Tunable Febry-Perot Etalon Filters
[in Chinese], and [in Chinese]
The influence of the reflectance phase shift of the reflector on the peak wavelength in a liquid crystal Febry-Perot etalon (LCFPE) filter is discussed. In the tunable LCFPE filter, the peak wavelength is selected by adjusting the applied external voltage. The peak wavelength shifts due to the wavelength-dependent phasThe influence of the reflectance phase shift of the reflector on the peak wavelength in a liquid crystal Febry-Perot etalon (LCFPE) filter is discussed. In the tunable LCFPE filter, the peak wavelength is selected by adjusting the applied external voltage. The peak wavelength shifts due to the wavelength-dependent phase shift of the reflector. A set of simple formulas which can give quickly the phase shift are derived. The simulation results indicate that the reflective phase shift can not be ignored in the design of a LCFPE filter as it plays an important role in determining the peak wavelength and the applied voltage of the device. Using these formulas, a tunable LCFPE filter in the optical communication C-Band is designed..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 713 (2005)
Micromachining Based Direct-Coupled Variable Optical Attenuator
[in Chinese], [in Chinese], and [in Chinese]
A design of micromachining based direct-coupled variable optical attenuator (VOA) is presented. The device operates by misaligning a fiber-to-fiber coupling through a lateral displacement of one of the fibers mounted on a micro-machined flexure driven electromagnetically. The VOA was fabricated using CNC engraving and A design of micromachining based direct-coupled variable optical attenuator (VOA) is presented. The device operates by misaligning a fiber-to-fiber coupling through a lateral displacement of one of the fibers mounted on a micro-machined flexure driven electromagnetically. The VOA was fabricated using CNC engraving and laser spot welding technologies and features a fast dynamic response (<2.3 ms), great dynamic range (0～65 dB) and wide bandwidth. In order to optimize micro-mechanical structure an FET software package ANSYS was employed and simulation of the device operation is reported in details..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 718 (2005)
Bent Crystal Spectrometer for X-ray Space and Time Resolved Measurements
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In order to measure plasma X-ray produced by laser fusion in the 0.2~0.37 nm range, a focusing bent crystal spectrometer has been designed for measuring the spatial and temporal resolutions. The LiF crystal with a 2d spacing of 0.403 nm was elliptically bent at 700℃ for the dispersive element, the Bragg diffractive angIn order to measure plasma X-ray produced by laser fusion in the 0.2~0.37 nm range, a focusing bent crystal spectrometer has been designed for measuring the spatial and temporal resolutions. The LiF crystal with a 2d spacing of 0.403 nm was elliptically bent at 700℃ for the dispersive element, the Bragg diffractive angles vary from 30 to 67.5 degrees, the bent LiF crystal was fixed on the elliptical stainless-steel substrate with an eccentricity of 0.9586 and a focal distance of 1350 mm. The X-ray spectrum emitted from the planar titanium target was photographed by using the bent crystal spectrometer coupled with the X-ray CCD camera at the XG-2 laser facility, the experimental result shows that the spectral resolution is up to 0.001 nm..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 722 (2005)
Detection of Nanometer Distance between Sample and Fiber Tip of NSOM with DDS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
To detect and control the nanometer distance between the sample and the fiber tip is part of the key technology of NSOM system. Here a pizeo sensor with DDS is discussed. One of the sensor′s electrodes is separated into two like parts, one is for exciting the pizeo to shake and the other is for detecting the shake. TheTo detect and control the nanometer distance between the sample and the fiber tip is part of the key technology of NSOM system. Here a pizeo sensor with DDS is discussed. One of the sensor′s electrodes is separated into two like parts, one is for exciting the pizeo to shake and the other is for detecting the shake. The fiber tip is fixed on the pizeo and the pizeo is driven by a DDS. When the fiber tip is far from the sample surface, an exact resonant frequency of the fiber tip is obtained with the error of 0.006 Hz after frequency scanning, and when the tip is within the near-field of the sample, the resonant frequency of the fiber tip departures the resonant frequency in far-field, and the amplitude of the fiber tip obviously decreases because of the shear force between the fiber tip and the sample, and in this way the near-field distance is detected. The combination of high precision frequency source DDS and the pizeo sensor provides a higher sensitivity and stability of near-field detection..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 726 (2005)
Design of Negative Dispersion Mirrors Used for the Femtosecond-pulse Laser
[in Chinese], [in Chinese], and [in Chinese]
The basic theory of dispersion compensation of the thin film is discussed. The optimized multiplayer mirrors used for a femtosecond mode-locked Ti∶Sapphire laser is reported. The mirrors exhibit high reflectivity (>99.5%) over a wavelength range from 720 to 870 nm, high transmittance (>90%) from 510 to 550 nm andThe basic theory of dispersion compensation of the thin film is discussed. The optimized multiplayer mirrors used for a femtosecond mode-locked Ti∶Sapphire laser is reported. The mirrors exhibit high reflectivity (>99.5%) over a wavelength range from 720 to 870 nm, high transmittance (>90%) from 510 to 550 nm and smooth variation of group delay dispersion from 740 to 850 nm. Most GDD of a 5-mm Ti∶Sapphire crystal can be compensated by seven bounces..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 730 (2005)
Influence of Substrate Bias on the Properties of Hard Carbon Films Prepared by MCECR Sputtering
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The carbon films exhibit a variety of useful properties such as a hardness approaching that of a diamond, transparency,a smooth surface morphology,wear resistance and chemical inertness,and were widely applied in the fields of mechanics,electronics,optics,and magnetic,and so on. Experimental studies to obtain high qualThe carbon films exhibit a variety of useful properties such as a hardness approaching that of a diamond, transparency,a smooth surface morphology,wear resistance and chemical inertness,and were widely applied in the fields of mechanics,electronics,optics,and magnetic,and so on. Experimental studies to obtain high quality hard carbon films were conducted using a Mirror-Confinement-type Electron Cyclotron Resonance (MCECR) plasma sputtering method.The carbon films with 40 nm thickness were deposited on Si by sputtering the carbon target with Ar +.The structure of carbon films was analyzed using the X-ray photoelectron spectropscopy (XPS) and high-resolution transmission electron microscopy (HRTEM),the tribological properties were measured using the Pin-on-Disk tribometer,and the nanohardness was measured using the nanoindenter.The effect of substrate bias on the structure,tribological properties,and nanohardness of carbon film was studied in detail,and the best substrate bias was obtained..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 734 (2005)
Microregion Deformation Measurement of Thin Films Using Array Microindentation Mark Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The measurement of deformation in microregion or on a microcomponent always faces two problems. One is the rigid displacement caused by the unitary motion of the specimen, and the other the rather small deformation in the microregion. Therefore, it is quite necessary to find a suitable way to determine the microregion The measurement of deformation in microregion or on a microcomponent always faces two problems. One is the rigid displacement caused by the unitary motion of the specimen, and the other the rather small deformation in the microregion. Therefore, it is quite necessary to find a suitable way to determine the microregion deformations and mechanical properties. In this paper, the deformation in the vicinity of a microcavity defect on the film surface is measured by the proposed array microindentation mark method. The array microindentation marks are indented using a nanoindentation machine and the microcavity defect is produced by the electrical discharge machining (EDM) technique. Moreover, deformations in the microregion are measured under a digital microscopic system. Further, the microregion deformation extracting method, the feasibility and the measuring performance of the array microindentation mark method are also discussed..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 737 (2005)
Influence of Oxygen Partial Pressure on the Mechanical and Optical Properties of SiO2 Films Prepared by Electron Beam Evaporation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Thin SiO_2 films have been deposited by electron beam evapouration method.The influences of oxygen partial pressure on the mechanical,surface morphology and optical properties were studied.The results show that the residual stress in the SiO_2 films varied from compressive stress to tensile stress with the oxygen partiThin SiO_2 films have been deposited by electron beam evapouration method.The influences of oxygen partial pressure on the mechanical,surface morphology and optical properties were studied.The results show that the residual stress in the SiO_2 films varied from compressive stress to tensile stress with the oxygen partial pressure increase,which may be attributed to the evolution of the microstructure.At the same time,the surface roughness became larger and the refractive index decreased with the increase of the oxygen pressure..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 742 (2005)
Calculation of Optical Parameter of MEH-PPV Film
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
MEH-PPV film is a kind of conjugated polymers synthesized by modified Gilch route. The reflection spectrum of MEH-PPV film was measured by the UV-365 spectrophotometer, which is not exact result of the film because of the reflection of glass substrate. A similar formula annulled the influence of the glass was given, anMEH-PPV film is a kind of conjugated polymers synthesized by modified Gilch route. The reflection spectrum of MEH-PPV film was measured by the UV-365 spectrophotometer, which is not exact result of the film because of the reflection of glass substrate. A similar formula annulled the influence of the glass was given, and in this way modified reflection spectrum was figured. With the data of the modified spectrum and the Kramas-Kronig relation, the refraction index of MEH-PPV as a function of wavelength was given. The reflection spectrum is calculated by the Fresnel formulae and the calculated refraction index data in order to compare the measured result of reflection spectrum with the computed result, in which little errors resulted from the method of calculation and the influence of the glass substrate are shown. In addition, the measured absorption spectrum shows a broad peak from 450 nm to 600 nm approximately corresponding to the peak of the curve of refraction index at 550 nm. From those results the calculated refraction indexes are basically resonable and exact..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 746 (2005)
Nonlinear Correction Technique for Radiography Image
[in Chinese], [in Chinese], and [in Chinese]
Principle of nonlinear correction for radiographic image by optic density vs. path length curve was introduced. By the principle of radiography, the function of the optic density and the path length was monotonous on conditional that the X-ray radiation and the scatter distribution were regular. So the optic density vsPrinciple of nonlinear correction for radiographic image by optic density vs. path length curve was introduced. By the principle of radiography, the function of the optic density and the path length was monotonous on conditional that the X-ray radiation and the scatter distribution were regular. So the optic density vs. path length curve could be used to correct the radiographic image. A background was added on the corrected image when the scatter distribution was non-regular. A radiographic image of triangle object was corrected using this method, and the results confirmed the method..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 750 (2005)
PID Controller Based on BP Neural Networks
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
With the advantage of Neural Network & error control, presented the PID servocontroller model basing on BP Neural Network.The principle was applied to turntable for dynamic-simulation-scan-imaging experiment. The technique avoided the question that establishing the PID preference, minished the effect of dry frictioWith the advantage of Neural Network & error control, presented the PID servocontroller model basing on BP Neural Network.The principle was applied to turntable for dynamic-simulation-scan-imaging experiment. The technique avoided the question that establishing the PID preference, minished the effect of dry friction at laigh velocity. The simulation results show that the model is satisfied at precision and stable results..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 754 (2005)
Design and Fabrication of Anti-reflection Coating for 1.55 μm Polarization-insensitive Semiconductor Optical Amplifiers
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
TiO_2/SiO_2 multiple layers anti-refledtion (AR) coatings for the facets of 1.55 μm polarization insensitive semiconductor optical amplifiers were designed and fabricated. Less than 5×10 -4 reflectivities were obtained for both two layers and four layers AR coatings. An In-Situ monitoring for reflectivity was desiTiO_2/SiO_2 multiple layers anti-refledtion (AR) coatings for the facets of 1.55 μm polarization insensitive semiconductor optical amplifiers were designed and fabricated. Less than 5×10 -4 reflectivities were obtained for both two layers and four layers AR coatings. An In-Situ monitoring for reflectivity was designed and employed during the coating process. The amplifier was fabricated forming ridge waveguide structure with 7° tilted cavity, which showed a less than 0.4 dB ASE ripple, a more than 52 nm bandwidth, excellent polarization insensitivity (less than 0.5 dB) over the entire range of wavelength (1.52~1.58 μm) and a gain of 27 dB at bias current of 200 mA and 1550 nm wavelength..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 758 (2005)
A Novel Calibration Technology in Profilometry
[in Chinese], and [in Chinese]
It is only the relative phase distribution between the tested object and reference plane that is attained after phase demodulation and phase unwrapping in profilometry. However, the objective of 3D shape measurement is to obtain the object′s height distribution .The nonlinear mapping relationship of both phase and heigIt is only the relative phase distribution between the tested object and reference plane that is attained after phase demodulation and phase unwrapping in profilometry. However, the objective of 3D shape measurement is to obtain the object′s height distribution .The nonlinear mapping relationship of both phase and height is analysed and deduced in a general experimental setup. The calibration scheme is designed. When the reference plane is shifted, its corresponding phases have been measured. According to the shifted distance and the phase increment ,the mapping relationship between phase difference and depth of the object can determined by the least square interactive method. Finally, a practical experimental system is calibrated and compared with Hung′s method. The experimental results and theoretical analysis show that the new method is characterized by the high accuracy, easy to handle ,lower the complexity of calibration ..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 761 (2005)
System parameter setting in video OTF test
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
OTF of under test lens was tested with pinhole image processing and analyzing, the influences of sampling frequency on test precision were analyzed, and a calibration method of frequency conversion scale and sampling frequency on image plane was presented. The test results on 50 mm focus standard lens showed that the aOTF of under test lens was tested with pinhole image processing and analyzing, the influences of sampling frequency on test precision were analyzed, and a calibration method of frequency conversion scale and sampling frequency on image plane was presented. The test results on 50 mm focus standard lens showed that the accurately calibration and import of system setting parameter effect on test precision directly, calibration method in this paper are accurate and reliable, and can acquire parameter of effecting on spatial frequency calibration and OTF of lens under test accurately, without knowing subsystem parameter..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 765 (2005)
Electroluminescence Characteristic of ZnO Nanoparticles
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Electroluminescences of ZnO nano-particles are observed under volts d.c. The contrast of EL spectra from some powders that dealt with different surfactant had been studied. The EL intensity of the ZnO powders can be enhanced in the sample deal with ODA and DDA by 8 times and 12 times respectively. The EL intensity of tElectroluminescences of ZnO nano-particles are observed under volts d.c. The contrast of EL spectra from some powders that dealt with different surfactant had been studied. The EL intensity of the ZnO powders can be enhanced in the sample deal with ODA and DDA by 8 times and 12 times respectively. The EL intensity of the ZnO sample dealt with ODA is stronger than that of the ZnO sample dealt with DDA under the same volts d.c. The peak at 406 nm should be most probably related to the defect levels of V_ Zn and the peak at 556 nm is attributed to the V_O..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 769 (2005)
Spectroscopic Properties and Thermal Stability of Er3+/ Yb3+ Co-doped TeO2-Li2O-B2O3-GeO2 Glasses
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Er~(3+)/Yb~(3+) co-doped 70TeO_2-5Li_2O-(25-x)B_2O_3-xGeO_2(x=0,5,10,15,20 mol%) glasses were prepared. The thermal stability of glasses were studied. The absorption spectra,emission spectra and fluorescence lifetime of the 4I_ 13/2 level of Er 3+ ions were measured. The stimulated emission cross-section of 4I_ 13/2 → Er~(3+)/Yb~(3+) co-doped 70TeO_2-5Li_2O-(25-x)B_2O_3-xGeO_2(x=0,5,10,15,20 mol%) glasses were prepared. The thermal stability of glasses were studied. The absorption spectra,emission spectra and fluorescence lifetime of the 4I_ 13/2 level of Er 3+ ions were measured. The stimulated emission cross-section of 4I_ 13/2 → 4I_ 15/2 transition was calculated on the basis of McCumber theory. The results show that with increasing GeO_2 content in the glass composition, the thermal stability, fluorescent intensity and lifetime of the 4I_ 13/2 level of Er 3+ ions increase, while fluorescence full width at half maximum (FWHM) is fixed at about 70 nm. The obtained data suggest that the system of these glasses can be used as a suitable candidate host material for potential broadband optical amplifier..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 773 (2005)
Study on Double-Frequency Properties of In: Nd: LiNbO3 Crystals
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In∶Nd∶LiNbO_3 crystals were grown by Czochralski method with In_2O_3 and Nd_2O_3 as dopants.The optical damage resistance ability of In∶Nd∶LiNbO_3 crystal was investigated by light spot distortion method and the photorefractive threshold of In∶Nd∶LiNbO_3 measured is 1.98×10 4 W/cm 2,two order of magnitude higher tIn∶Nd∶LiNbO_3 crystals were grown by Czochralski method with In_2O_3 and Nd_2O_3 as dopants.The optical damage resistance ability of In∶Nd∶LiNbO_3 crystal was investigated by light spot distortion method and the photorefractive threshold of In∶Nd∶LiNbO_3 measured is 1.98×10 4 W/cm 2,two order of magnitude higher than that of Nd∶LiNbO_3 crystal,1.6×10 2 W/cm 2.The structure of the crystals was measured by ultraviolet-visible absorption spectra.The results show that the absorption edge shifted to the ultraviolet band.The double-frequency property of In∶Nd∶LiNbO_3 crystal was measured.The results indicate that the SHG conversation efficiency of In∶Nd∶LiNbO_3 crystals was twice higher than that of Nd-doped LiNbO_3 crystals and the phase matching temperature was near room temperature..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 778 (2005)
Giant Band Gaps of Rectangle Lattice 2D Photonic Crystal at High Frequency
[in Chinese], and [in Chinese]
The absolute band gap is improved by reducing the symmetry of the photonic crystal, two structures of the rectangle lattice 2D photonic crystal with rectangle dielectric rods is put forward. The modified plane-wave expansion method for calculating quickly the band structure is used to study the absolute band structure The absolute band gap is improved by reducing the symmetry of the photonic crystal, two structures of the rectangle lattice 2D photonic crystal with rectangle dielectric rods is put forward. The modified plane-wave expansion method for calculating quickly the band structure is used to study the absolute band structure at high frequency field, parameters is optimized, when rectangle lattice 2D photonic crystal contains only one set of rectangle dielectric rods, an absolute band gap Δω=0.1265ω_e (where ω_e=2πc/a, a is the lattice constant ,c is light speed) is found at a high frequency field, which mid-frequency ω_ mid = 1.9256ω_e,Δω/ω_ mid =6.6%; when rectangle lattice 2D photonic crystal contains two set of rectangle dielectric rods, a larger absolute band gap Δω=0.203ω_e is also found at a high frequency field, which mid-frequency ω_ mid = 1.8597ω_e, Δω/ω_ mid =10.9%..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 781 (2005)
Study on the Dynamic Holographic Storage Characteristics in C60-doped Nemtic Liquid Crystal
[in Chinese], and [in Chinese]
The holographic grating formation induced by an input pattern in company with a reference wave in a fullerene-doped nematic liquid crystal film were studied experimentally. In experiment we employed a particular method in order to reconstruct the hologram, namely recorded the hologram under low voltage and reconstructeThe holographic grating formation induced by an input pattern in company with a reference wave in a fullerene-doped nematic liquid crystal film were studied experimentally. In experiment we employed a particular method in order to reconstruct the hologram, namely recorded the hologram under low voltage and reconstructed the hologram by high voltage. Evidence concerning the reconstruction of holograms indicates that this photorefractive liquid crystal can, indeed, serve as a hologram-recording medium. Finally, we analyzed the reconstruction mechanism..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 785 (2005)
Quantum Optics
Thermal Entanglement in a Two-level Atom Resonantly Coupled to Single-mode Cavity System
[in Chinese]
The thermal entanglement produced by resonant Jaynes-Cummings model with and without the effect of virtual-photon field is investigated.It is shown that there exists a critical temperature,above which thermal entanglement of atom and field mode vanishes.In the absence of virtual-photon field,the critical temperature inThe thermal entanglement produced by resonant Jaynes-Cummings model with and without the effect of virtual-photon field is investigated.It is shown that there exists a critical temperature,above which thermal entanglement of atom and field mode vanishes.In the absence of virtual-photon field,the critical temperature increases with the increasing of the coupling constant between atom and cavity field.Thermal entangelement can be generated for sufficiently strong coupling under room temperature.In the presence of virtual-photon field,it is also shown that the critical temperature is determined by the processes of real and virtual photon transition.When the process of virtual photon transition is equal to that of real photon transition,no thermal entanglement takes place even if the setup is cooled to below the critical temperature..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 789 (2005)
Dynamics of Cavity Polaritons in a GaAs Quantum-well Semiconductor Microcavity
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
To provide the dynamics of cavity polariton in semiconductor microcavity containing GaAs quantum-well, the dispersions of the three cavity polaritons have been given by the model of three coupled oscillators, meanwhile the linewidths, group velocities and the mass of the three cavity polaritons have been demonstrated. To provide the dynamics of cavity polariton in semiconductor microcavity containing GaAs quantum-well, the dispersions of the three cavity polaritons have been given by the model of three coupled oscillators, meanwhile the linewidths, group velocities and the mass of the three cavity polaritons have been demonstrated. The results indicated that because of the weight occupied by the photon, heavy hole exciton and light hole extiton in the three cavity ploariton the cavity polaritons exhibited different dynamic behaviors..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 793 (2005)
Interference Stability Analysis of Quantum Key Distribution System Based on Single Photon
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In order to study the interference stability in phase coded quantum key distribution (QKD) system, the influence that optical fiber birefringence, temperature variation, asymmetry and coupling ratio have on the interference visibility of the system is studied in details in this paper by using analytic and numerical metIn order to study the interference stability in phase coded quantum key distribution (QKD) system, the influence that optical fiber birefringence, temperature variation, asymmetry and coupling ratio have on the interference visibility of the system is studied in details in this paper by using analytic and numerical methods. Further more, the influence of temperature variation and that of asymmetry could be eliminated and depressed respectively by adjusting of phase modulator in receiver. But the influence of birefringence could not be amended. In addition, the influence of the coupling ratio of coupler is limited to system efficiency only..
Acta Photonica Sinica
- Publication Date: May. 01, 2005
- Vol. 34, Issue 5, 797 (2005)
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