Journals >Chinese Journal of Lasers
Contents
2001
Volume: 28 Issue 7
24 Article(s)
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Research Article
X-ray Emission Properties of Micro-capillary Plasma Irradiated with Femtosecond Intense Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel experiment has been carried out for studying the interaction between ultra short intense laser pulses and glass micro capillary. The X ray emissions from variety capillary lengths and in different laser energy have been measured and analyzed. Experimental results show that owing to the light guide of capillary,A novel experiment has been carried out for studying the interaction between ultra short intense laser pulses and glass micro capillary. The X ray emissions from variety capillary lengths and in different laser energy have been measured and analyzed. Experimental results show that owing to the light guide of capillary, the intensity of X-xay emission is increased intensively when the capillary length is longered. The plasma temperature is estimated by the recombination edge method and found that the temperature is increased with the increasing of the laser pulse energy..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 612 (2001)
Study of Underwater Spot Spread of Collimated Laser Beam
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An anlytical formula for underwater spot spread in the seawater is got from the equation for the light transmitting in media, which can interpret underwater spot spread in seawater with different water quality and different depth successfully.An anlytical formula for underwater spot spread in the seawater is got from the equation for the light transmitting in media, which can interpret underwater spot spread in seawater with different water quality and different depth successfully..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 617 (2001)
Simultaneous Displacement and Temperature Measurement Using One Fiber Bragg Grating
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel displacement and temperature fiber Bragg grating(FBG) sensor based on cantilever structure is presented, and studied both theoretically and experimentally in this paper. FBG is affixed on the adjoiner between the cantilever and a fixed placode. Vertical displacement of the cantilever free end is measured by wavA novel displacement and temperature fiber Bragg grating(FBG) sensor based on cantilever structure is presented, and studied both theoretically and experimentally in this paper. FBG is affixed on the adjoiner between the cantilever and a fixed placode. Vertical displacement of the cantilever free end is measured by wavelength shift of FBG due to the strain action inflicted on FBG by the cantilever. The FBG section attached on cantilever is of different sensitivities to strain and temperature from that attached on the placode due to their making from different materials. Due to the spectral resolution of 0.1nm for spectral analyzer, the resolutions of displacement measurement and temperature measurement are 0.08mm and 3.1℃, respectively (the latter, with a constant displacement, might be 0.73℃), the measurement range of displacement is 10.5 mm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 621 (2001)
Theoretical Analysis and Experimental Investigation of Dispersion Compensation in Transmission Using Uniform Fiber Bragg Gratings
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The principle of dispersion compensation in transmission using uniform fiber Bragg gratings is introduced. Its compensation efficiency is analyzed numerically and the experimental results are reported. It is well know that dispersion compensation in transmission using uniform fiber gratings is a better and more effectiThe principle of dispersion compensation in transmission using uniform fiber Bragg gratings is introduced. Its compensation efficiency is analyzed numerically and the experimental results are reported. It is well know that dispersion compensation in transmission using uniform fiber gratings is a better and more effective compensation scheme comparing with traditional dispersion compensation using chirped fiber gratings..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 625 (2001)
Sectioned Surface Discharge for Pumping XeF(C-A) Lasers
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An optical pump source is constructed on the basis of a sectioned low voltage surface discharge in the form of strictly linear plasma channels with a total working length of 42 cm and characterized by a small time scatter of operation (<100 ns) from the individual sections. The velocity of the dissociation wave and An optical pump source is constructed on the basis of a sectioned low voltage surface discharge in the form of strictly linear plasma channels with a total working length of 42 cm and characterized by a small time scatter of operation (<100 ns) from the individual sections. The velocity of the dissociation wave and the brightness temperature of 15kK in the spectral range 140～170 nm are calculated in terms of the streak photograph of the XeF(C-A) luminescence. Laser radiation on the C A transitions from XeF pumped by this source is obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 629 (2001)
Refraction Microlens Array Made of Bichromate Gelatine by Enzyme Solution with Coding Gray-tone Mask
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel method to fabricate microlens array was proposed. The microlens array was made of bichromate gelatine, exposed by coding gray tone mask and developed by protein enzyme solution. The experiment results were presented.A novel method to fabricate microlens array was proposed. The microlens array was made of bichromate gelatine, exposed by coding gray tone mask and developed by protein enzyme solution. The experiment results were presented..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 633 (2001)
High Precision Straightness Device Based on Double-frequency Laser Interference Technique
[in Chinese], [in Chinese], and [in Chinese]
A high precision straightness standard device based on double frequency laser interference and edge reverse techniques was presented in this paper, in which the laser wave length was taken as the measuring datum. This device which could get the accuracy over 0.1 μm/m under common lab condition was applied in astronautiA high precision straightness standard device based on double frequency laser interference and edge reverse techniques was presented in this paper, in which the laser wave length was taken as the measuring datum. This device which could get the accuracy over 0.1 μm/m under common lab condition was applied in astronautics calibration laboratory..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 637 (2001)
Biomedical Photonics and Laser Medicine
Monte-Carlo Simulation of Emergent Power Distribution of Contact Laser Scalpels
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the principle of geometry optics, the confined equations of light propagation in contact laser scalpels are developed in this paper. By use of the Monte Carlo method, the emergent power distribution of the laser scalpels is simulated, the simulation results are consistent with that of the experimental measuremBased on the principle of geometry optics, the confined equations of light propagation in contact laser scalpels are developed in this paper. By use of the Monte Carlo method, the emergent power distribution of the laser scalpels is simulated, the simulation results are consistent with that of the experimental measurements. Different design parameters that effect the emergent power distribution are discussed comprehensively. The simulation results will be benefit for the design of such scalpels and the determination of treatment schemes..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 664 (2001)
Intrinsic Microscopic Fluorescence and Imaging of Human Lung Tissues
[in Chinese], [in Chinese], S. M. Krishnan, and Chia Teck Chee
The microscopic fluorescence spectra and imaging of excised lung tissue sections were studied under a novel microspectrophotometer system using a He Cd laser light at 442 nm. Differences of the intrinsic autofluorescence distributions in different tissue layers, i.e., epithelium, mucosa and cartilage, were observed in The microscopic fluorescence spectra and imaging of excised lung tissue sections were studied under a novel microspectrophotometer system using a He Cd laser light at 442 nm. Differences of the intrinsic autofluorescence distributions in different tissue layers, i.e., epithelium, mucosa and cartilage, were observed in normal and malignant lung tissues. The results show that the study of microscopic fluorescence on various tissue layers can be used to explore the origin of spectral differences between normal and abnormal lung tissues, which is very useful for the better understanding of the mechanism of the early cancer diagnosis using the laser induced autofluorescence technique..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 669 (2001)
Laser Manufacturing
Pulsed Laser Ablation Deposition of Crystalline ZnSe Thin Films
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Crystalline ZnSe thin films have been deposited on polished GaAs(100) substrates by pulsed laser ablation of a single target of polycrystalline ZnSe solid using KrF 248 nm excimer laser. Chemical etching and high temperature heating were used for pretreatment of substrates. Atomic force microscopy (AFM) shows that the Crystalline ZnSe thin films have been deposited on polished GaAs(100) substrates by pulsed laser ablation of a single target of polycrystalline ZnSe solid using KrF 248 nm excimer laser. Chemical etching and high temperature heating were used for pretreatment of substrates. Atomic force microscopy (AFM) shows that the average roughnesses of ZnSe thin films can reach 3～4 nm. X ray diffraction (XRD) shows that FWHM of ZnSe (400) peaks are 0.4°～0.5°. Analysis of quadruple mass spectroscopy for laser ablated plumes indicates that the plumes consist of Zn, Se and 2Se. It was deduced that ZnSe thin film was grown in two dimensional mode..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 661 (2001)
Laser Physics
Passively-Q-switched Yb:YAG Laser with Cr:YAG as a Saturable Absorber
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Using cw Ti:sapphire laser as pumping source, the passively Q switched Yb:YAG laser with Cr4+:YAG as a saturable absorber has been demonstrated at room temperature. An average output power as much as 55 mW at 1 03 μm with a pulse width (FWHM) as short as 0.35 μs was abtained. The initial transmission of Cr:YAG has inflUsing cw Ti:sapphire laser as pumping source, the passively Q switched Yb:YAG laser with Cr4+:YAG as a saturable absorber has been demonstrated at room temperature. An average output power as much as 55 mW at 1 03 μm with a pulse width (FWHM) as short as 0.35 μs was abtained. The initial transmission of Cr:YAG has influence on the pulse duration (FWHM) and the repetition rate of Yb:YAG passively Q switched laser. The experiment shows that Yb:YAG crystal will be a most promising passively Q switched laser crystal for compact, efficient solid state lasers..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 577 (2001)
Investigation on the Flat-top Mode of a TEA CO2 Laser
[in Chinese], [in Chinese], and [in Chinese]
The output mode of a TEA CO 2 laser is a “flat top” type rather than Gauss distribution predicted by the conventional theory. In this paper, the formation mechanism is investigated. The energy distributions of the output beams in different degree of saturation are measured while the other conditions remain unchanged. IThe output mode of a TEA CO 2 laser is a “flat top” type rather than Gauss distribution predicted by the conventional theory. In this paper, the formation mechanism is investigated. The energy distributions of the output beams in different degree of saturation are measured while the other conditions remain unchanged. It has been demonstrated experimently that the intense saturation due to the high gain in the TEA CO 2 laser is respossible for the output mode′s widening and uniformizing..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 580 (2001)
Study on the Perpendicular Optical Beam Quality of GaInP/AlGaInP Strained Multiple Quantum Well Laser
[in Chinese], [in Chinese], and [in Chinese]
The waveguided mode of 680 nm GaInP/AlGaInP strained multiple quantum well laser is analyzed by using transfer matrix method. Based on the nonparaxial vectorial moment theory of light beam propagation, the perpendicular optical beam quality factor is shown to be far smaller than unity, which is coincided with the experThe waveguided mode of 680 nm GaInP/AlGaInP strained multiple quantum well laser is analyzed by using transfer matrix method. Based on the nonparaxial vectorial moment theory of light beam propagation, the perpendicular optical beam quality factor is shown to be far smaller than unity, which is coincided with the experimental result. This result is useful for understanding the intrinsic nature of the perpendicular semiconductor laser beam..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 583 (2001)
Two-color Coherent Control of Ionization and High Harmonic Generation
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By numerically integrating the one dimensional time dependent SchrAo¨Gdinger equation, the ionization and high harmonic generation of a model atom submitted to two color laser fields are investigated. By considering two different ionization mechanisms: the tunneling ionization regime and the over the barrier ionBy numerically integrating the one dimensional time dependent SchrAo¨Gdinger equation, the ionization and high harmonic generation of a model atom submitted to two color laser fields are investigated. By considering two different ionization mechanisms: the tunneling ionization regime and the over the barrier ionization regime, it is found that the ionization behaviors are quite similar, while the high harmonic generation behaviors are very different. The results demonstrate the possibility of phase control of atomic processes by using two color fields..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 587 (2001)
Experimental Study of Quai-phase-matched Second Harmonic Generation in Annealed Proton-exchanged Lithiun Niobate Waveguides
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, a quai phase matched second harmonic generation (SHG) is reported in proton exchanged lithium niobate waveguide with the fundamental wavelength 1300 nm. 22% SHG efficiency was observed from the periodically poled waveguide with domain inversion by Ti indiffusion.In this paper, a quai phase matched second harmonic generation (SHG) is reported in proton exchanged lithium niobate waveguide with the fundamental wavelength 1300 nm. 22% SHG efficiency was observed from the periodically poled waveguide with domain inversion by Ti indiffusion..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 591 (2001)
Mechanism for Thermal/Electric-field Poling of Fused Silica
[in Chinese], [in Chinese], and [in Chinese]
The mechanism of the second order susceptibility created in the fused silica by thermal/electric field poling is analyzed in detail in this paper. It shows that the second order susceptibility is established by both the orientations of dipoles and third order susceptibility activated by strong static electric field in The mechanism of the second order susceptibility created in the fused silica by thermal/electric field poling is analyzed in detail in this paper. It shows that the second order susceptibility is established by both the orientations of dipoles and third order susceptibility activated by strong static electric field in the depletion region of the sample. Under the ordinary poling condition the former is the main factor, whereas if with the greater poling voltage the latter is the key factor. The expressions for calculating second order susceptibility are deduced, and the numerical calculation is performed. The simulation results show, under the ordinary situation, χ33(2) and χ33(2):χ31(2) are about 1 pm/V and 3, respectively, which are quite consistent with the experimental reports. The theory proves that second order susceptibility can be increased by improving the applied voltage and choosing the silica material with the greater concentration of Na and OH impurity..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 595 (2001)
Enhanced Compression of Femtosecond Soliton in Fibers with Slowly Decreasing Dispersion
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An improved method to compress femtosecond solitons in fibers with slowly decreasing dispersion is proposed. The enhanced compression of fundamental femtosecond solitons can be obtained by combined effects of negative third order dispersion and Raman self scattering in the fibers.An improved method to compress femtosecond solitons in fibers with slowly decreasing dispersion is proposed. The enhanced compression of fundamental femtosecond solitons can be obtained by combined effects of negative third order dispersion and Raman self scattering in the fibers..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 599 (2001)
Picosecond and Femtosecond Laser Induced Darking in Optical Glasses
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Picosecond and femtosecond laser induced darking in some optical glass were studied. Absorption spectra of the original and irradiated glasses were measured. It is believed that the darking was induced by color center generation. The mechanism of the color center generation was demonstrated. Darking area disappeared afPicosecond and femtosecond laser induced darking in some optical glass were studied. Absorption spectra of the original and irradiated glasses were measured. It is believed that the darking was induced by color center generation. The mechanism of the color center generation was demonstrated. Darking area disappeared after heat treatment under 200℃ for a few minutes..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 603 (2001)
Improving Quality of High Energy Femtosecond Laser Pulse by Temporal Filtering
[in Chinese], [in Chinese], and [in Chinese]
The article theoretically analyzes the impact of self phase modulation caused by nonlinear refractive index on ultrashort pulse. A new method, temporal filtering, is proposed for improving quality of femtosecond laser pulse. After analyzing the result of simulation, it is found that the filter method can narrow pulse aThe article theoretically analyzes the impact of self phase modulation caused by nonlinear refractive index on ultrashort pulse. A new method, temporal filtering, is proposed for improving quality of femtosecond laser pulse. After analyzing the result of simulation, it is found that the filter method can narrow pulse and enhance the intensity of pulse. The approach can improve the quality of femtosecond pulse..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 607 (2001)
Optical Communication
Study on the Switching Characteristics of TOAD
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The dynamic gain responses of the semiconductor optical amplifier (SOA) in a terahertz optical asymmetric demultiplexer (TOAD) to intense control pulses with different input energies and pulse widths are investigated. The influences on the switching characteristics of TOAD for control pulse energies, widths, loop′s timThe dynamic gain responses of the semiconductor optical amplifier (SOA) in a terahertz optical asymmetric demultiplexer (TOAD) to intense control pulses with different input energies and pulse widths are investigated. The influences on the switching characteristics of TOAD for control pulse energies, widths, loop′s time asymmetry, and time delays between the signal and control pulses are studied and optimized in detail. The theoretical analysis is compared with the experimental result..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 641 (2001)
Stable Propagation of Chirped Picosecond Optical Pulse in Optical Fiber Links under Higher Order Dispersion Managed
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
It is shown that by numerical simulation, pre chirped picosecond optical pulse can transmit stably in full dispersion compensation optical fiber links considering not only second, but also third order dispersion compensation using dispersion shift fiber with opposite dispersion signs; it eliminates waveform distortion It is shown that by numerical simulation, pre chirped picosecond optical pulse can transmit stably in full dispersion compensation optical fiber links considering not only second, but also third order dispersion compensation using dispersion shift fiber with opposite dispersion signs; it eliminates waveform distortion and peak shift due to the third order dispersion. The optimal pre chirp is relevant to second order dispersion map. During each compensation optical fiber link, pulse width, chirp and peak shift vary around their initial values. It demonstrates that the pre chirp and high order dispersion compensation are two key elements at high bit rate transmission system..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 645 (2001)
Optical Properties and Static Optical Recording Performance of Ag-In-Te-Sb-O Films Using Short-wavelength Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Monolayer Ag In Te Sb O thin films were deposited by reactive RF sputtering using Ag In Te Sb alloy target in a mixture of argon oxygen plasma with different ratio of oxygen to argon. The reflectance spectra and optical constants of the films were studied. It was found that films deposited at P O 2 /P Ar of 2%～4% haMonolayer Ag In Te Sb O thin films were deposited by reactive RF sputtering using Ag In Te Sb alloy target in a mixture of argon oxygen plasma with different ratio of oxygen to argon. The reflectance spectra and optical constants of the films were studied. It was found that films deposited at P O 2 /P Ar of 2%～4% had comparatively large reflectivity, after annealing at 300℃ under protection of argon for 30 minutes, the reflectivity in the wavelength range of 500～700 nm could rise by about 17%～25%; Film deposited at P O 2 /P Ar of 2% had large absorption in the wavelength range of 400～650 nm, the optical constants (n,k) also changed much after annealing. The reflectivity contrast can be as high as 20% after being recorded using short wavelength laser (514 4 nm) with low power (10 mW) and short pulse width (100 ns). The films had good writing sensitivity and certain erasability. The XRD analyses indicated that only Sb crystal formed after annealing, as was different to crystallization characters of Ag-In-Te-Sb films. Components and chemical states of the filmwerean alyzed by XPS. This kind of films had the potential fo rusein high density optical storage..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 650 (2001)
Based on Combining Homomorphic and Adaptive Fuzzy Multilevel Median Filtering for Restoration of Images Degraded by Speckle Noise
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper an algorithm of combining homomorphic and adaptive fuzzy multilevel median filter is proposed, which is applied to restoring images degraded by speckle noise. Simulation result shows the algorithm can not only preserve the geometrical features of images but also effectively suppress speckle noise in imageIn this paper an algorithm of combining homomorphic and adaptive fuzzy multilevel median filter is proposed, which is applied to restoring images degraded by speckle noise. Simulation result shows the algorithm can not only preserve the geometrical features of images but also effectively suppress speckle noise in images. Through comparison, it is proved that the algorithm is superior to the algorithm of combining homomorphic and multilevel median filter..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 655 (2001)
Research on the LD Rapid Scanning Imaging Radar
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This article brought up a method of inspecting the property of the scanner, and applied the method to optic mechanic scanner. Scanning functions of M3 galvanometer scanner under the drive of triangle wave and saw tooth wave instruction functions of several frequencies were measured. Under the supporting of this method This article brought up a method of inspecting the property of the scanner, and applied the method to optic mechanic scanner. Scanning functions of M3 galvanometer scanner under the drive of triangle wave and saw tooth wave instruction functions of several frequencies were measured. Under the supporting of this method a two dimensional rapid scanning laser system was established..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 7, 658 (2001)
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