Journals >Chinese Journal of Lasers
Contents
2001
Volume: 28 Issue 11
25 Article(s)
Export citation format
Research Article
Measurement for Uniformity of Groove Depth and Width of CD-R Optical Disc Substrates
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, a testing system for groove geometry of CD R substrates by measuring diffraction orders is introduced. This testing is of particular importance in CD R disc manufacture process because the results fed back from the testing can be used to help optimize recording, developing, metalizing, electroplating andIn this paper, a testing system for groove geometry of CD R substrates by measuring diffraction orders is introduced. This testing is of particular importance in CD R disc manufacture process because the results fed back from the testing can be used to help optimize recording, developing, metalizing, electroplating and replicating processes. Even if the width and depth of groove are not accurately obtained by this system, it is also valuable in CD R disc manufacturing process because the system, which can be used to judge the quality of substrates, is simple, sensitive, quick and non destructive. The results of a same sample tested by our system and an AFM microscope are presented simultaneously..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 994 (2001)
Beam under Pure Bending Used for Tuning of Fiber Bragg Grating without Chirp
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
It is suggested in this paper that the simple beam and the cantilever beam used for tuning FBG will make the FBG chirping. A novel tuning method utilizing the beam under pure bending is introduced. It is proved experimentally and theoretically that this new method will tune the Bragg wavelength without chirp. The FBG eIt is suggested in this paper that the simple beam and the cantilever beam used for tuning FBG will make the FBG chirping. A novel tuning method utilizing the beam under pure bending is introduced. It is proved experimentally and theoretically that this new method will tune the Bragg wavelength without chirp. The FBG external cavity semiconductor laser using this new method has achieved the tuning wavelength of ±1 nm continuously and steadily..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 999 (2001)
Electro-optic Phase Modulator with Thermally Poled PANDA Fiber
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel fiber electro optic phase modulator has been fabricated with the thermal poling of polarization maintaining fiber. A PANDA polarization maintaining fiber polished and deposited with micro strip electrode was poled as applied DC 3000 V voltage on its both sides at temperature 280 ℃. The electro optic coefficientA novel fiber electro optic phase modulator has been fabricated with the thermal poling of polarization maintaining fiber. A PANDA polarization maintaining fiber polished and deposited with micro strip electrode was poled as applied DC 3000 V voltage on its both sides at temperature 280 ℃. The electro optic coefficient of the electro optic phase modulator is 0.47±0.05 pm/V. Because built from polarization maintaining fiber, the phase modulator may be used in all fiber device based on fiber interferometer with polarization stability..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1003 (2001)
Time Delay of Input Short Optical Pulses after Passing Through Fabry-Perot Filters
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, the time delay of input optical pulses after passing through Fabry Perot filters has been investigated theoretically in detail. The results show that the time delay depends on the input pulse width. Also, the difference between the central frequency of the input pulse and the resonant frequence of the fiIn this paper, the time delay of input optical pulses after passing through Fabry Perot filters has been investigated theoretically in detail. The results show that the time delay depends on the input pulse width. Also, the difference between the central frequency of the input pulse and the resonant frequence of the filter has intense influence on the time delay..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1007 (2001)
Biomedical Photonics and Laser Medicine
Report on 45 Patients with Digestive Diseases Who Were Treated by the Nd:YAP Laser with Endoscope
[in Chinese], [in Chinese], and [in Chinese]
The laser of Nd:YAP at 1341.4 nm transferred by fiber has not only coagulation and vaporization in tissue, but also weaker penetrability than that of the laser at 1064 nm, so it has high safety. By using the Nd:YAP laser with endoscope to treat 45 patients with gastroenteric hyper plasic diseases, the results showed thThe laser of Nd:YAP at 1341.4 nm transferred by fiber has not only coagulation and vaporization in tissue, but also weaker penetrability than that of the laser at 1064 nm, so it has high safety. By using the Nd:YAP laser with endoscope to treat 45 patients with gastroenteric hyper plasic diseases, the results showed that the laser of Nd:YAP at 1341.4 nm is a suitable laser for cavum organs by endoscope..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1054 (2001)
Holography and Information Processing
A New Way to Eliminate the Zero-order Image in Digital Holography
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The true image that can be used for recording microscopic objects in digital holography is improved by elimination of zero order image with a digital way. The processing is done by mathematical methods without phase modulator or any other extra equipment. The basic principle and the verifying experiment are described tThe true image that can be used for recording microscopic objects in digital holography is improved by elimination of zero order image with a digital way. The processing is done by mathematical methods without phase modulator or any other extra equipment. The basic principle and the verifying experiment are described too..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1024 (2001)
Laser Manufacturing
Study of the Laser Based Measuring Technique for Smoke and Dust in Emission
[in Chinese], [in Chinese], and [in Chinese]
A laser based technique is proposed which is able to measure and supervise the mass concentration and particle size of smoke and dust in emissions. It is characterized by fast, non contact, on line and continuous measurements and gives a direct results of mass concentration in mg/m 3. Experimental studies proved that tA laser based technique is proposed which is able to measure and supervise the mass concentration and particle size of smoke and dust in emissions. It is characterized by fast, non contact, on line and continuous measurements and gives a direct results of mass concentration in mg/m 3. Experimental studies proved that the proposed method is correct in principle and accurete in the measurements..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1032 (2001)
Effect of Laser Beam Incident Angle on Laser Cutting Quality
[in Chinese], and [in Chinese]
In this paper author describes the result of an experiment which illustrates the effect of laser beam incident angle on laser cutting quality. The experiemnt shows the possibility to get a satisfying cutting quality with the non vertical laser beam to work piece surface. This is quite different from the traditional ideIn this paper author describes the result of an experiment which illustrates the effect of laser beam incident angle on laser cutting quality. The experiemnt shows the possibility to get a satisfying cutting quality with the non vertical laser beam to work piece surface. This is quite different from the traditional ideas which the laser beam must be vertical to work piece surface for laser cutting. In three dimensional laser cutting author gives the way to obtain good cutting quality when the laser beam is not vertical to work piece surface..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1037 (2001)
Theoretical Analysis of the Effects of Pipe Diameter and Laser Beam Diameter on the Initial Instantaneous Absorptivity of Laser Cutting
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The effects of curvature radius(pipe diameter) and laser beam diameter on the initial instantaneous absorptivity of laser cutting for 304 stainless steel pipe and plate were investigated theoretically. The theoretical analysis showed that the pipe diameter D and the laser beam diameter d had important effect on theThe effects of curvature radius(pipe diameter) and laser beam diameter on the initial instantaneous absorptivity of laser cutting for 304 stainless steel pipe and plate were investigated theoretically. The theoretical analysis showed that the pipe diameter D and the laser beam diameter d had important effect on the initial instantaneous absorptivity of laser cutting as the ratio of d to D is bigger than 0 866, and the initial instantaneous absorptivity of laser cutting increases with the pipe diameter (curvature radius) decreases or the laser beam diameter increases..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1041 (2001)
Study on the Laser Repairing Surface Crack of Steel Components
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Surface crack of steel components was repaired with two bundle of laser. There was an obvious joined band between filled region and substrate of component. The microstructures of repaired region were adnate cellular crystal, dendrite crystal, and needleshaped crystal. The phases of dendrite crystal in repaired region wSurface crack of steel components was repaired with two bundle of laser. There was an obvious joined band between filled region and substrate of component. The microstructures of repaired region were adnate cellular crystal, dendrite crystal, and needleshaped crystal. The phases of dendrite crystal in repaired region were consisted of γ Ni which contained plenty of Cu, Fe. The phases in the gaps among dendrite crystals wereγ Ni, NiSi 2, Cr 3Ni 2, CrSi. The hardness of filled layer in repaired region were HV 0.2 400～HV 0.2 450, then the hardness values decreased from the surface to transition region..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1045 (2001)
Study on the Quality of Ni-based Alloy Light Beam Powder Surfacing
[in Chinese], [in Chinese], and [in Chinese]
In this paper, the influence of surfacing technology and material on the quality of light beam Ni based alloy powder surfacing layer was investigated. In order to acquire surfacing layer of quality, the width of pre coating must be smaller than that of light spot. Too big thickness of pre coating can result in the poorIn this paper, the influence of surfacing technology and material on the quality of light beam Ni based alloy powder surfacing layer was investigated. In order to acquire surfacing layer of quality, the width of pre coating must be smaller than that of light spot. Too big thickness of pre coating can result in the poor bond between surfacing layer and base metal. While the pre coating is too thin, the macrohardness of surfacing layer decreases obviously owing to high dilution of base metal. By means of multi layer and multi pass lap surfacing, the surfacing layer with big thickness and area can be acquired. The transverse crack in surfacing layer, porosity in bead edge and non fusion between layers are the defects that are liable to produce when multi layer surfacing is used. When multi pass lap surfacing is used, non lap in the toe of weld can arise because of selected moisture. The reasonable control of heat input, cleaning of former weld and good protection of molten pool are the crucial factors of acquiring surfacing layer with big thickness and area. When adding wettable ceramics (WC with Ni coating) with Ni-based alloy and controlling the content of WC with Ni coating, the high quality of surfacing layer with higher hardness can be acquired..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1049 (2001)
Laser Physics
Investigation of Thermal Recovery of Wavefront Distortion of the Single-segment Amplifier
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The experimental results of the thermal recovery of the wavefront distortion using the single segment amplifier (SSA) test bed and the Hatamann wavefront sensor are reported. The results indicate that the largest values of peak to valley and RMS of the optical wavefront are 1.1λ and 0.13λ (λ=632.8 nm), respectively. ThThe experimental results of the thermal recovery of the wavefront distortion using the single segment amplifier (SSA) test bed and the Hatamann wavefront sensor are reported. The results indicate that the largest values of peak to valley and RMS of the optical wavefront are 1.1λ and 0.13λ (λ=632.8 nm), respectively. The experimental results agree well with the numerical simulations..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 961 (2001)
Beam Quality Improvement by Intracavity Phase Modulation in Solid-state Laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new method to improve laser beam quality by using intracavity phase modulation is presented. The phase modulation is fulfilled by LiNbO 3 electro optic crystal driven by high voltage. The laser used is CW Nd:YAG solid state laser pumped by Krypton lamps. The experimental results show that intracavity phase modulationA new method to improve laser beam quality by using intracavity phase modulation is presented. The phase modulation is fulfilled by LiNbO 3 electro optic crystal driven by high voltage. The laser used is CW Nd:YAG solid state laser pumped by Krypton lamps. The experimental results show that intracavity phase modulation can transfer effectively the laser oscillation mode from multi mode to fundamental mode like beam with smooth intensity profile..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 966 (2001)
All-solid-state Single-frequency and Intracavity-frequency-doubled Nd:YVO4 Laser with Fold-cavity
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Using the mode selection property of the etalon inserted inside the laser resonator a LD pumped single frequency and intracavity frequency doubled CW Nd:YVO 4/KTP laser with fold cavity has been designed and experimentally studied. The maximum single frequency green output power of about 40 mW was obtained at the LD puUsing the mode selection property of the etalon inserted inside the laser resonator a LD pumped single frequency and intracavity frequency doubled CW Nd:YVO 4/KTP laser with fold cavity has been designed and experimentally studied. The maximum single frequency green output power of about 40 mW was obtained at the LD pumping power of 1.5 W. The maximum tunable frequency range for green light is about 200 GHz..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 971 (2001)
Dips of Output Power Curve of LD Pumped Nd:YVO4 Plane-parallel Cavity Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Output characteristics of laser diode pumped Nd:YVO4 plane parallel cavity laser at different thermal lenses are researched. The dips in the output power curves are found and analyzed. The effects of thermal lens effect and resonator lengths on the output characteristics are put forward.Output characteristics of laser diode pumped Nd:YVO4 plane parallel cavity laser at different thermal lenses are researched. The dips in the output power curves are found and analyzed. The effects of thermal lens effect and resonator lengths on the output characteristics are put forward..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 974 (2001)
Investigation of Non-collinear Type-Ⅰ Phase Matched Optic Parametric Amplification Using BBO Crystal
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The non collinear optic parametric amplification using BBO crystal with type Ⅰ phase matched geometry is investigated theoretically. For the certain pump wavelength and signal wavelength, it is indicated that the non collinear incident angle exists with the maximum gain bandwidth and the higher gain. The temperature alThe non collinear optic parametric amplification using BBO crystal with type Ⅰ phase matched geometry is investigated theoretically. For the certain pump wavelength and signal wavelength, it is indicated that the non collinear incident angle exists with the maximum gain bandwidth and the higher gain. The temperature also effects the gain spectrum partly. The theoretical analysis is useful to optimize the optic parametric amplification of the short pulse..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 977 (2001)
Nonlinear Propagation of Extremely Short Optical Pulses with Arbitrary State of Polarization in Isotropic Medium
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The traditional slowly varying envelope method can′t be used for propagation of femtosecond pulse with duration of several optical oscillation periods. By simplifying the electric field's wave equation with unidirectional wave approximation and incorporating the material equation the propagation equation of electriThe traditional slowly varying envelope method can′t be used for propagation of femtosecond pulse with duration of several optical oscillation periods. By simplifying the electric field's wave equation with unidirectional wave approximation and incorporating the material equation the propagation equation of electric field of such extremely short optical pulse can be attained. With this method the new propagation equation of extremely short optical pulse with arbitrary polarization state in isotropic medium has been presented. The interaction between two polarization parts has also been studied numerically..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 981 (2001)
Studies on Some Features of the Closed-aperture Z-scan Curves with Gaussian Laser Beam
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Some features of the closed aperture Z-scan transmittance curves of nonlinear optical materials with Gaussian beam have been studied theoretically when the nonlinear refraction and the nonlinear absorption coexist. It is found that the peak valley or valley peak structure depends on the ratio ρ of the real part to the Some features of the closed aperture Z-scan transmittance curves of nonlinear optical materials with Gaussian beam have been studied theoretically when the nonlinear refraction and the nonlinear absorption coexist. It is found that the peak valley or valley peak structure depends on the ratio ρ of the real part to the imaginary part of the third order nonlinear susceptibility. The exact critical value ρc, which determines whether the peak valley or valley peak structure exists or not, is given; the ρ dependences of some parameters of the transmittance curves are obtained numerically, and the scope of applications for the results is also discussed. The Z-scan experiment of CS 2 is consistent with the theoretical results obtained here..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 985 (2001)
Diffraction Model on Focusing Properties of Phase-modulated Third Harmonic Beams
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the transform of phase aberrations in third harmonic generation, the focusing properties of third harmonic beam with nonlinear crystals having periodic surface ripples were theoretically investigated. A diffraction model has been developed, which can analytically calculate the intensity and angular distributioBased on the transform of phase aberrations in third harmonic generation, the focusing properties of third harmonic beam with nonlinear crystals having periodic surface ripples were theoretically investigated. A diffraction model has been developed, which can analytically calculate the intensity and angular distributions of multi diffraction orders. It provides the design criteria for the third harmonic generation of high energy laser drivers..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 988 (2001)
Quantum Interference between Virtual and Real Photons of the Spontaneous Emission in an Atom Embedded in Photonic Band Gap Structure
[in Chinese], and [in Chinese]
The spontaneous emission is studied with non rotating wave approximation in a three level atom embedded in a photonic band gap structure (PBGS). And the edge of the gap is not located at the center of the two upper levels. Intense quantum interference occurs between the virtual and real photons with a set of suitable pThe spontaneous emission is studied with non rotating wave approximation in a three level atom embedded in a photonic band gap structure (PBGS). And the edge of the gap is not located at the center of the two upper levels. Intense quantum interference occurs between the virtual and real photons with a set of suitable parameters. A new localized field is found in the spontaneous emission field, while the atom is partly trapped in the upper levels..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 991 (2001)
Optical Communication
All-optical Subharmonic and Group Clock Extraction from Unequal-amplitude-sequence Multiplexed OTDM Signals
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel method of all optical subharmonic frequency clock extraction at 2.5 GHz and group clock extraction at 5GHz and 10GHz is demonstrated from 4×2.5 GHz unequal amplitude sequence multiplexed OTDM signals that include dark frame pulses. The dark frame pulses used in OTDM signals can not only be used for data reA novel method of all optical subharmonic frequency clock extraction at 2.5 GHz and group clock extraction at 5GHz and 10GHz is demonstrated from 4×2.5 GHz unequal amplitude sequence multiplexed OTDM signals that include dark frame pulses. The dark frame pulses used in OTDM signals can not only be used for data recognition, but also improve the quality of extracted optical clock..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1010 (2001)
Characteristics of L-Band Erbium Doped Fiber Amplifier Gain Spectra
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The investigation on the characteristics of L Band erbium doped fiber is reported. At the optimum population inversion level (N=0.39), the flattened amplification bandwidth of 22 nm(±0.5 dB) and linear relation between pump power and signal power were demonstrated theoretically and experimentally. Small signal gaiThe investigation on the characteristics of L Band erbium doped fiber is reported. At the optimum population inversion level (N=0.39), the flattened amplification bandwidth of 22 nm(±0.5 dB) and linear relation between pump power and signal power were demonstrated theoretically and experimentally. Small signal gain of 33 dB was achieved at 1572 nm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1013 (2001)
Principle of Birefringence Crystal Type Interleaver Applied in DWDM Fiber System
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Application of interleaver in DWDM fiber communication system is introduced. By means of birefringence crystal plate and polarization beam interference, principle of birefringence crystal type interleaver is analyzed. It is mentioned that a hybrid structure of birefringence crystal type interleaver and film filter is aApplication of interleaver in DWDM fiber communication system is introduced. By means of birefringence crystal plate and polarization beam interference, principle of birefringence crystal type interleaver is analyzed. It is mentioned that a hybrid structure of birefringence crystal type interleaver and film filter is applied in DWDM fiber communication system..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1017 (2001)
Fiber Raman Amplifier's Gain Coefficient and Noise Figure
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Raman gain coefficients of TrueWave TM , DCF and DSF fibers, which are pumped by 1480 nm LD are Measured and compared. Because these distributed fiber Raman amplifiers are usually wanted as the pre amplifiers of optical receiver, the noise figures of the fiber Raman amplifier are measured and calculated.The Raman gain coefficients of TrueWave TM , DCF and DSF fibers, which are pumped by 1480 nm LD are Measured and compared. Because these distributed fiber Raman amplifiers are usually wanted as the pre amplifiers of optical receiver, the noise figures of the fiber Raman amplifier are measured and calculated..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1021 (2001)
Spectroscopy
Automatically Rotation-speed-controlled Layer Thickness of Ultrathin Multilayer Reflectors
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
After getting rid of the interference of RF, automatically rotation speed controlled layer thickness is realized, which not only can accurately fabricate ultra thin multilayers, but also can record the thickness of every layer and automatically change rotation speed and automatically stop rotation after fabrication is After getting rid of the interference of RF, automatically rotation speed controlled layer thickness is realized, which not only can accurately fabricate ultra thin multilayers, but also can record the thickness of every layer and automatically change rotation speed and automatically stop rotation after fabrication is over. Compared with the rotation speed controlled layer thickness monitoring, it′s useful to reduce the intensity of labor and improve the rate of finished products. The advantage is especially obvious in fabricating complicated multilayers..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 11, 1027 (2001)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20