P225.2 99042422一种新型的激光测距仪理想光源=A new kind ofpreferable light source for laser range finder[刊,中]/柳强,王月珠,姚宝权,王骐(哈尔滨工业大学光电子技术研究所.黑龙江,哈尔滨(150001))//激光技术.—1998,22(5).—298...P225.2 99042422一种新型的激光测距仪理想光源=A new kind ofpreferable light source for laser range finder[刊,中]/柳强,王月珠,姚宝权,王骐(哈尔滨工业大学光电子技术研究所.黑龙江,哈尔滨(150001))//激光技术.—1998,22(5).—298-300报道了用光学参量振荡的方法(OPO),在Nd:YAG激光器上,用受激布里渊散射(SBS)后向放大输出作泵浦源,获得激光测距仪的理想光源(1.57 μm),最大输出能量为21.6 mJ,相应的转换效率为32%。实验结果与理论分析符合得较好。图3参6(赵桂云)P225.2 99042423二极管泵浦的Q开关Nd:YAG激光器及测距样机=Q—switched Nd:YAG laser by diode pumpingand prototype of laser rangefinders[刊。展开更多
By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, ...By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. It is demonstrated that the admixture of │t^2 2（^3T1）e^4T2〉 and │t^3 2 ^2E〉 bases in the wavefunction of RI level of YAG：Crs＋ and its change with pressure play a key role for the PS of RI line. The behaviors of the ＂pure electronic＂ PS of RI line and the PS of RI line due to EPI are different. It is the combined eEect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental results. The systematic analyses and comparisons between the feature of R1-line PS of YAG：Cr^3＋ and the ones of three laser crystals （GSGG：Cr^3＋, GGG：Cr^3＋ and ruby） have been made, and the origin of the difference between them has been revealed.展开更多
A photoacoustic piezoelectric method based on a simplified thermoelastic theory is employed to determine thermal diffusivities of biological tissues. The thermal diffu-sivities of porcine tissues with different prepar...A photoacoustic piezoelectric method based on a simplified thermoelastic theory is employed to determine thermal diffusivities of biological tissues. The thermal diffu-sivities of porcine tissues with different preparation condi-tions, including fresh, dry and specially prepared conditions, are characterized. Comparing the experimental evaluated diffusivities of the tissues in three conditions with each other, it can be seen that the diffusivities of the fresh tissues are the biggest and the diffusivities of the specially prepared tissues are bigger than that of the dry ones generally. The results show that the piezoelectric photoacoustic method is espe-cially effective for determining macro-effective (average) thermal diffusivities of biological materials with micro- inhomogeneity and easy to be performed, which can provide useful information for researching thermal characters of biological tissues.展开更多
This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural a...This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of the finite elements and the transfer matrix methods is used to simulate the interaction of the waves with Bragg and long period gratings. Results show a very good agreement with experimental data. Recent applications such as the writing of gratings under the acoustic excitation and a novel viscometer sensor based on the acousto-optic mechanism are discussed.展开更多
Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advanta...Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages to this field, and fiber-optic acoustic sensors show already performance levels capable of competing with the standard sensors based on piezoelectric transducers. This review presents the recent advances in the field of fiber-optic dynamic strain sensing, particularly for acoustic detection. Three dominant technologies are identified - fiber Bragg gratings, interferometric Mach-Zehnder, and Fabry-Perot configurations - and their recent developments are summarized.展开更多
文摘P225.2 99042422一种新型的激光测距仪理想光源=A new kind ofpreferable light source for laser range finder[刊,中]/柳强,王月珠,姚宝权,王骐(哈尔滨工业大学光电子技术研究所.黑龙江,哈尔滨(150001))//激光技术.—1998,22(5).—298-300报道了用光学参量振荡的方法(OPO),在Nd:YAG激光器上,用受激布里渊散射(SBS)后向放大输出作泵浦源,获得激光测距仪的理想光源(1.57 μm),最大输出能量为21.6 mJ,相应的转换效率为32%。实验结果与理论分析符合得较好。图3参6(赵桂云)P225.2 99042423二极管泵浦的Q开关Nd:YAG激光器及测距样机=Q—switched Nd:YAG laser by diode pumpingand prototype of laser rangefinders[刊。
文摘By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. It is demonstrated that the admixture of │t^2 2（^3T1）e^4T2〉 and │t^3 2 ^2E〉 bases in the wavefunction of RI level of YAG：Crs＋ and its change with pressure play a key role for the PS of RI line. The behaviors of the ＂pure electronic＂ PS of RI line and the PS of RI line due to EPI are different. It is the combined eEect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental results. The systematic analyses and comparisons between the feature of R1-line PS of YAG：Cr^3＋ and the ones of three laser crystals （GSGG：Cr^3＋, GGG：Cr^3＋ and ruby） have been made, and the origin of the difference between them has been revealed.
文摘A photoacoustic piezoelectric method based on a simplified thermoelastic theory is employed to determine thermal diffusivities of biological tissues. The thermal diffu-sivities of porcine tissues with different preparation condi-tions, including fresh, dry and specially prepared conditions, are characterized. Comparing the experimental evaluated diffusivities of the tissues in three conditions with each other, it can be seen that the diffusivities of the fresh tissues are the biggest and the diffusivities of the specially prepared tissues are bigger than that of the dry ones generally. The results show that the piezoelectric photoacoustic method is espe-cially effective for determining macro-effective (average) thermal diffusivities of biological materials with micro- inhomogeneity and easy to be performed, which can provide useful information for researching thermal characters of biological tissues.
文摘This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of the finite elements and the transfer matrix methods is used to simulate the interaction of the waves with Bragg and long period gratings. Results show a very good agreement with experimental data. Recent applications such as the writing of gratings under the acoustic excitation and a novel viscometer sensor based on the acousto-optic mechanism are discussed.
文摘Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages to this field, and fiber-optic acoustic sensors show already performance levels capable of competing with the standard sensors based on piezoelectric transducers. This review presents the recent advances in the field of fiber-optic dynamic strain sensing, particularly for acoustic detection. Three dominant technologies are identified - fiber Bragg gratings, interferometric Mach-Zehnder, and Fabry-Perot configurations - and their recent developments are summarized.
