摘要:

AbstractThe properties of the phase‐conjugate reflectivity are analyzed anew for the self‐pumped four‐wave mixing in which only the two waves, i.e., the forward pump wave and the probe wave, are incident on the photo‐refractive crystal and the phase‐conjugate wave of the forward pump wave is used as the backward pump wave.First, by means of a model in which a Cat‐type phase conjugator is placed outside the interaction region, the equation for the phase‐conjugate reflectivity of self‐pumped four‐wave mixing using a transmission grating is derived. Next, the numerical calculations have been used for the first time to determine the effects of the coupling strength, the probe ratio as the incident intensity ratio of the forward pump wave to the probe wave, and the reflectivity of the Cat‐type phase conjugator on the entire phase conjugate reflectivity. Since the equation describing the phase‐conjugate reflectivity has multiple solutions, the strict analysis of the equation shows that the phase‐conjugate reflectivity has multiple values. Further, the conditions for high phase‐conjugate refl

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790701

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractAn asymptotic method of analysis is studied for the radiation field when the lowest‐order whispering gallery (WG) modes propagating from the concave side of the concave‐to‐convex boundary with a variable radius of curvature are radiated into the free‐space on the convex side. The modal ray congruences of the WG mode are radiated into the free space after being converted to geometrical rays. Both the caustics and the shadow boundaries are created in the space. As the expression of the radiated field near the caustic, the modal rays incident into the concave part are used for deriving the physical optics integral.By applying the high‐frequency asymptotic analysis in the case of two saddle points closely spaced to the evaluation of the integral, the uniform asymptotic solution was derived. Also, as the radiating field on the sufficiently shadow side of the caustic, the complex ray solution was derived. On the other hand, as the radiating field in the transition region near the shadow boundary caused by the convex region, an asymptotic solution was derived in the form of an extension of the conventional UTD (Uniform GTD) to the case where the geometrical ray converted from the modal ray is incident to the boundary. The numerical results obtained by various asymptotic expressions are compared with the reference solution and the geometrical optics figure drawn by the modal ray tracing. The effectiveness of the asymptotic solution and the propagation and radiation phenomena of the WG mode wer

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790702

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractTo the best of the knowledge of the authors, the formulation is carried out for the first time on the finite‐element beam‐propagation method for the analysis of the magnetooptic waveguide in which the structure varies along the propagation direction. The present method is applicable not only to the case in which refractive index difference is small but also to the case for the TE mode and the TM mode propagating in a waveguide with a large refractive index difference. To suppress the spurious reflection from the computational window edges, the transparent boundary condition is appl

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790703

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractIf it is possible to trap elastic wave energy in a localized region of an elastic solid, it is possible to support the solid at a location where no vibration occurs. This enables highly reliable, low‐loss piezoelectric devices to be developed. In this paper various energy‐trapping elastic wave phenomena and vibration are discussed and their applications to various piezoelectric devices such as strip resonators, monolithic filters, piezoelectric transformers, vibratory gyroscopes and SAW devices are descri

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790704

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractGuidelines are given for designing a piezoelectric vibratory gyroscope to be used as an angular velocity sensor. First, a basic equivalent circuit is given and an approximate equation is derived for sensitivity. Based on the equation, guidelines and issues related to improving sensitivity are discussed. The relationship between the output signal and difference in resonance frequencies of the driving and detecting sides is investigated for cases where the angular velocity is either constant or changing sinusoidally with time. The results are then used to determine the resonance frequencies. Furthermore, a design guideline based on an integral equivalent circuit, which has taken the effects of leakage output into consideration, is discussed and an approach is suggested for supporting the gyroscope. Finally, the performances of various gyroscopes are compared and the utility of a piezoelectric gyroscope as an angular velocity sensor is discussed.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790705

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractUsing the deviation of vibration mode axes from their ideal positions, an equivalent circuit is introduced for bending mode‐based cylindrical piezoelectric ceramic vibratory gyroscopes which have interdigital electrodes for both driving and detection. By comparing experimentally determined impedance characteristics with numerically simulated impedance characteristics, it is possible to estimate shifts in a vibration mode axis of a resonator. Furthermore, it is possible to design a high‐performance vibratory gyroscope that produces no output voltage even when it is not subjected to an angular velocity by degenerating two vibratory modes. This degeneracy can be induced by laser machining a groove at the high‐frequency vibration mode

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790706

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractWe reported that zinc oxide (ZnO) films deposited by direct current (DC)‐mode electrocyclotron resonance (ECR) and radio frequency (RF)‐mode ECR sputtering systems had shown excellent piezoelectric properties andc‐axis orientations. The RF‐mode ECR sputtering system was capable of depositing ZnO films on glass substrates without evidence of column and fiber grains in cross‐section analysis while driving a 1.1‐GHz fundamental Rayleigh surface acoustic wave (SAW). In this paper, we investigate the properties of ZnO film deposited by an RF‐magnetron‐mode ECR sputtering system which has added magnets to the outside of a cylindrical zinc metal (Zn) target of the RF‐mode ECR sputtering system. The ZnO film on the glass substrate deposited by this system was capable of driving a 1.3‐GHz fundamental Rayleigh SAW. This shows a higher frequency than the previously reported ZnO film. This film exhibits most of the same effective electromechanical coupling factors (keff) as the theoreticalkeffvalues calculated by finite‐element method (FEM) using the constants of ZnO single crystal (that is, 97 percent of theoretical value) and 0.6 ∼ 3.6 dB lower insertion loss in comparison with the films deposited by the DC‐mode ECR and the RF‐mode ECR. A (1120) plane epitaxial ZnO film was deposited at low temperatures on an R‐plane sapphire substrate using this system and was capable of driving a 2.54‐GHz Sezawa wave. By measuring the photoluminescence property of a thin, 1.2‐μm, epitaxial ZnO film, free exito

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790707

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractIn a shear horizontal surface acoustic wave (SH‐SAW) propagating through a piezoelectric crystal, shear wave and piezoelectric potential due to piezoelectric effect are combined. SH‐SAW can be useful for chemical sensing in the liquid phase. When the load liquid and propagation surface are in contact, the change in the electrical property of the liquid can be detected due to the acoustoelectric interaction. This paper describes a new type of acoustoelectric biosensor with an enzyme membrane on the SH‐SAW propagating plane for detecting pH change in liquid and reports that the SH‐SAW enzyme sensor with urease is highly sensitive in detecting urea. In addition, this paper describes the detection limit, aging characteristic, and high sensitivity of the d

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790708

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractEffects of the deposition rate control process were investigated by measuring adhesion strengths of Al films using the scratch test method. The Al films tested were deposited on glass substrates. The results indicate that the adhesion strength depends strongly on the deposition rate and increased by a factor of three when the deposition rate was increased from 1 nm/s to 10 nm/s. When the deposition rate was accelerated at a constant acceleration rate of 0.01 to 0.05 nm/s2, the adhesion strength was constant regardless of the acceleration rate and the final deposition rate used. Effects of the two‐stage evaporation process also were investigated. In the two‐stage evaporation process, the initial deposition rate was set at a constant value of 1 nm/s. Subsequent deposition rates used were 3 nm/s, 6 nm/s, and 9 nm/s. The thickness ratio of the initially evaporated films to subsequently evaporated films was varied. The results indicate that the adhesion strength decreased with increasing thickness of the initial film. However, when the thickness of the initial film reached 50 nm, the adhesion strength was no longer affected by the subsequent films. Microstructural analyses of the evaporation film indicate that the films with higher adhesion strength had larger particle s

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790709

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY

摘要:

AbstractTo improve performance characteristics of a pyro‐electric infrared sensor, especially voltage responsivity (Rv), noise equivalent power (NEP), and response speed, it is necessary to reduce the heat capacity of an infrared sensing element which is made of Pb(Zr, Ti)O3(PZT) ceramics. A new design for a sensor whose sensing element is made of a thin bulk PZT ceramic plate mounted on a diaphragm fabricated by the Si micromachining method has been proposed and its prototypes have been tested.The prototype sensor has a PZT ceramic plate which is about 10‐μm thick and has a sensing area of 1 × 2 mm2. The new sensor has anRvvalue of 36.3 to 37.9 mV/μW which is about five times higher than a pyroelectric sensor with a 100‐μm thick PZT bulk ceramic plate. The amount of sensor noise was expected to be reduced by half. However, the amount of sensor noise increased by a factor of two. Because of the increase in the sensor noise, the values of NEP were 1.8 to 3.3 × 10−2μW, which is a factor of two to three smaller than the NEP value of the bulk sensor. Furthermore, the rise time decreased to 31 to 35 ms, which is 10 to 20 percent shorter than that of the bulk sensor. Thus, the reduction of sensor noise will be an important challenge f

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790710

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1996

数据来源: WILEY