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Journal ArticleDOI: 10.1063/1.110793

Proton exchanged depth determination in LiNbO3 from laser induced pyroelectric voltage measurements

15 Nov 1993-Applied Physics Letters (American Institute of Physics)-Vol. 63, Iss: 20, pp 2738-2740
Abstract: We report a new nondestructive technique for the determination of depth of proton exchanged (PE) layers in LiNbO3. Relying on the difference in the magnitudes of measured pyroelectric voltages, induced by an intensity modulated laser beam, on the exchanged and unexchanged regions, the depth of the PE layer has been measured and corroborated by a conventional optical characterization method.

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Topics: Laser (51%)
Citations
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Journal ArticleDOI: 10.1016/S0924-4247(97)01623-3
Abstract: A non-contact, non-destructive technique for the depth profiling of micromachined structures is presented. Based on the mirage or optical-beam deflection method of photothermal spectroscopy, an experimental measurement of a 8 μm step in silicon is given by way of illustration.

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6 Citations

References
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Open accessBook
31 Dec 1959-
Abstract: This classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems.

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Topics: Heat kernel (65%), Fourier number (61%), Thermal conduction (60%) ...read more

21,797 Citations


Journal ArticleDOI: 10.1063/1.93615
Abstract: We describe the fabrication and characterization of optical waveguides formed in LiNbO3 by proton exchange in benzoic acid melts at 200–250 °C. Proton exchange, in LiNbO3 the replacement of lithium ions with protons, takes place when the substrate is immersed in the molten acid. We observe a surface increase in the refractive index of 0.12, for the extraordinary polarization only, with a step function index profile. This is the highest index increase obtainable to date for LiNbO3. Measured diffusion rates for x‐cut crystals are 1.37 μm2/h at T = 249 °C and 0.37 μm2/h at T = 217 °C, so that very deep guides can be formed in short times. Diffusion is somewhat slower in the z direction. The process as described is not useful for y‐cut crystals, since it damgaes this surface. Losses, measured on x‐cut samples, were <0.5 dB/cm. All measurements were made at 0.633 μm.

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Topics: Proton (50%)

664 Citations


Journal ArticleDOI: 10.1364/AO.15.000151
01 Jan 1976-Applied Optics
Abstract: The WKB approximation is used to derive simple equations that predict the shape of the index profile from measured mode indices of a planar optical waveguide. This nondestructive test is a useful tool in the study of diffused guides. The index profile is assumed either to decrease monotonically from the surface or to be symmetrical in the case of a buried guide. The approximation uses straight line segments to connect the measured points. Results are compared with mathematical solutions for exponential, Fermi, and step distributions and with other independent experimental observations of the profile in a nickel-diffused LiNbO(3) guide.

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Topics: Step-index profile (64%), Radiation mode (59%), Waveguide (optics) (55%) ...read more

555 Citations


Journal ArticleDOI: 10.1063/1.336968
Abstract: This paper reports the results of structural analysis of proton‐exchanged lithium niobate optical waveguides fabricated in Z‐, X‐, and Y‐cut substrates immersed in pure benzoic acid Rutherford backscattering spectrometry, nuclear reactions, secondary ion mass spectrometry, scanning electron microscopy, and x‐ray diffraction were used to measure atomic composition profiles and the marked lattice distortion induced by the proton exchange process in the waveguiding layer H and Li concentration measurements indicate an exchange of about 70% of the Li atoms are present in the virgin LiNbO3 crystal

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92 Citations


Journal ArticleDOI: 10.1109/58.143166
Abstract: A method is demonstrated for determination of elastic constants of anisotropic layers on arbitrarily anisotropic and piezoelectric substrates only using the easily measured velocity of surface acoustic waves. By means of a detailed theoretical analysis it is shown that by use of the presented method, the elastic stiffness constants and propagation properties of any nonpiezoelectric isotropic, cubic, or even trigonal layer can be determined. The method is applied to proton-exchanged lithium niobate (PE:LiNbO/sub 3/). Complete measurements of dispersion characteristics of Rayleigh waves on Y-cut PE:LiNbO/sub 3/ and calculated values of all elastic stiffness constants of the proton-exchanged film are reported. >

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Topics: Lithium niobate (55%), Rayleigh wave (55%), Dispersion relation (52%) ...read more

18 Citations