Surface lithium niobate

Typical current pulses observed for x-cut quartz, z-cut lithium niobate, and y-cut lithium niobate are shown in Fig. 4.3. Following a sharp rise in current to an initial value (the initial rise time is due to tilt, misalignment of the impacting surfaces), the wave shapes show either modest increases in current during the wave transit time for quartz and z-cut lithium niobate... 

Figure 10.11 shows the theoretical dependence of the domain radius on the applied voltage, which was compared to an experimental data obtained in lithium niobate. This calculation was performed in the range of voltages between 0 and 1.4 kV, using Ps = 75/xC/cm2, ec = 30, ea = 84. The surface energy density aw was obtained by a fitting procedure where it was a free parameter as expected, the obtained value aw = 4 mJ/m2 was relatively small. 

Ding, Y. et al. (1995) Second order optical non-linearity of surface crystallised glass with lithium niobate, J. Appl. Phys., 77, 2208-10. 

The most common SAW devices are based on quartz or lithium niobate. Eventually, piezoelectric LB films may be used to launch the surface waves. To date, however, the reported values of the piezoelectric coeflBcients in monolayers are too small (64). In SAW devices, input and output inter-digitated electrodes are defined with lithography. These electrodes perform... 

Surface acoustic wave propagation in lithium niobate substrate along (0,90, 30)... 

To illustrate diffusion, B-site cation movement into lithium niobate, LiNbOj, is described. This material has important optical properties (Chapter 9) and is employed in optical amplifiers, lasers and waveguides. However, the lithium niobate crystals suffer from optical damage when transmitting visible and near-infrared wavelengths. It has been found that B-site doping of surface layers can effectively reduce such damage, and there have been numerous studies on the diffusion of suitable cations such as TT", Zr, Er and Tm, either in isolation or as co-diffusants, into crystals of LiNbOj. 

The power consumption for heating and cooling of samples can be reduced if the temperatures in the device are kept constant in three different regions and the sample is moved between these three regions. This movement can be operated at the surface of a thermostating chip, for example, by electrostatic manipulation or by surface acoustic waves (SAWs). Therefore fluidic transport paths (hydrophilic areas) are defined lithographically in a hydrophobic environment on a piezoactive substrate like lithium niobate. The excitation of SAWs is realized by microlithographically prepared thin-film electrodes. SAW systems are of particular interest... 

Lithium-Niobate and Lithium-Tantalate Lithium-niobate (LN) and lithium-tantalate (LT) are uniaxial p3Toelectrics, having trigonal structure, with spontaneous polarization arising from asymmetrical displacement of lithium relative to the other ions. These materials Tc values are 1,210 °C and 620 °C, respectively. They are always produced commercially in single-crystal forms. Both are much used for surface acoustic wave devices (e.g., high-frequency filters), while LT is used for pyroelectric detection due to its large pyroelectric coefficient and low permittivity. 

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