This paper describes the coaxial integration of a Michelson interferometer (MI) and a Sagnac interferometer (SI) in a high-speed, phase-sensitive laser probe for surface acoustic wave/bulk acoustic wave devices. This combination enables the MI to be used for calibration of the vibration amplitude captured by the SI without sacrificing the measurement accuracy and speed of the SI-based laser probe. First, the system setup is detailed. Next, simultaneous measurement is performed using the SI and MI, and good coincidence is demonstrated between these measured results after correction of tiny misalignment between two optical axes. This means that the calibration can be performed simply by multiplying the data captured by SI by a coefficient of proportionality; this value of this can be determined by comparison with the data captured by simultaneous measurement for a tiny area. Finally, the procedure for absolute vibration amplitude measurement is proposed and its validity is confirmed by actual measurement.

This paper describes the implementation of the autofocus function for the laser beam into the high-speed, phase-sensitive laser probe system for RF SAW/BAW devices. This implementation can compensate defocus caused during continuous measurements that take dozens of hours. After a brief explanation of the system used in this work, detailed discussion is given on an employed evaluation function indicating focus status, which is a key factor determining autofocus reliability. It is shown that the sum of energy of Laplacians is suitable as the evaluation function, which can be calculated by the image of the probing laser spot captured by a build-in CCD camera. Then, the implementation of the autofocus function into the current system is detailed. It is confirmed that this function can adjust the focus within almost ±20 μm defocus conditions. Finally, it is confirmed how the implemented autofocus function works effectively to keep just-in-focus under the disturbance.

Axially polar-ferroelectric columnar liquid crystals (AP-FCLCs) consist of nanosized axially polarized columnar molecular aggregates arranged in parallel, in which their polar directions can be switched by applying an electric field and maintained after removal of the electric field. However, the problem remains that the induced polarity can be disturbed by external stimuli because liquid crystals are fluid. To solve this problem, we planned to realize a smooth phase transition system from an AP-FCLC phase to a crystal phase without disturbing the induced polar structure. Thus, we designed a urea compound with two biphenyl groups and four 2-butyloctyl groups to achieve the system. As a result, we succeeded in realizing an AP-FCLC compound that transitions from the FCLC phase to the crystal phase at room temperature while maintaining the polarization induced in the FCLC phase, which is expected to enable long-term maintenance of polarization information.

Replacement of stearyl groups with oleyl groups in a discoid molecule induced a rectangular columnar phase at low temperature. Although the molecule has no hydrogen bonding sites, the induced liquid crystal phase showed a highly efficient chiral amplification. The helical packing structure was postulated based on its X-ray diffraction profile and circular dichroism spectra.

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