Lanthanum titanate, LaTiO3, is an antiferromagnetic Mott insulator with a Ti 3d1 electronic configuration and exhibits an intriguing metallic state in its epitaxial film grown on the SrTiO3 substrate. Here, we explore the driving force of the Mott insulator to metal transition in LaTiO3 epitaxial films by a systematic study of the film growth conditions and biaxial strain using reactive molecular beam epitaxy. Within the achievable range (up to −2.4%) of the biaxial compressive strain in our study, we found that the oxygen incorporation plays a more crucial role than the biaxial epitaxial strain in the Mott insulator to metal transition in LaTiO3 films.

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Based on the radio frequency (RF) demodulation technique, a novel dual-wavelength fiber laser sensor is proposed and demonstrated experimentally. A beat sensing signal, which is generated by the coherently mixing output of a dual-wavelength laser in a high frequency photodetector, has been obtained and demodulated by a radio-frequency spectrum analyzer (RFSA). By employing a LiNbO 3 modulator, high-frequency beat signal can be tuned arbitrarily to tens or hundreds of megahertz without distortion and thus a lowfrequency RFSA can be used. When a strain is applied on the laser sensor, the detected beat signals will be shifted with a strain sensitivity of about −8.11 kHz/με.