[en] Recent experiments have found that a mechanically distorted blue phase can exhibit a primary linear electro-optic (Pockels) effect [F. Castles et al., Nat. Mater. 13, 817 (2014)]. Here, it is shown that flexoelectricity can account for the experimental results and a model, which is based on continuum theory but takes into account the sub-unit-cell structure, is proposed. The model provides a quantitative description of the effect accurate to the nearest order of magnitude and predicts that the Pockels coefficient(s) in an optimally distorted blue phase may be two orders of magnitude larger than in lithium niobate

No abstract available

[en] Integration of optical components with high precision and accuracy will be essential for future quantum applications in communications and sensing. For this, we need low-loss waveguides, quantum-state generation, active modulation, and single photon detection. In this work, I present the fabrication of devices for each element of this list in titanium in-diffused lithium niobate (Ti:LN) using a maskless optical lithography. Using a single lithography system, we can fabricate devices whose structure sizes span six orders of magnitude (from hundreds of nanometers to several centimeters). We demonstrate low-loss waveguiding in Ti:LN, periodic poling for quasi-phase matching, electro-optic modulation, and fabrication of superconducting nanowire single photon detectors (SNSPDs) on silicon with widths in the micrometer range. The versatility gained by using a maskless laser lithography will help developing applications in the field of quantum communications and sensing. While fabrication of SNSPDs on z-cut lithium niobate remains a challenge, we combined multiple devices realized in Ti:LN to demonstrate a first implementation of homodyne detection with off-chip SNSPDs. Interference with vacuum showed that the detector can be used as a linear detector by evaluating the count rate of a SNSPD and that the signal is shot-noise limited. We were able to measure a shot-noise clearance of 49 dB, which is the highest reported clearance for an optical homodyne detector. The results demonstrate the versatility of these detectors for exploring the wave-particle duality of light.

[en] In this paper, the most probable mechanisms of formation of radiation defects have been considered on the example of gamma radiation. The dependence between the number of defects and the change in properties of lithium niobate has been defined by comparing the number of radiation and pre-radiation defects in piezoelectric crystals. (author)

[en] We have observed enhancements of the anti-Stokes Raman signals generated in lithium niobate waveguides in the forward and backward configurations by at least one order of magnitude under the pump power of the microwatt level. These output signals were measured using a single photon detector. The forward and backward propagating anti-Stokes signals exhibited different spectral features

[en] (K_0.45Na_0.45Li_0.04La_0.02)NbO₃–Bi(Ni_0.5Zr_0.5)O₃[(1 − x)KNLLN-xBNZ, 0 ≤ x ≤ 0.02] ceramics were fabricated via a traditional solid state reaction method. The addition of BNZ can enhance the electrical properties of KNLLN ceramics. As x = 0.015, the sample had good performance with high ε_r ~ 1665 and excellent thermal stability (Δε/ε_100°C ≤ ± 12%) from 100 to 447 °C, indicating that this ceramic has potential application prospects in wider working-temperature range. The electrical behavior at high temperatures of (1 − x)KNLLN-xBNZ ceramics was also analyzed. The results show that the relaxation induced by the double ionized oxygen vacancies is thermally activated.

[en] We propose a design for high efficiency narrow-band terahertz generation using multiple stages with dispersion compensation. Terahertz efficiencies of a few percent are predicted.

No abstract available

[en] The method of preparing lithium niobate is suggested which permits to decrease calcination temperature from 500-800 down to 350-400 deg C and to accelerate the process. For this purpose, after operations of mixing alkochol solutions of niobium and lithium alconholates, treatment of the solution prepared by concentrated ammonia separation of sediment from the solvent is performed by evaporation followed by drying and calcination

No abstract available