Lithium niobate on insulator (LNOI) photonics promises to combine the excellent nonlinear properties of lithium niobate with the high complexity achievable by high contrast waveguides. However, to date, fabrication challenges have resulted in high-loss and sidewall-angled waveguides, limiting its applicability. We report LNOI single mode waveguides with ultra low propagation loss of 0.4 dB/cm and sidewall angle of 75°. Our results open the route to a highly efficient photonic platform with applications ranging from high-speed telecommunication to quantum technology.

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Hugoniot equation-of-state data of shock compressed aluminum oxynitride (AlON), consisting of 64.1 mol% Al2O3⋅35.9 mol% AlN with a density of ∼3.68 g/cm3, have been determined to 180 GPa. The relationship between shock velocity (Us) and particle velocity (Up) is expressed by a straight line: Us(km/s)=8.08+0.761Up(km/s). Although there is no evidence of phase transition in the data, the determined Hugoniot of AlON has been compared with those of oxide spinels such as MgAl2O4 and Fe3O4. We discuss the systematics of high pressure phase transitions of spinels that indicate a phase transition to CaTi2O4-type phases. The phase transition to CaTi2O4-type structures implies that the recently discovered Si3N4 spinel also may be transformed into a CaTi2O4-type phase with increasing pressure.

Shock compaction and synthesis of the titanium-silicon ternary carbide ( Ti 3 SiC 2 ) AIP Conf.The dynamic high-pressure behavior and phase stability of titanium-silicon carbide (Ti 3 SiC 2 ), a unique ceramic having metal-like properties, was investigated in this study. Time-resolved measurements of the Hugoniot equation of state, employing a plate impact geometry, were conducted on the Ti 3 SiC 2 samples in the pressure range of 50-120 GPa using a two stage light gas gun. At pressures around 90-120 GPa, Ti 3 SiC 2 was found to transform to a more compressed state. Shock-recovery experiments were also performed on Ti 3 SiC 2 powders at impact velocities of 1.5-2 km/s using a single capsule geometry, with and without the addition of copper powder to vary the shock-loading pressure ͑calculated to be 22-58 GPa͒ and temperature ͑calculated to be up to 3250°C͒ in the sample. No evidence of shock-induced decomposition was observed in these recovery experiments performed on the Ti 3 SiC 2 powders.

Articles you may be interested inHigh-temperature transport properties of Ca 0.98 RE 0.02 MnO 3 − δ ( RE = Sm , Gd, and Dy) Appl. Phys. Lett. 98, 214101 (2011);High room temperature ferromagnetic moment of Ho substituted nanocrystalline BiFeO 3Infrared transmission spectra were measured systematically in polycrystalline La 1Ϫx Ca x MnO 3Ϫ␦ and several systems substituted by other rare earth ͑RE͒ ions such as Sm 3ϩ , Gd 3ϩ , Dy 3ϩ , etc., at La 3ϩ sites or Fe ions at Mn sites but keeping the nominal Mn 4ϩ /Mn 3ϩ Ϸ3/7. Two strong absorption peaks located around 600 and 350 cm Ϫ1 , which are associated with internal phonon modes, i.e., stretching and bending modes of MnO 6 octahedra, have been observed. Both of them are influenced by the concentrations of Ca and other RE ions substituting at the La and Mn sites. The details of the absorption peaks will be discussed on the basis of changes of the bond length of Mn-O and bond angle of Mn-O-Mn in MnO 6 octahedra.

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We have measured time-resolved luminescence spectra of ruby crystal subjected to impact-induced shock compression along the a axis to 36.3 GPa, recording the effect of shock and release waves on ruby R lines as streaks. Near the Hugoniot elastic limit ͑HEL͒, ruby luminescence lines blur, but above the HEL, blurring disappears and a clear image returns with the temporal behavior of luminescence lines differing from that in elastic region. Above the HEL, the luminescence intensity of shock-compressed ruby crystal decreases with increasing shock pressure.

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