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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

LiNbO3 Cylinder Fiber

We have successfully fabricate optical fiber with a thin layer of LiNbO3 at the boundary of the glass core and clear glass cladding. The construction of this fiber is based on our successful Semiconductor Cylinder Fibers (SCF). A schematic representation of a LiN bo, Cylinder Fiber. These fibers can be used as light modulators, sonar detectors and in other applications. The core diameter of the fiber is sufficiently small compared to the light wavelength and the indices of refraction of the core and cladding glasses are sufficiently close in value so that there is sufficient light at the core cladding boundary to interact with the LiNbO3 layer. This fiber functions best when just a single light mode propagates through the fiber. The idea for a LiNbO3 Cylinder Fiber came from Dr. Tracee Jamison of NASA. The optical properties of LiNbO3 can be changed with strain or the application of an electric field. Thus these fibers can be used as acoustic sensors as for example in a sonar. They can also be used as electric field operated light modulators. However, for this application the fibers would be made with a cross section in the form of a "D". The core with its surrounding LiNbO, layer would be close to the flat portion of the "D" shaped fiber. Two metal contacts would be deposited on the flat portion of the fiber on either side of the core. A voltage applied across these contacts will result in an electric field in the core region that can be used for modulating the optical properties of the LiNbO3 layer. To our knowledge this is the first ever LiNbO3 Cylinder Fiber made.

Kornreich, Philip↗
NASA NTRS2004

LiNbO3 Cylinder Fiber

We have successfully fabricate optical fiber with a thin layer of LiNbO3 at the boundary of the glass core and dear glass cladding. The construction of this fiber is based on our successful Semiconductor Cylinder Fibers (SCF). A schematic representation of a LiNbO3 Cylinder Fiber is shown. These fibers can be used as light modulators, sonar detectors and in other applications. The core diameter of the fiber is sufficiently small compared to the light wavelength and the indices of refraction of the core and cladding glasses are sufficiently close in value so that there is sufficient light at the core cladding boundary to interact with the LiNbO3 layer. This fiber functions best when just a single light mode propagates through the fiber. The idea for a LiNbO3 Cylinder Fiber came from Dr. Tracee Jamison of NASA. The optical properties of LiNbO3 can be changed with strain or the application of an electric field. Thus these fibers can be used as acoustic sensors as for example in a sonar. They can also be used as electric field operated light modulators. However, for this application the fibers would be made with a cross section in the form of a 'D'. The core with its surrounding LiNbO, layer would be close to the flat portion of the 'D' shaped fiber. Two metal contacts would be deposited on the flat portion of the fiber on either side of the core. A voltage applied across these contacts will result in an electric field in the core region that can be used for modulating the optical properties of the LiNbO, layer. To our knowledge this is the first ever LiNbO, Cylinder Fiber made.

Source record↗
NASA NTRS1974

A 1.4-4-micron high-energy angle-tuned LiNbO3 parametric oscillator

The performance characteristics of a widely tunable infrared source that can be rapidly and conveniently angle tuned over the entire 1.4-4.4 micron range are reported. It is significant that the source requires only one set of optics and a single LiNbO3 crystal to tune the entire range. Conversion efficiencies of 15% and an operating amplitude stability of better than 3% have been demonstrated. The availability of large 15-mm-diam by 5-cm-long 47-deg cut LiNbO3 crystals makes possible oscillator operation at up to 2 J of 1.06-micron input pulse energy.

Herbst, R. L.↗
NASA NTRS1977

Simultaneous holographic and photocurrent studies of the photorefractive effect in LiTaO3 and LiNbO3

In reduced LiNbO3:Mn both the photorefractive sensitivity and the simultaneously measured photocurrent result from drift with a polarization-dependent effective 'internal field' of about 6 kV/cm. In reduced undoped LiTaO3 the observed difference in applied fields of the minimum photorefractive sensitivity and zero photocurrent imply charge transport is by a mechanism that cannot be completely described by diffusion and drift in an electric field. The direct measurement of the harmonic content of phase gratings written in several LiNbO3 and LiTaO3 crystals shows termination of charge-transport results from the space-charge field of the hologram.

Spinhirne, J. M.↗
NASA NTRS1982

Sputtering of Al2O3 and LiNbO3 in the electronic stopping region

Because of recent interest in the role played by the thermal properties of materials that exhibit high energy sputtering, Al2O3 and LiNbO3 were sputtered with chlorine ions at energies between 3 MeV and 25 MeV. To detect the sputtered Al and Nb we employ thin carbon catcher foils, which are analyzed with Rutherford scattering in the forward direction. Al surface densities of 10 to the 14th/sq cm and Nb surface densities of 10 to the 13th/sq cm are easily measured. The sputtering yields for both Al2O3 and LiNbO3 increase rapidly with increasing chlorine energy, and the Al and Nb yields are both approximately 0.2 at 20 MeV. Tests for dose, beam current, and contamination effects will be discussed.

Qiu, Y.↗
NASA NTRS2002

Fabry-Perot Interferometer-Based Electrooptic Modulator using LiNbO3 and Organic Thin Films

We report the study of a Fabry-Perot electro-optical modulator using thin crystalline film NPP, and Crystalline LiNbO3. We are able to observe 14, and 60 percent degree of modulation. Measurements were carried using a standard lock-in amplifier with a silicon detector. The proposal to design a Fabry-Perot electro-optic modulator with an intracavity electro-optically active organic material was based on the initial results using poled polymer thin films. The main feature of the proposed device is the observation that in traditional electrooptic modulators like a Packets cell, it requires few kilovolts of driving voltage to cause a 3 dB modulation even in high figure-of-merit electrooptic materials like LiNbO3. The driving voltage for the modulator can be reduced to as low as 10 volts by introducing the electrooptic material inside die resonant cavity of a Fabry-Perot modulator. This is because the transmission of the Fabry-Perot cavity varies nonlinearly with the change of refractive index or phase of light due to applied electric field.

Banks, C.↗
DOE OSTI2020

Materials Data on LiNbO3 by Materials Project

LiNbO3 is Calcite structured and crystallizes in the trigonal R3c space group. The structure is three-dimensional. Li1+ is bonded to six equivalent O2- atoms to form distorted LiO6 pentagonal pyramids that share corners with three equivalent NbO6 octahedra, corners with six equivalent LiO6 pentagonal pyramids, edges with three equivalent NbO6 octahedra, and a faceface with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are three shorter (2.09 Å) and three longer (2.27 Å) Li–O bond lengths. Nb5+ is bonded to six equivalent O2- atoms to form distorted NbO6 octahedra that share corners with six equivalent NbO6 octahedra, corners with three equivalent LiO6 pentagonal pyramids, edges with three equivalent LiO6 pentagonal pyramids, and a faceface with one LiO6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 41°. There are three shorter (1.90 Å) and three longer (2.18 Å) Nb–O bond lengths. O2- is bonded in a distorted see-saw-like geometry to two equivalent Li1+ and two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiNbO3 by Materials Project

LiNbO3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Li1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All Li–O bond lengths are 2.00 Å. Nb5+ is bonded to six equivalent O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 37°. All Nb–O bond lengths are 2.01 Å. O2- is bonded in a 3-coordinate geometry to one Li1+ and two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiNbO3 by Materials Project

LiNbO3 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.01–2.58 Å. In the second Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.05–2.36 Å. In the third Li1+ site, Li1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.01–2.56 Å. In the fourth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.37 Å. In the fifth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.36 Å. In the sixth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.36 Å. In the seventh Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.36 Å. In the eighth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.40 Å. In the ninth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.36 Å. In the tenth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.04–2.39 Å. There are ten inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 36–41°. There are a spread of Nb–O bond distances ranging from 1.92–2.16 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 34–39°. There are a spread of Nb–O bond distances ranging from 1.92–2.14 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 34–40°. There are a spread of Nb–O bond distances ranging from 1.92–2.13 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–40°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the fifth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–40°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the sixth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the seventh Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–40°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the eighth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the ninth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the tenth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 38–41°. There are a spread of Nb–O bond distances ranging from 1.91–2.18 Å. There are thirty inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two Nb5+ atoms. In the second O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted corner and edge-sharing OLi2Nb2 trigonal pyramids. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+ and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+ and two Nb5+ atoms. In the fifth O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted corner and edge-sharing OLi2Nb2 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+ and two Nb5+ atoms. In the eighth O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted corner and edge-sharing OLi2Nb2 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twelfth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two Nb5+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twentieth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+ and two Nb5+ atoms. In the twenty-fifth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-seventh O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-eighth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-ninth O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted corner and edge-sharing OLi2Nb2 trigonal pyramids. In the thirtieth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiNbO3 by Materials Project

LiNbO3 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.97–2.66 Å. In the second Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.32 Å. In the third Li1+ site, Li1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.99–2.60 Å. In the fourth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.34 Å. In the fifth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.33 Å. In the sixth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.35 Å. In the seventh Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.33 Å. In the eighth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.03–2.36 Å. There are eight inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 36–41°. There are a spread of Nb–O bond distances ranging from 1.90–2.18 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–40°. There are a spread of Nb–O bond distances ranging from 1.91–2.15 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–40°. There are a spread of Nb–O bond distances ranging from 1.91–2.16 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 40–41°. There are a spread of Nb–O bond distances ranging from 1.90–2.17 Å. In the fifth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–41°. There are a spread of Nb–O bond distances ranging from 1.90–2.18 Å. In the sixth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 40–41°. There are a spread of Nb–O bond distances ranging from 1.90–2.18 Å. In the seventh Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 40–41°. There are a spread of Nb–O bond distances ranging from 1.90–2.18 Å. In the eighth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 40–41°. There are a spread of Nb–O bond distances ranging from 1.90–2.18 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+ and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+ and two Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+ and two Nb5+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to two Li1+ and two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twelfth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two Nb5+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the eighteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+ and two Nb5+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twentieth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to two Li1+ and two Nb5+ atoms. In the twenty-fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+ and two Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiNbO3 by Materials Project

LiNbO3 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with four NbO6 octahedra, edges with three equivalent LiO6 octahedra, and edges with four NbO6 octahedra. The corner-sharing octahedra tilt angles range from 10–27°. There are a spread of Li–O bond distances ranging from 2.07–2.42 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with four NbO6 octahedra, edges with three equivalent LiO6 octahedra, and edges with four NbO6 octahedra. The corner-sharing octahedra tilt angles range from 10–27°. There are a spread of Li–O bond distances ranging from 2.07–2.42 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four LiO6 octahedra, edges with three equivalent NbO6 octahedra, and edges with four LiO6 octahedra. The corner-sharing octahedra tilt angles range from 10–27°. There are a spread of Nb–O bond distances ranging from 1.98–2.07 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four LiO6 octahedra, edges with three equivalent NbO6 octahedra, and edges with four LiO6 octahedra. The corner-sharing octahedra tilt angles range from 10–27°. There are a spread of Nb–O bond distances ranging from 1.98–2.07 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+ and two Nb5+ atoms. In the third O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted edge and corner-sharing OLi2Nb2 trigonal pyramids. In the fourth O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted edge and corner-sharing OLi2Nb2 trigonal pyramids. In the fifth O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted edge and corner-sharing OLi2Nb2 trigonal pyramids. In the sixth O2- site, O2- is bonded to two Li1+ and two Nb5+ atoms to form a mixture of distorted edge and corner-sharing OLi2Nb2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Three-dimensional reconstruction of THz near-fields from a LiNbO3 optical rectification source

Terahertz (THz) generation by optical rectification in LiNbO3 (LN) is a widely used technique for generating intense THz radiation. The spatiotemporal characterization of THz pulses from these sources is currently limited to far-field methods. While simulations of tilted pulse front THz generation have been published, little work has been done to measure the near-field properties of the THz source. A better understanding of the THz near-field properties will improve optimization of THz generation efficiency, transport, and coupling. We demonstrate a technique for quantitative spatiotemporal characterization of single-cycle strong-field THz pulses with 2-D near-field electro-optic imaging. We have reconstructed the full temporal 3D THz near-field and shown how the phase front can be tailored by controlling the incident pump pulse.

Gabriel, Annika↗
DOE OSTI2020

Structure Analysis of Natural Wangdaodeite—LiNbO3-Type FeTiO3

This paper reports the first structure refinement of natural wangdaodeite, LiNbO3-type FeTiO3 from the Ries impact structure. Wangdaodeite occurs together with recrystallized ilmenite clasts in shock melt veins which have experienced peak shock pressures of between 17 and 22 GPa. Comparison of natural and synthetic wangdaodeite points toward a correlation between the distortion of ferrate- and titanate-polyhedra and the c/a ratio of the unit cell. The Raman spectrum of wangdaodeite is calculated based on the refined structure. Comparison to the reported spectrum of the type-material shows that the Raman peak at 738–740 cm−1 is indicative for this phase, whereas other features in type-wangdaodeite are tentatively assigned to disordered ilmenite.

58 GEOSCIENCES↗
DOE OSTI2022

High-Quality Dry Etching of LiNbO3 Assisted by Proton Substitution through H2-Plasma Surface Treatment

The exceptional material properties of Lithium Niobate (LiNbO3) make it an excellent material platform for a wide range of RF, MEMS, phononic and photonic applications; however, nano-micro scale device concepts require high fidelity processing of LN films. Here, we reported a highly optimized processing methodology that achieves a deep etch with nearly vertical and smooth sidewalls. We demonstrated that Ti/Al/Cr stack works perfectly as a hard mask material during long plasma dry etching, where periodically pausing the etching and chemical cleaning between cycles were leveraged to avoid thermal effects and byproduct redeposition. To improve mask quality on X- and Y-cut substrates, a H2-plasma treatment was implemented to relieve surface tension by modifying the top surface atoms. Structures with etch depths as deep as 3.4 µm were obtained in our process across a range of crystallographic orientations with a smooth sidewall and perfect verticality on several crystallographic facets.

36 MATERIALS SCIENCE↗
NASA NTRS1978

'Smart', remote holographic processor based on the materials characteristics of LiNbO3

A class of 'Smart' remote holographic processors based on the material characteristics of LiNbO3 is introduced. The processors rely on holographic subtraction to detect differences in optical wavefronts that are spatially modulated to reflect either incoming or reference information. The state of the art of their fabrication and performance is described in the following paper. This paper outlines the principles of holography and photorefractivity that make these processors possible. Particular emphasis is placed on a potential mode of operation termed self-subtraction, in which the holographic processor is able to adapt to changes in reference information without the need for commands from an external operator.

Vahey, D. W.↗
NASA NTRS1982

Design, fabrication and evaluation of chalcogenide glass Luneburg lenses for LiNbO3 integrated optical devices

Optical waveguide Luneburg lenses of arsenic trisulfide glass are described. The lenses are formed by thermal evaporation of As2S3 through suitably placed masks onto the surface of LiNbO3:Ti indiffused waveguides. The lenses are designed for input apertures up to 1 cm and for speeds of f/5 or better. They are designed to focus the TM sub 0 guided mode of a beam of wavelength, external to the guide, of 633 nm. The refractive index of the As2S3 films and the changes induced in the refractive index by exposure to short wavelength light were measured. Some correlation between film thickness and optical properties was noted. The short wavelength photosensitivity was used to shorten the lens focal length from the as deposited value. Lenses of rectangular shape, as viewed from above the guide, as well as conventional circular Luneburg lenses, were made. Measurements made on the lenses include thickness profile, general optical quality, focal length, quality of focal spot, and effect of ultraviolet irradiation on optical properties.

Wood, V. E.↗
NASA NTRS1985

Reversing Optical Damage In LiNbO3 Switches

One symptom of optical damage in Ti-diffused LiNbO3 directional-coupler switch reversed by temporarily raising input illumination to higher-thannormal power level. Healing phenomenon used to restore normal operation, increase operating-power rating, and stabilize operating characteristics at lower powers. Higher operating power is tolerated after treatment.

Gee, C. M.↗
NASA NTRS1987

Ti:LiNbO3 components for a fiber gyroscope

It is maintained that integrated optics will play a major role in the next generation of fiber gyros since the potential exists for mass producing low-cost integrated gyro front-end circuits. Ti:LiNbO3 wave guide technology has been used to demonstrate all the necessary components. The combined use of the 3dB splitter and polarizer functions in a 3 x 3 directional coupler is considered. Such a device was designed for operation at lambda = 1.3 microns and fabricated with 6.5-micron Ti strip widths, and a 1050 C/6 hr diffusion.

Minford, W. J.↗