Phase Composition and Electro-Optic Properties of Proton-Exchanged Waveguides in Lithium Niobate Crystals*

Phase Composition of HiVac-VPE Lithium Niobate Optical Waveguides Identified by Spectroscopic Investigations

“…To determine the phase composition of the waveguides, we took into account the data provided by Raman spectroscopy, knowing that each HxLi1−xNbO3 phase has a specific spectrum [9][10][11][12]. Proton exchange influences both vibration modes in Raman spectra, causing intensity reduction of some of the Raman lines, the appearance of new ones, and the appearance of disorder-induced broadening of some Raman bands [9][10][11][12][13][14][15][16][17][18]. The Raman spectra were measured with a LabRAM HR800 spectrometer (Horiba Scientific, Jobin Yvon S.A.S.…”

“…The confocal microscope integrated into the Raman spectrometer, along with the precision and repeatability of the computer-controlled To determine the phase composition of the waveguides, we took into account the data provided by Raman spectroscopy, knowing that each H x Li 1−x NbO 3 phase has a specific spectrum [9][10][11][12]. Proton exchange influences both vibration modes in Raman spectra, causing intensity reduction of some of the Raman lines, the appearance of new ones, and the appearance of disorder-induced broadening of some Raman bands [9][10][11][12][13][14][15][16][17][18]. The Raman spectra were measured with a LabRAM HR800 spectrometer (Horiba Scientific, Jobin Yvon S.A.S.…”

“…Various methods were used to study the H x Li 1−x NbO 3 phases in proton-exchanged LiNbO 3 optical waveguides: X-ray diffraction, M-lines mode spectroscopy, secondary ion mass spectrometry, thermo-gravimetric analysis, differential scanning calorimetry, forward recoil spectrometry, Rutherford backscattering spectrometry, Raman spectroscopy, IR reflection spectroscopy, IR absorption spectroscopy, and UV-VIS absorption spectroscopy . The existence of six to seven phases of H x Li 1−x NbO 3 (depending on the crystallographic orientation of the main surface of the crystal plate) has been established in waveguides fabricated using various proton exchange techniques, including Proton Exchange, Annealed Proton Exchange, Soft Proton Exchange, Vapor-phase Proton Exchange, and High Index Soft Proton Exchange [9,10,15,19,22,25,27]. The specific Raman and IR reflection/absorption spectra are observed for each phase [9][10][11][12][13][14][15][16][17]19,21,24].…”

“…The existence of six to seven phases of H x Li 1−x NbO 3 (depending on the crystallographic orientation of the main surface of the crystal plate) has been established in waveguides fabricated using various proton exchange techniques, including Proton Exchange, Annealed Proton Exchange, Soft Proton Exchange, Vapor-phase Proton Exchange, and High Index Soft Proton Exchange [9,10,15,19,22,25,27]. The specific Raman and IR reflection/absorption spectra are observed for each phase [9][10][11][12][13][14][15][16][17]19,21,24]. Therefore, for identification of any H x Li 1−x NbO 3 phase in waveguides fabricated by other techniques, such as the case of our HiVac-VPE [1][2][3] or Reverse Proton Exchange [24], it is sufficient to use optical spectroscopy data.…”

Phase composition and stress in LiTaO 3 proton-exchanged optical waveguides

“…The angle of incidence was θ = 70 • (measured from the normal to the surface). At such value of θ, the penetration depth of the incident beam is smaller and it is supposed that only the surface phase could contribute to the reflection spectrum [7]. Additionally, a Gaussian deconvolution procedure was performed which allowed us to be more precise when determining the peak frequency and estimating the relative quota of each of the bands building the spectrum (fig.…”