Raman characterization of H:LiNbO3 waveguides

People Infer Recursive Visual Concepts from Just a Few Examples

“…Compared to the best object recognition systems, people learn richer concepts from fewer examples. Recent research in cognitive science, machine learning, and computer vision has begun to model learning as a form of program induction (Zhu & Mumford, 2006;Savova & Tenenbaum, 2008;Savova et al, 2009;Stuhlmuller et al, 2010;Piantadosi, 2011;Piantadosi et al, 2012;Khemlani et al, 2013;Goodman et al, 2015;Lake et al, 2015;Ellis et al, 2015;Yildirim & Jacobs, 2015;Rothe et al, 2017;Amalric et al, 2017;Ellis et al, 2018;Depeweg et al, 2018), yet there are steep computational obstacles to building a general purpose program learner. It is unclear how the mind could learn genuine programs in a general way.…”

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

“…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.…”

“…It is worth noting that the "paraelectric band" at 690 cm −1 is a specific feature of the β i -phases [9,10,[12][13][14][15][16]. For example, in Proton Exchange (PE) waveguides with β iphases, the double peak (630 and 690 cm −1 ) is observed [9,[12][13][14]17].…”

“…It is worth noting that the "paraelectric band" at 690 cm −1 is a specific feature of the β i -phases [9,10,[12][13][14][15][16]. For example, in Proton Exchange (PE) waveguides with β iphases, the double peak (630 and 690 cm −1 ) is observed [9,[12][13][14]17]. In APE waveguides after short-time annealing, the broad band centered with a maximum at 652-656 cm −1 and a broad shoulder at ~660-676 cm −1 is observed [9,10,[12][13][14]17], similar to spectra of the investigated HiVac-VPE samples.…”

“…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.…”