{"id":{"repo_id":"soton","oai_identifier":"oai:eprints.soton.ac.uk:15474"},"canonical_url":"https://search.dev.ndltd.org/etd/soton/oai:eprints.soton.ac.uk:15474","repository":{"repo_id":"soton","name":"University of Southampton","base_url":"https://eprints.soton.ac.uk/cgi/oai2"},"display":{"title":"Domain engineering techniques and devices in lithium niobate","abstract":"This thesis presents the results from investigations directed at novel approaches to domain engineering single-crystal congruent lithium niobate at the micron/sub-micron scale for practical device applications. <br/><br/>Experimental etch-rate measurements from a parametric study of etch-rates and etch-quality of single-crystal lithium niobate z-faces, as a function of specific ratios for mixtures of HF/HNO<sub>3</sub>, to ascertain whether the widely-employed 1:2 mixture was in fact optimum for achieving the largest differential etch-rates between lithium niobate z-faces, revealed that pure HF produced an etch-rate that is a factor of two higher than that for the more frequently used 1:2 mixture. The observed etch-quality as compared to the 1:2 ratio was also improved for either pure HF or HF/HNO<sub>3</sub> in a 1:4 ratio. A discussion of the etch-chemistry involved, and an explanation of the observed difference in etch-rates between the +z and -z faces has been proposed. The experimental results are also suggestive of a second differential etch-rate between virgin and newly poled z-faces. <br/><br/>The observed variation in the differential etch-rate as a function of time-delay following poling, was suggestive of small atomic displacements following poling, and was quantified by the evidenced shifts in six major Raman spectral peaks. The noticeable modifications in the etch-behaviour of undoped congruent z-cut lithium niobate by pre-illumination with sub-picosecond UV-laser radiation of 248 nm wavelength at energy fluences below the ablation threshold, demonstrates the potential applicability of this technique for µm-scale surface structuring of lithium niobate. <br/><br/>An innovative technique for surface domain-inversion, based on the conventional e-field poling, but involving an intentional over-poling step, was employed to fabricate 1D and 2D periodic structures with good domain uniformity. Domain periods as short as ~1µm have been achieved, and the technique shows full compatibility with standard waveguide fabrication techniques in lithium niobate. Quasi-phase matched harmonic generation at the fundamental wavelength of 1.064 µm, by means of the first-order (G10) reciprocal lattice vector, from a surface hexagonally poled planar annealed proton exchanged waveguide, with domain period of 6.7 µm, was demonstrated. First-order quasi-phase matched blue light generation with reasonable efficiencies at 413.17 nm, with domain periods of 2.47 µm from a surface poled Ti-indiffused channel waveguide was also demonstrated. <br/><br/>Finally a novel route, sequentially employing techniques such as photolithographic patterning, e-field poling, direct-bonding and domain-sensitive differential wet etching for the fabrication of free-standing piezoelectric micro-cantilevers in single-crystal lithium niobate, with MEMS/MOEMS end-applications, was demonstrated.","abstract_html":"This thesis presents the results from investigations directed at novel approaches to domain engineering single-crystal congruent lithium niobate at the micron/sub-micron scale for practical device applications. &lt;br/&gt;&lt;br/&gt;Experimental etch-rate measurements from a parametric study of etch-rates and etch-quality of single-crystal lithium niobate z-faces, as a function of specific ratios for mixtures of HF/HNO&lt;sub&gt;3&lt;/sub&gt;, to ascertain whether the widely-employed 1:2 mixture was in fact optimum for achieving the largest differential etch-rates between lithium niobate z-faces, revealed that pure HF produced an etch-rate that is a factor of two higher than that for the more frequently used 1:2 mixture. The observed etch-quality as compared to the 1:2 ratio was also improved for either pure HF or HF/HNO&lt;sub&gt;3&lt;/sub&gt; in a 1:4 ratio. A discussion of the etch-chemistry involved, and an explanation of the observed difference in etch-rates between the +z and -z faces has been proposed. The experimental results are also suggestive of a second differential etch-rate between virgin and newly poled z-faces. &lt;br/&gt;&lt;br/&gt;The observed variation in the differential etch-rate as a function of time-delay following poling, was suggestive of small atomic displacements following poling, and was quantified by the evidenced shifts in six major Raman spectral peaks. The noticeable modifications in the etch-behaviour of undoped congruent z-cut lithium niobate by pre-illumination with sub-picosecond UV-laser radiation of 248 nm wavelength at energy fluences below the ablation threshold, demonstrates the potential applicability of this technique for µm-scale surface structuring of lithium niobate. &lt;br/&gt;&lt;br/&gt;An innovative technique for surface domain-inversion, based on the conventional e-field poling, but involving an intentional over-poling step, was employed to fabricate 1D and 2D periodic structures with good domain uniformity. Domain periods as short as ~1µm have been achieved, and the technique shows full compatibility with standard waveguide fabrication techniques in lithium niobate. Quasi-phase matched harmonic generation at the fundamental wavelength of 1.064 µm, by means of the first-order (G10) reciprocal lattice vector, from a surface hexagonally poled planar annealed proton exchanged waveguide, with domain period of 6.7 µm, was demonstrated. First-order quasi-phase matched blue light generation with reasonable efficiencies at 413.17 nm, with domain periods of 2.47 µm from a surface poled Ti-indiffused channel waveguide was also demonstrated. &lt;br/&gt;&lt;br/&gt;Finally a novel route, sequentially employing techniques such as photolithographic patterning, e-field poling, direct-bonding and domain-sensitive differential wet etching for the fabrication of free-standing piezoelectric micro-cantilevers in single-crystal lithium niobate, with MEMS/MOEMS end-applications, was demonstrated.","abstract_has_math":false,"creators":["Sones, Collin Lawrence"],"institution":"University of Southampton","degree_name":"Ph.D.","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2003,"date_issued":"2003-08","date_published":"2003-08","updated_at":"2026-07-24T04:35:42Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Sones, Collin Lawrence"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2003-08"]},{"key":"dc:date.issued","label":"Date","values":["2003-08"]},{"key":"dc:publisher.commercial","label":"Dc Publisher Commercial","values":["University of Southampton"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Optoelectronics Research Centre (pre 2011 reorg)","Optoelectronics Research Centre"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Southampton"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://eprints.soton.ac.uk/15474/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Ph.D."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://eprints.soton.ac.uk/15474/1/Sones_2003_thesis_2744.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis presents the results from investigations directed at novel approaches to domain engineering single-crystal congruent lithium niobate at the micron/sub-micron scale for practical device applications. <br/><br/>Experimental etch-rate measurements from a parametric study of etch-rates and etch-quality of single-crystal lithium niobate z-faces, as a function of specific ratios for mixtures of HF/HNO<sub>3</sub>, to ascertain whether the widely-employed 1:2 mixture was in fact optimum for achieving the largest differential etch-rates between lithium niobate z-faces, revealed that pure HF produced an etch-rate that is a factor of two higher than that for the more frequently used 1:2 mixture. The observed etch-quality as compared to the 1:2 ratio was also improved for either pure HF or HF/HNO<sub>3</sub> in a 1:4 ratio. A discussion of the etch-chemistry involved, and an explanation of the observed difference in etch-rates between the +z and -z faces has been proposed. The experimental results are also suggestive of a second differential etch-rate between virgin and newly poled z-faces. <br/><br/>The observed variation in the differential etch-rate as a function of time-delay following poling, was suggestive of small atomic displacements following poling, and was quantified by the evidenced shifts in six major Raman spectral peaks. The noticeable modifications in the etch-behaviour of undoped congruent z-cut lithium niobate by pre-illumination with sub-picosecond UV-laser radiation of 248 nm wavelength at energy fluences below the ablation threshold, demonstrates the potential applicability of this technique for µm-scale surface structuring of lithium niobate. <br/><br/>An innovative technique for surface domain-inversion, based on the conventional e-field poling, but involving an intentional over-poling step, was employed to fabricate 1D and 2D periodic structures with good domain uniformity. Domain periods as short as ~1µm have been achieved, and the technique shows full compatibility with standard waveguide fabrication techniques in lithium niobate. Quasi-phase matched harmonic generation at the fundamental wavelength of 1.064 µm, by means of the first-order (G10) reciprocal lattice vector, from a surface hexagonally poled planar annealed proton exchanged waveguide, with domain period of 6.7 µm, was demonstrated. First-order quasi-phase matched blue light generation with reasonable efficiencies at 413.17 nm, with domain periods of 2.47 µm from a surface poled Ti-indiffused channel waveguide was also demonstrated. <br/><br/>Finally a novel route, sequentially employing techniques such as photolithographic patterning, e-field poling, direct-bonding and domain-sensitive differential wet etching for the fabrication of free-standing piezoelectric micro-cantilevers in single-crystal lithium niobate, with MEMS/MOEMS end-applications, was demonstrated."]},{"key":"dc:format","label":"Dc Format","values":["text"]},{"key":"dc:title","label":"Title","values":["Domain engineering techniques and devices in lithium niobate"]}]}],"canonical_facts":{"dc:creator":["Sones, Collin Lawrence"],"dc:date":["2003-08"],"dc:date.issued":["2003-08"],"dc:description.abstract":["This thesis presents the results from investigations directed at novel approaches to domain engineering single-crystal congruent lithium niobate at the micron/sub-micron scale for practical device applications. <br/><br/>Experimental etch-rate measurements from a parametric study of etch-rates and etch-quality of single-crystal lithium niobate z-faces, as a function of specific ratios for mixtures of HF/HNO<sub>3</sub>, to ascertain whether the widely-employed 1:2 mixture was in fact optimum for achieving the largest differential etch-rates between lithium niobate z-faces, revealed that pure HF produced an etch-rate that is a factor of two higher than that for the more frequently used 1:2 mixture. The observed etch-quality as compared to the 1:2 ratio was also improved for either pure HF or HF/HNO<sub>3</sub> in a 1:4 ratio. A discussion of the etch-chemistry involved, and an explanation of the observed difference in etch-rates between the +z and -z faces has been proposed. The experimental results are also suggestive of a second differential etch-rate between virgin and newly poled z-faces. <br/><br/>The observed variation in the differential etch-rate as a function of time-delay following poling, was suggestive of small atomic displacements following poling, and was quantified by the evidenced shifts in six major Raman spectral peaks. The noticeable modifications in the etch-behaviour of undoped congruent z-cut lithium niobate by pre-illumination with sub-picosecond UV-laser radiation of 248 nm wavelength at energy fluences below the ablation threshold, demonstrates the potential applicability of this technique for µm-scale surface structuring of lithium niobate. <br/><br/>An innovative technique for surface domain-inversion, based on the conventional e-field poling, but involving an intentional over-poling step, was employed to fabricate 1D and 2D periodic structures with good domain uniformity. Domain periods as short as ~1µm have been achieved, and the technique shows full compatibility with standard waveguide fabrication techniques in lithium niobate. Quasi-phase matched harmonic generation at the fundamental wavelength of 1.064 µm, by means of the first-order (G10) reciprocal lattice vector, from a surface hexagonally poled planar annealed proton exchanged waveguide, with domain period of 6.7 µm, was demonstrated. First-order quasi-phase matched blue light generation with reasonable efficiencies at 413.17 nm, with domain periods of 2.47 µm from a surface poled Ti-indiffused channel waveguide was also demonstrated. <br/><br/>Finally a novel route, sequentially employing techniques such as photolithographic patterning, e-field poling, direct-bonding and domain-sensitive differential wet etching for the fabrication of free-standing piezoelectric micro-cantilevers in single-crystal lithium niobate, with MEMS/MOEMS end-applications, was demonstrated."],"dc:format":["text"],"dc:identifier.uri":["https://eprints.soton.ac.uk/15474/1/Sones_2003_thesis_2744.pdf"],"dc:publisher.commercial":["University of Southampton"],"dc:publisher.department":["Optoelectronics Research Centre (pre 2011 reorg)","Optoelectronics Research Centre"],"dc:publisher.institution":["University of Southampton"],"dc:relation.isreferencedby":["https://eprints.soton.ac.uk/15474/"],"dc:title":["Domain engineering techniques and devices in lithium niobate"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["Ph.D."]},"updated_at":"2026-07-24T04:35:42Z"}