{"doi":"10.1364/ol.403760","title":"Mid-infrared frequency doubling using strip-loaded silicon nitride on epitaxial barium titanate thin film waveguides","abstract":"Broadband mid-infrared (mid-IR) frequency doubling was demonstrated using nonlinear barium titanate (BTO) thin films. The device has a strip-loaded waveguide structure consisting of top silicon nitride (SiN) strips and an underneath BTO guiding layer. The epitaxial BTO was deposited on a strontium titanate (STO) substrate by pulsed-laser deposition. Through a SiN grating coupler, the pumping mid-IR light at wavelength <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"> <mml:mi>λ</mml:mi> <mml:mo>=</mml:mo> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mn>3.30</mml:mn> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mo>−</mml:mo> </mml:mrow> <mml:mn>3.45</mml:mn> </mml:mrow> </mml:mrow> <mml:mspace width=\"thickmathspace\"/> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mtext>µ</mml:mtext> <mml:mrow class=\"MJX-TeXAtom-ORD\"> <mml:mi mathvariant=\"normal\">m</mml:mi> </mml:mrow> </mml:mrow> </mml:mrow> </mml:math> was coupled into the nonlinear BTO layer, where the spectrum of the near-infrared (NIR) second-harmonic generation was characterized. The developed BTO waveguides provide a platform for mid-IR nonlinear integrated photonics and on-chip quantum optics.","journal":"Optics Letters","year":2020,"id":131217,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9624,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":584619,"name":"Mingzhao Liu","orcid":"0000-0002-0999-5214","position":1,"is_corresponding":false},{"id":584620,"name":"Ming Lu","orcid":"0000-0003-0175-6531","position":2,"is_corresponding":false},{"id":339418,"name":"Pao Tai Lin","orcid":"0000-0002-5417-6920","position":3,"is_corresponding":false},{"id":339417,"name":"Junchao Zhou","orcid":"0000-0001-6320-6354","position":0,"is_corresponding":true}],"reference_count":30,"raw_metadata":null,"created_at":"2026-07-18T23:16:00.235845Z","pmid":"33258811","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}