{"paper":{"title":"Burst-Mode Ultrafast Laser Welding of Sapphire and Invar Alloy Across Large Interfacial Gaps up to 10 $\\mu$m","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Burst-mode ultrafast laser pulses bridge 10-micrometer gaps between sapphire and Invar alloy to reach 6.3 MPa shear strength.","cross_cats":[],"primary_cat":"physics.optics","authors_text":"Feng Chen, Guochang Jiang, Nan Li, Qingwei Zhang, Rong Su, Rongxian Wen, Shanglu Yang, Yitong Chen, Yu Wang, Yuxuan Li","submitted_at":"2026-05-13T08:49:17Z","abstract_excerpt":"Achieving reliable joining between transparent materials and metals under non-optical-contact conditions remains challenging due to limited energy coupling and uncontrolled interfacial reaction across $\\mu$m-scale gaps. Burst-mode ultrafast lasers provide a potential solution for large-gap welding through temporally distributed energy deposition. However, the underlying interaction mechanisms and achievable joining limits remain unclear. In this study, burst-mode ultrafast laser welding of sapphire to Invar alloy was investigated under controlled interfacial gaps from 3 to 10 $\\mu$m. Cross-sec"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"Notably, at a 10 μm gap, where single-pulse welding fails, burst-mode ultrafast laser welding enables interfacial bridging with a maximum shear strength of 6.3 MPa, representing the highest level among published studies.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the observed interfacial bridging and strength at large gaps result primarily from the temporally distributed energy deposition of burst-mode pulses rather than uncharacterized factors such as surface preparation, exact focusing conditions, or material-specific chemistry.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Burst-mode ultrafast laser welding joins sapphire and Invar across 10 μm gaps with 6.3 MPa shear strength.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Burst-mode ultrafast laser pulses bridge 10-micrometer gaps between sapphire and Invar alloy to reach 6.3 MPa shear strength.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"dd400384656c855d0ac5935456f956509bd7676ba5929f11cc7c18c8e50ba1e5"},"source":{"id":"2605.13191","kind":"arxiv","version":1},"verdict":{"id":"a820da56-159d-41a2-b9f1-1f8565b17977","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T18:58:27.198251Z","strongest_claim":"Notably, at a 10 μm gap, where single-pulse welding fails, burst-mode ultrafast laser welding enables interfacial bridging with a maximum shear strength of 6.3 MPa, representing the highest level among published studies.","one_line_summary":"Burst-mode ultrafast laser welding joins sapphire and Invar across 10 μm gaps with 6.3 MPa shear strength.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the observed interfacial bridging and strength at large gaps result primarily from the temporally distributed energy deposition of burst-mode pulses rather than uncharacterized factors such as surface preparation, exact focusing conditions, or material-specific chemistry.","pith_extraction_headline":"Burst-mode ultrafast laser pulses bridge 10-micrometer gaps between sapphire and Invar alloy to reach 6.3 MPa shear strength."},"references":{"count":48,"sample":[{"doi":"","year":2024,"title":"Femtosecond laser welding of sapphire-copper using a thin film titanium interlayer,","work_id":"ee7b3dfc-d13c-45a5-825b-7a8814ba6d76","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"Laser welding of fiber array units,","work_id":"152b84ca-e767-4127-9b84-c625570851fd","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2021,"title":"Cold spray additive manufacturing of Invar 36 alloy: microstructure, thermal expansion and mechanical properties,","work_id":"3e7ccca4-9261-4539-ae00-30c1865c7cd6","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2025,"title":"High-strength and impermeable sapphire/aluminum joints fabricated by Ultrafast laser microwelding: Microstructures and joining mechanism,","work_id":"604265e1-3aca-4514-8e94-418e6fe5022f","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"Microstructural and properties of Ultrafast laser selective micro-welding joints of sapphire and Invar alloys,","work_id":"a756f209-4e3d-45dd-9530-0a2c680912f3","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":48,"snapshot_sha256":"f5dc5f88dafcada321b28f4abae917108a8c5270c5f64ba10e3dc19ad5a7d70f","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"2a79139d5967b4bcdd438bfce622f8d37f6d492e0afc7fc0196c1c78a400f56d"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}