Light coupling and distribution for <inline-formula><math display="inline" overflow="scroll"><mrow><msub><mi mathvariant="normal">Si</mi><mn>3</mn></msub><msub><mi mathvariant="normal">N</mi><mn>4</mn></msub><mo>∕</mo><mi mathvariant="normal">Si</mi><msub><mi mathvariant="normal">O</mi><mn>2</mn></msub></mrow></math></inline-formula… | Publicación