Photonic engineering of superbroadband near-infrared emission in nanoglass composites containing hybrid metal and dielectric nanocrystals
Zhigang Gao, Haibo Zhu, Bochao Sun, Yingke Ji, Xiaosong Lu, Hao Tian, Jing Ren, Shu Guo, Jianzhong Zhang, Jun Yang, Xiangeng Meng, Katsuhisa Tanaka
Abstract
Photonic media containing hybrid noble metal–dielectric nanocrystals (NCs) represent a wonderland of nanophotonics, with a myriad of uncharted optical functions yet to be explored. Capitalizing on the unique phase separation and spontaneous formation of Au-metal NCs in a gallosilicate glass, we fabricated <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:msup> <mml:mi>Ni</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> -doped transparent nanoglass composites (GCs) containing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:mi>Au</mml:mi> <mml:mtext>-</mml:mtext> <mml:mtext>metal</mml:mtext> <mml:mo>/</mml:mo> <mml:mi>γ</mml:mi> <mml:mtext>-</mml:mtext> <mml:msub> <mml:mi>Ga</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">O</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> -dielectric NCs. Compared with GCs free of Au-metal NCs, the superbroadband near-infrared emission of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m3"> <mml:mrow> <mml:msup> <mml:mi>Ni</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> with a full width at half-maximum over 280 nm is enhanced twice in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m4"> <mml:mrow> <mml:mi>Au</mml:mi> <mml:mtext>-</mml:mtext> <mml:mi>metal</mml:mi> <mml:mo>/</mml:mo> <mml:mi>γ</mml:mi> <mml:mtext>-</mml:mtext> <mml:msub> <mml:mi>Ga</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">O</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> dual-phase GCs. A comparison is given as to the spontaneous emission (SPE) properties of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m5"> <mml:mrow> <mml:msup> <mml:mi>Ni</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> in the dual-phase GCs when pumped resonantly and off-resonantly with the localized surface plasmon resonance band of the Au-metal NCs. The important role of the Au-metal NCs in the SPE enhancement is revealed by theoretical simulation based on the finite-element method. Combining the photonic engineering effect of hybrid <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m6"> <mml:mrow> <mml:mi>Au</mml:mi> <mml:mtext>-</mml:mtext> <mml:mtext>metal</mml:mtext> <mml:mo>/</mml:mo> <mml:mi>γ</mml:mi> <mml:mtext>-</mml:mtext> <mml:msub> <mml:mi>Ga</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">O</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> NCs and the sensitization effect of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m7"> <mml:mrow> <mml:msup> <mml:mi>Yb</mml:mi> <mml:mrow> <mml:mn>3</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m8"> <mml:mrow> <mml:msup> <mml:mi>Ni</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , a record-high enhancement factor of over 10 of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m9"> <mml:mrow> <mml:msup> <mml:mi>Ni</mml:mi> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> NIR emission is achieved, and optical gain is demonstrated in the GCs at the fiber communication wavelength.