Hybrid photonic-plasmonic nano-cavity with ultra-high Q/V
Hongyu Zhang, Yong‐Chun Liu, Chenyang Wang, Nianen Zhang, Cuicui Lu
Abstract
Optical cavities with high figure of merit <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>Q</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mspace width="negativethinmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>V</mml:mi> </mml:mrow> </mml:math> is essential to enhance the interaction of light and matter. Here, a hybrid photonic-plasmonic nano-cavity, consisting of an L3 photonic crystal nano-cavity and plasmonic bowtie nano-antennas, is proposed to have an ultrahigh figure of merit <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>Q</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mspace width="negativethinmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>V</mml:mi> </mml:mrow> </mml:math> of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>8.4</mml:mn> <mml:mo>×</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo stretchy="false">(</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>λ</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi>n</mml:mi> </mml:mrow> <mml:msup> <mml:mo stretchy="false">)</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , which is the highest value ever demonstrated for all previous works about L3-type photonic crystal nano-cavities. The value of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>Q</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mspace width="negativethinmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>V</mml:mi> </mml:mrow> </mml:math> is enhanced by more than 25 times compared to that in a bare L3 photonic crystal nano-cavity and is 60 times greater than plasmonic bowtie nano-antennas. As a result, the single-atom cooperativity parameter is improved by 26 times with respect to a bare L3 photonic crystal nano-cavity, and strong coupling between light and a single emitter is achieved. The proposed structure provides a new platform to achieve strong coupling between light and a single emitter, which holds great potential for applications in quantum optics, quantum information, and nonlinear optics.