High speed ultrafast laser anisotropic nanostructuring by energy deposition control via near-field enhancement

Abstract

It is challenging to store the exponentially increasing amount of data in the information age. The multiplexed optical data storage with merits of high data density (hundreds of terabytes/disk), low energy consumption, and long lifetime could open a new era in data storage technology. The recent progress in five-dimensional (5D) optical data storage based on anisotropic nanostructures written by femtosecond (fs) laser pulses in transparent materials reveals its potential for real-world applications, but high writing speed and density remain a major challenge. Here, we propose a method for rapid and energy-efficient writing of highly localized anisotropic nanostructures in silica glass by energy modulated megahertz-rate fs pulses. An isotropic nanovoid is initially generated with pulse energy above the microexplosion threshold and then elongated to an anisotropic nanolamella-like structure via the near-field enhancement effect by lower energy pulses, minimizing the unwanted thermal effects from megahertz-rate fs pulses. The anisotropic nanostructures are exploited for 5D data storage with a rate of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>10</mml:mn> </mml:mrow> <mml:mn>6</mml:mn> </mml:msup> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">v</mml:mi> <mml:mi mathvariant="normal">o</mml:mi> <mml:mi mathvariant="normal">x</mml:mi> <mml:mi mathvariant="normal">e</mml:mi> <mml:mi mathvariant="normal">l</mml:mi> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> </mml:math> , corresponding to a demonstrated fast information recording of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>225</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">k</mml:mi> <mml:mi mathvariant="normal">B</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> </mml:math> and a potentially high-density data storage of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>∼</mml:mo> <mml:mn>500</mml:mn> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">T</mml:mi> <mml:mi mathvariant="normal">B</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> <mml:mi mathvariant="normal">i</mml:mi> <mml:mi mathvariant="normal">s</mml:mi> <mml:mi mathvariant="normal">k</mml:mi> </mml:mrow> </mml:math> .