Optical initiation of nanoporous energetic silicon for safing and arming technologies

Abstract

Nanoporous silicon, commonly recognized for its photoluminescent properties, has gained attention as a new energetic material capable of energy density more than twice that of TNT. The addition of an oxidizer solution to inert nanoporous silicon results in an exothermic reaction when heat, friction, or focused light is supplied to the system. The energetic material can be integrated alongside microelectronics and micro-electro-mechanical systems (MEMS) for on-chip applications. This integration capability, along with the potential for large energetic yield, makes nanoporous energetic silicon a viable material for developing novel MEMS Safing and Arming (S&A) technologies. While ignition of nanoporous energetic silicon has been demonstrated for the purpose of propagation velocity measurements using a YAG laser, in this paper we show optical ignition for potential integration of the energetic with a miniaturized S&A device. Ignition is demonstrated using a 514nm laser at 37.7mW and a power density of 2.7kW/cm² at a stand-off distance of 23cm. Raman spectroscopy verifies that significant stress in porous silicon is produced by a laser operating near the power density observed to ignite porous silicon. Lastly, we integrate the nanoporous energetic silicon with a MEMS S&A, and demonstrate transfer to a firetrain consisting of one primary and one secondary explosive using a thermal initiator to ignite the nanoporous energetic silicon.