Assembly process and optical performances for a golden laser spark-plug device

Abstract

The low-stress Solderjet Bumping technique was employed to assemble the optical components of an increased-robustness laser spark-plug ignition device using the low melting alloys 96.5Sn3Ag0.5Cu and 80Au20Sn. A finite-element-method analysis, optical simulations, and a soldering parametrization test were performed to prove that different optical materials (sapphire, ECO-550, D-ZLaF52LA, TAC4, and N-SF11 glasses) could be fastened to the stainless steel body. The assembled spark-plug device featured a passively Q-switched Nd∶YAG∕Cr 4þ ∶YAG composite ceramic medium and delivered laser pulses with energy variable between 2.40 and 4.70 mJ, with 0.8 ns duration, suitable for inducing air breakdown phenomenon and engine combustion. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Effect of Ca2+ and Mg2+ ions on the sintering and spectroscopic properties of cr‐doped yttrium aluminum garnet ceramics

“…Thus, it is considered to be a perfect saturable absorber to obtain high peak power and high repetition rate pulses. When fabricated as a composite with Nd:YAG, it can also be applied in small‐scale devices such as laser microchips 12 or laser spark‐plug devices to enhance the functioning of combustion engines 13 …”

“…When fabricated as a composite with Nd:YAG, it can also be applied in small-scale devices such as laser microchips 12 or laser spark-plug devices to enhance the functioning of combustion engines. 13 In comparison with rare-earth-doped transparent YAG ceramics, polycrystalline Cr 4+ :YAG is even more complicated to fabricate, because not only porosity and defect-free microstructure are needed, but sufficient conversion efficiency of chromium trivalent ions to tetravalent ions must be also provided. Since the charge of Cr 4+ is larger by one than that of the original cation in YAG, in order to maintain charge balance, a divalent charge compensator is needed to promote the conversion efficiency of Cr 4+ ion 14 .…”