Ribes-Pleguezuelo, P.P.Ribes-PleguezueloPavel, N.N.PavelBeckert, E.E.BeckertDamm, C.C.DammBodemann, A.A.BodemannGrigore, O.-V.O.-V.GrigoreCroitoru, G.G.CroitoruBrandus, C.-A.C.-A.BrandusVasile, N.-T.N.-T.VasileEberhardt, R.R.EberhardtTünnermann, A.A.Tünnermann2022-03-062022-03-062019https://publica.fraunhofer.de/handle/publica/25879410.1117/1.OE.58.6.065101The 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/Cr4+: 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.en620535journal article