An experimental investigation of solid propellant erosive burning inan acceleration field

Multiphoton lithography offers the minimum feature size available in submicron scale true 3D printing, but excessive femtosecond laser intensity prevents it from leading to higher photon counts. To circumvent away this effect, we present a cascade upconversion strategy, which is a combination of two efficient two-photon upconversion processes to achieve four-photon photopolymerization. In order to demonstrate the advantages and feasibility of this approach, we combine excited state absorption upconversion using high concentration Ho