Ultrafast Laser Fabrication of Capillary Electrospray Emitter Arrays
A. Terekhov, B.K. Canfield, J.M. Jones, T.M. Moeller and L. Costa
Electrospray of an ionic liquid from a two-dimensional (2-D) array of microfluidic capillaries bored through a 200 μm fused silica chip was demonstrated under a 2 × 10-6 torr vacuum. The capillaries were formed using direct-write ultrafast laser micromachining. This novel electrospray emitter design, with capillary emitters embedded inside a solid dielectric, is structurally more robust than current state-of-the-art electrospray emitter designs built around delicate emitters protruding directly into a vacuum. To the best of our knowledge this is the first time this concept is proposed, fabricated, and demonstrated. This innovation is particularly relevant to the development of robust and affordable miniaturized electrospray thrusters, holding hundreds or even thousands of emitters for CubeSat electric micropropulsion applications.
Keywords: Femtosecond laser, SiO2, fused silica, micromachining, electrospray, electric propulsion, ionic liquid, microfluidic capillary emitters