Laser-induced microstructures on silicon for laser-driven acceleration experiments

Abstract

Ultrashort laser pulses are used to create surface structures on thin (25 µm) silicon (Si) wafers. Scanning the wafer with a galvanometric mirror system creates large homogeneously structured areas. The variety of structure shapes that can be generated with this method is exemplified by the analysis of shape, height and distance of structures created in the ambient media air and isopropanol. A study of the correlation between structure height and remaining wafer thickness is presented. The comparatively easy manufacturing technique and the structure variety that allows for custom-tailored targets show great potential for high repetition rate ion acceleration experiments.

Review of HPLSE special issue on target fabrication

“…An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments [11] 9. Laser-induced microstructures on silicon for laserdriven acceleration experiments [14] 10. Developing targets for radiation transport experiments at the Omega laser facility [15] 11.…”

“…Submissions for the special issue covered the invited topics and also branched out into broader areas and capabilities. Papers described research on: techniques for the production of targets for inertial confinement fusion (ICF) [1][2][3][4][5][6][7][8] , micro-assembly [3,8,9] , liquid targets [10] , systems for delivery of targets at high repetition rates [5,11,12] , fundamental target fabrication processes [2,4,[13][14][15][16] , low density materials [15,17,18] and metrology methods [7,18,19] . In addition, there were three important review papers [1,5,12] that give an excellent snapshot of the current capabilities across the world.…”

“…A large number of papers cover fundamental techniques in target manufacture including fill-tube design [2] , ultra-thin foils of plastic [13] , graphene [16] and microstructures on silicon for ion sources [14] . Other research published includes beryllium-based ablator materials [4] , low density aerogels, foams, and assemblies (using low density materials) for radiation transport experiments [15] .…”

“…Special issue content Development of target fabrication for laser-driven inertial confinement fusion at research center of laser fusion [1] Permeation fill-tube design for inertial confinement fusion target capsules [2] Fluid sample injectors for X-ray free electron laser at SACLA [10] Efficient offline production of freestanding thin plastic foils for laser-driven ion sources [13] A new spatial angle assembly method of the ICF target [3] An investigation progress toward Be-based ablator materials for the inertial confinement fusion [4] Review on high repetition rate and mass production of the cryogenic targets for laser IFE [5] An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments [11] Laser-induced microstructures on silicon for laser-driven acceleration experiments [14] Developing targets for radiation transport experiments at the Omega laser facility [15] Targets for high repetition rate laser facilities: needs, challenges and perspectives [12] Large-area suspended graphene as a laser target to produce an energetic ion beam [16] Importance of limiting hohlraum leaks at cryogenic temperatures on NIF targets [6] Surface characterization of ICF capsule by AFM-based profilometer [7] Design and fabrication of gas cell targets for laboratory astrophysics experiments on the Orion high-power laser facility [9] REACH compliant epoxides used in the synthesis of Fe(III)-based aerogel monoliths for target fabrication [17] Assembly and metrology of NIF target subassemblies using robotic systems [8] Modeling the mechanical properties of ultra-thin polymer films [19] X-ray computed tomography of adhesive wicking into carbon foam [18] …”

Targets with cone-shaped microstructures from various materials for enhanced high-intensity laser–matter interaction

“…Self-focusing of the subsequent pulses deepens these so-called ripples, eventually resulting in cone-shaped microstructures. Further studies have shown that the size and form of these structures can be adjusted without much effort by changing the laser and processing parameters [12][13][14][15] . This technique is well studied for silicon, but also works with other materials such as titanium or aluminium [16] .…”