Journal ArticleDOI
Second-harmonic optimization of computer-generated hologram.
Satoshi Hasegawa,Yoshio Hayasaki +1 more
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TLDR
A method of optimizing a computer-generated hologram based on parallel second harmonic generation is proposed for holographic femtosecond laser processing, which incorporates the width and spatial profile of the pulse into the hologram design.Abstract:
A method of optimizing a computer-generated hologram based on parallel second harmonic generation is proposed for holographic femtosecond laser processing. The method, which we call second harmonic optimization, incorporates the width and spatial profile of the pulse into the hologram design. With this method, we demonstrated parallel laser processing with high quality. Because of the enhanced processing accuracy, smaller structures were processed with a smaller energy than in our previous work. In parallel laser processing with 18 beams on a glass surface, the minimum average diameter of the processed structures was 271 nm when the mean fluence of the beams was 0.88 J/cm(2).read more
Citations
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Adaptive optics in laser processing.
TL;DR: A review of how simple adaptive elements, such as liquid crystal spatial light modulators and digital micromirror devices, are providing many possibilities for advanced control of the laser fabrication process are provided, and the range of applications of adaptive optical laser fabrication is likely to expand.
Journal ArticleDOI
Four-dimensional light shaping: manipulating ultrafast spatiotemporal foci in space and time.
Bangshan Sun,Patrick S. Salter,Clemens Roider,Alexander Jesacher,Johannes Strauss,Johannes Heberle,Michael Schmidt,Martin J. Booth,Martin J. Booth +8 more
TL;DR: It is shown that a phase-only hologram placed in the pupil plane of an objective and illuminated by a spatially chirped ultrashort pulse can be used to generate three-dimensional arrays of spatio-temporally focused spots.
Journal ArticleDOI
Massively parallel femtosecond laser processing.
TL;DR: It was analytically demonstrated that the number of beams is determined by the horizontal number of pixels in the SLM NSLM that is imaged at the pupil plane of an objective lens and a distance parameter pd obtained by dividing the distance between adjacent beams by the diffraction-limited beam diameter.
Journal ArticleDOI
Polarization distribution control of parallel femtosecond pulses with spatial light modulators
Satoshi Hasegawa,Yoshio Hayasaki +1 more
TL;DR: The interval between the diffraction spots was the closest yet reported by avoiding mutual interference among their side lobes by using a parallel femtosecond laser irradiation system with arbitrary polarization distribution control using a pair of spatial light modulators.
Journal ArticleDOI
High-quality generation of a multispot pattern using a spatial light modulator with adaptive feedback
TL;DR: The method iteratively updates a computer generated hologram (CGH) using correction coefficients to improve the intensity distribution of the generated MSP in the optical system using a spatial light modulator with adaptive feedback.
References
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Journal ArticleDOI
Variable holographic femtosecond laser processing by use of a spatial light modulator
TL;DR: In this paper, a femtosecond laser processing system capable of parallel, arbitrary, and variable patterning is proposed, which is achieved by introducing a spatial light modulator displaying a hologram into the system.
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Parallel direct laser writing in three dimensions with spatially dependent aberration correction.
TL;DR: A hologram design process which aims at reducing aberrations in parallel three-dimensional direct laser writing applications by minimising the diffractive power of holograms while retaining the degree of parallelisation is proposed.
Journal ArticleDOI
Programmable focal spot shaping of amplified femtosecond laser pulses.
Nicolas Sanner,Nicolas Huot,Eric Audouard,Christian Larat,Jean-Pierre Huignard,Brigitte Loiseaux +5 more
TL;DR: This work describes the programmable spatial beam shaping of 100-kHz, 4-microJ amplified femtosecond pulses in a focal plane by wave-front modulation and obtains top-hat, doughnut, square, and triangle shapes of 20-microm size.
Journal ArticleDOI
Holographic femtosecond laser processing with multiplexed phase Fresnel lenses
TL;DR: In this article, the diffraction peaks are made uniform by changing the center phase and size of each phase Fresnel lens while taking account of the intensity distribution of the irradiated laser pulse and the spatial frequency response of the SLM.
Journal ArticleDOI
Kinoform design with an optimal-rotation-angle method
TL;DR: Kinoforms (i.e., computer-generated phase holograms) are designed with a new algorithm, the optimalrotation- angle method, in the paraxial domain, in which the height of the kinoform relief in each discrete point is chosen so that the diffraction efficiency is increased.