Ultrafast lasers—reliable tools for advanced materials processing

Sugioka, Koji; Cheng, Ya

doi:10.1038/lsa.2014.30

Cited by 1,152 publications

(644 citation statements)

References 139 publications

Supporting

Mentioning

606

Contrasting

Unclassified

Order By: Relevance

“…Here, ωo is the actual beam diameter of the focused Gaussian laser beam [1,2,45]. A two-dimensional (2D) array of nanoholes with diameters smaller than 200 nm was formed on a GaN surface by femtosecond laser ablation at a wavelength of 387 nm based on two-photon absorption using an objective lens with a numerical aperture (NA) of 0.9 [46,47].…”

Section: Nanoablationmentioning

confidence: 99%

“…Ultrafast lasers, which is a generic term for picosecond and femtosecond lasers, have created a new path to laser processing of materials in terms of the capabilities in ultrahigh precision micro-and nanofabrication of not only opaque but also transparent materials and threedimensional (3D) and volume processing [1,2]. The pulse *Corresponding Author: Koji Sugioka: RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan, E-mail: ksugioka@riken.jp width of ultrafast lasers is defined as several tens of femtoseconds to tens of picoseconds, where a pulse width shorter than picoseconds is typically used for fundamental research, while longer pulses are used for commercial and industrial applications because of the high output power and high reliability.…”

Section: Introduction and Historymentioning

confidence: 99%

See 1 more Smart Citation

Progress in ultrafast laser processing and future prospects

Sugioka

2017

Nanophotonics

Self Cite

172

View full text Add to dashboard Cite

Abstract:The unique characteristics of ultrafast lasers have rapidly revolutionized materials processing after their first demonstration in 1987. The ultrashort pulse width of the laser suppresses heat diffusion to the surroundings of the processed region, which minimizes the formation of a heat-affected zone and thereby enables ultrahigh precision micro-and nanofabrication of various materials. In addition, the extremely high peak intensity can induce nonlinear multiphoton absorption, which extends the diversity of materials that can be processed to transparent materials such as glass. Nonlinear multiphoton absorption enables three-dimensional (3D) micro-and nanofabrication by irradiation with tightly focused femtosecond laser pulses inside transparent materials. Thus, ultrafast lasers are currently widely used for both fundamental research and practical applications. This review presents progress in ultrafast laser processing, including micromachining, surface micro-and nanostructuring, nanoablation, and 3D and volume processing. Advanced technologies that promise to enhance the performance of ultrafast laser processing, such as hybrid additive and subtractive processing, and shaped beam processing are discussed. Commercial and industrial applications of ultrafast laser processing are also introduced. Finally, future prospects of the technology are given with a summary.

show abstract

Section: Nanoablationmentioning

confidence: 99%

Section: Introduction and Historymentioning

confidence: 99%

Progress in ultrafast laser processing and future prospects

Sugioka

2017

Nanophotonics

Self Cite

172

View full text Add to dashboard Cite

show abstract

“…Generation of complex structures with high resolution and without the necessity of photomasks are the major advantages of direct laser writing techniques compared to traditional lithography methods. Higher resolutions can be obtained by using two-photon absorption (TPA) where excitation wavelengths in the near-infrared (NIR) were used in combination with femtosecond pulsed lasers [18][19][20]. Recent works also reported possible TPA in visible light [21] or with picosecond pulses [22].…”

Section: Introductionmentioning

confidence: 99%

In vitro degradation and mechanical properties of PLA-PCL copolymer unit cell scaffolds generated by two-photon polymerization

et al. 2016

View full text Add to dashboard Cite

The manufacture of 3D scaffolds with specific controlled porous architecture, defined microstructure and an adjustable degradation profile was achieved using two-photon polymerization (TPP) with a size of 2 × 4 × 2 mm3. Scaffolds made from poly(D,L-lactide-co-ɛ-caprolactone) copolymer with varying lactic acid (LA) and ɛ -caprolactone (CL) ratios (LC16:4, 18:2 and 9:1) were generated via ring-opening-polymerization and photoactivation. The reactivity was quantified using photo-DSC, yielding a double bond conversion ranging from 70% to 90%. The pore sizes for all LC scaffolds were see 300 μm and throat sizes varied from 152 to 177 μm. In vitro degradation was conducted at different temperatures; 37, 50 and 65 °C. Change in compressive properties immersed at 37 °C over time was also measured. Variations in thermal, degradation and mechanical properties of the LC scaffolds were related to the LA/CL ratio. Scaffold LC16:4 showed significantly lower glass transition temperature (Tg) (4.8 °C) in comparison with the LC 18:2 and 9:1 (see 32 °C). Rates of mass loss for the LC16:4 scaffolds at all temperatures were significantly lower than that for LC18:2 and 9:1. The degradation activation energies for scaffold materials ranged from 82.7 to 94.9 kJ mol−1. A prediction for degradation time was applied through a correlation between long-term degradation studies at 37 °C and short-term studies at elevated temperatures (50 and 65 °C) using the half-life of mass loss (Time (M1/2)) parameter. However, the initial compressive moduli for LC18:2 and 9:1 scaffolds were 7 to 14 times higher than LC16:4 (see 0.27) which was suggested to be due to its higher CL content (20%). All scaffolds showed a gradual loss in their compressive strength and modulus over time as a result of progressive mass loss over time. The manufacturing process utilized and the scaffolds produced have potential for use in tissue engineering and regenerative medicine applications.

show abstract

“…It is well known that defects engineering is a general approach to adjust material physical properties of magnetic 9,10 and optical [11][12][13] characteristic. For instance, Xing et al 9 carried out a comprehensive study of the connection between defects and magnetic and optical properties.…”

Section: Introductionmentioning

confidence: 99%

Ferromagnetism in proton irradiated 4H-SiC single crystal

et al. 2015

View full text Add to dashboard Cite

Room-temperature ferromagnetism is observed in proton irradiated 4H-SiC single crystal. An initial increase in proton dose leads to pronounced ferromagnetism, accompanying with obvious increase in vacancy concentration. Further increase in irradiation dose lowers the saturation magnetization with the decrease in total vacancy defects due to the defects recombination. It is found that divacancies are the mainly defects in proton irradiated 4H-SiC and responsible for the observed ferromagnetism.

show abstract

Ultrafast lasers—reliable tools for advanced materials processing

Cited by 1,152 publications

References 139 publications

Progress in ultrafast laser processing and future prospects

Progress in ultrafast laser processing and future prospects

In vitro degradation and mechanical properties of PLA-PCL copolymer unit cell scaffolds generated by two-photon polymerization

Ferromagnetism in proton irradiated 4H-SiC single crystal

Contact Info

Product

Resources

About