Complex beam profiles for laser annealing of thin-film CdTe photovoltaics

Goffin, Nicholas J.; Tyrer, John R.; Woolley, Elliot

doi:10.2351/1.5038072

Cited by 5 publications

(3 citation statements)

References 23 publications

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“…Forming different structured laser beams of different wavelengths with autofocusing properties is very important in industrial applications. Such laser beams will be exploited in material processing (ablation, scribing, and annealing) [22][23][24][25][26], laser fabrication of volume (3D) structures [27,28], and optical manipulation in different mediums [29][30][31] due to its self-healing properties [32]. Moreover, we plan to extend our work on the propagation of ALBs through a turbulent media, by considering the role of amplitude of azimuthal sinusoidal phase for various values of m.…”

Section: Discussionmentioning

confidence: 99%

Generating autofocused aberration laser beams with different spectral performance

Reddy

Хонина

Pal

2020

J. Opt.

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We present a flexible approach for generating autofocused aberration laser beams (ALBs) of different wavelengths based on the diffractive optical element (DOE) design with distinct phase transmittance that has radial power q and periodic angular dependence sin(mφ). The diffraction pattern of ALBs strongly depends on the periodic angular power controlled phase of the DOE. During free-space propagation, the ALBs with different wavelengths convert into different light distributions that have mth-order symmetry (for odd m) and 2mth-order symmetry (for even m). The ALBs exhibit autofocusing properties that significantly differ at longer wavelengths relatively with smaller wavelengths. The formation of light intensity distributions in free-space propagation has a sharp focusing feature that strongly depends on the radial power q. The numerically simulated results are presented for wavelengths in the infrared, visible, and ultra-violet regimes. The experimental findings measured at a wavelength of λ = 1064 nm, show good agreement with the numerically simulated results and thus verifying our approach.

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Section: Discussionmentioning

confidence: 99%

Generating autofocused aberration laser beams with different spectral performance

Reddy

Хонина

Pal

2020

J. Opt.

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“…In addition to this, holographic optical elements, kinoforms which can be used to create customised laser beam profiles, have been studied by Kell et al for laser welding [26], Higginson et al for laser powder bed fusion (L-PBF) [27] and Goffin et al for wire-fed laser cladding [28] and thin-film surface annealing [29]. The majority of these studies focused on metallurgical improvements, however, Goffin et al also found that alterations in the beam profile allowed the creation of wire clad tracks with beam power requirements reduced by 30% for an enlarged gaussian beam and 50% for a square uniform beam.…”

Section: Energy Modelling In Laser Systemsmentioning

confidence: 99%

Characterisation of Laser System Power Draws in Materials Processing

Goffin

Jones

Tyrer

et al. 2020

JMMP

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Due to their high speed and versatility, laser processing systems are now commonplace in many industrial production lines. However, as the need to reduce the environmental impact from the manufacturing industry becomes more urgent, there is the opportunity to evaluate laser processing systems to identify opportunities to improve energy efficiencies and thus reduce their carbon footprint. While other researchers have studied laser processing, the majority of previous work on laser systems has focused on the beam–material interaction, overlooking the whole system viewpoint and the significance of support equipment. In this work, a methodical approach is taken to design a set of energy modelling terminologies and develop a structured power metering system for laser systems. A 300 W fibre laser welding system is used to demonstrate the application of the power characterization system by utilizing a purpose-built power meter. The laser is broken down according to sub-system, with each part analysed separately to give a complete overall power analysis, including all auxiliary units. The results show that the greatest opportunities for efficiency improvements lie in the auxiliary units that support the laser devices as these were responsible for a majority of the electrical draw; 63.1% when the laser was operated at 240 W, and increasing as the beam power reduced. The remaining power draw was largely apportioned to electrical supply inefficiencies. In this work, the laser device delivered a maximum of 6% of the total system power. The implications of these results on laser processing system design are then discussed as is the suitability of the characterization process for use by industry on a range of specific laser processing systems.

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“…Laser polishing differs from more widely known techniques of laser engraving and laser ablation in that it is an equating process, no adding material or removing material as in those techniques. The profile pattern of CW laser beam from the laser generator is Gaussian beam instead of top-hat beam, where the spot is circular but with a uniform intensity profile [7]. A Gaussian beam results in a non-uniform process that polishes some areas of the panel more effectively than others, due to the differences in their thermal cycles.…”

Section: Cw Laser Beam Profile Patternmentioning

confidence: 99%

Experiment Study of Rapid Laser Polishing of Freeform Steel Surface by Dual-Beam

et al. 2019

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One of the challenges regarding widespread use of parts made from alloy steel is their time-consuming polishing process. A rough freeform surface of part has been often expected to be polished rapidly up to a smooth surface finish. The focus of this study is to develop a fast polishing method of freeform surface by using dual-beam lasers. The dual-beam laser system consists of continuous laser (CW) and pulsed laser based on a five-axis CNC device. In this study, a series of experiments of CW laser polishing present the effects of different spot irradiation on surface topography, then the combination trajectory of zigzag and square waveform of pulsed laser is explored to realize a “melting peak for filling into valley” (MPFV) method. The polishing experiment on a semisphere of S136H steel polished by dual-beam shows that a rough semisphere surface was rapidly polished from initial state value of Sa (=877 nm) to post-polished value of Sa (=142 nm), and the polishing efficiency is as high as 2890 cm2/H.

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Complex beam profiles for laser annealing of thin-film CdTe photovoltaics

Cited by 5 publications

References 23 publications

Generating autofocused aberration laser beams with different spectral performance

Generating autofocused aberration laser beams with different spectral performance

Characterisation of Laser System Power Draws in Materials Processing

Experiment Study of Rapid Laser Polishing of Freeform Steel Surface by Dual-Beam

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