FABRICATION OF METAL MICRONEEDLE BASED ON LASER ABLATION USING TWISTED LIGHT WITH SPINSCPY491 Undergraduate Physics Seminar 21 September 2021st

Natwadee Sarapong 6105161, 4 year undergraduate student, Department of Physics, Faculty of Science, Mahidol University

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Faculty of Science

https://www.chula.ac.th/en/news/12824/

Introduction

Methodology

Results and Discussion

Conclusion

OUTLINES- What is microneedle - Laser ablation

- Twisted light with spin - Experimental Set Up

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Microneedles are the technique of transdermal drug delivery which are ;

- pain free

- no damaging blood vessels

- higher weights of drug

- drug delivery with differing features

Suh H, et al., 2014

INTRODUCTION

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WHAT IS MICRONEEDLE ?

INTRODUCTION

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There are several type of microneedles ; solid removable, dissolving, holow, hydrogel-forming and coated microneedles

Rzhevskiy, A.S., et al., 2018

Laser ablation is a promising top-down process for material precessing by irradiating it with laser beam.

INTRODUCTION

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LASER ABLATION

For example:

- Microdrilling - Cutting - Scribing

- Metals - Dielectric materials - Semiconductors

into

INTRODUCTION

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LASER ABLATION

- Energy is first transferred to the electron system, and then to the lattice system.

- Its temperature increases phase transition occurs from solid state to liquid, gaseous, and plasma states

- Phase transition occurs from solid state to plasma states

Preparation of nanoparticles by laser in solution https://en.wikipedia.org/wiki/Laser_ablation

INTRODUCTION

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LASER ABLATION At high laser flux, the material is typically converted to a plasma.

- pulsed laser

- continuous wave laser with high intensity

Wavelength of laser is approximately 200nm

HIGH COST

Types of laser that can contribute the ablation :

Preparation of nanoparticles by laser in solution https://en.wikipedia.org/wiki/Laser_ablation

The surface processed using twisted light caused less debris in comparison with one using untwisted annular nanosecond pulses.

INTRODUCTION

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LASER ABLATION

Consider the laser pulse…

Normal laser twisted laser (helical wavefront) : nanosecond optical vortex pulses

with orbital angular momentum (L) and an annular intensity in the transverse plane

LOWER COST

A total angular momentum (J) equal to the vector sum of the orbital (L) and spin (S) angular momentum.

The direction of the vortex with L = 1 is the same as the circular polarization,

The opposite direction contributes

|J | = |L | + |S | = 2

|J | = |L | − |S | = 0

METHODOLOGY

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Definition of the total angular momentum of twisted light with spin.

METHODOLOGY

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Experimental Set UpMetal laser ablation using nanosecond optical vortex pulses with orbital angular momentum was performed.

Equipments:

- SPP : spiral phase plate - QWP : quarter-wave plate - ~1 mm thick tantalum plate

Why Ta?Ta has low ablation threshold in comparison with other metals, which makes the ablation become easier.

METHODOLOGY

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Experimental Set Up>> How the needle is formed?

Model for a microneedle fabrication by 'twisted-light with spin' laser ablation

RESULTS

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Laser-scanning microscope images of processed surfaces pumped by

twisted light

a protuberance appears at the center of the processed surface

Debris caused by plasma spin

RESULTS

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Experimental data obtained for a total angular momentum of 2

RESULTS

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Experimental data obtained for a total angular momentum of 2

{Ratio of the length of the protuberance to its thickness}

RESULTS

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Fabrication of a two-dimensional 5 × 6 microneedle array by twisted-light laser ablation, using 2 twisted light pulses

Average length = 11 μm

Tip diameter = 0.5 μm

The standard deviations in the length and tip diameter are estimated to be 1.9 and 0.15 μm, respectively.

CONCLUSION

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Two-dimensional microneedle arrays fabrication >>> All needles have uniformly good quality.

This method contributes high-speed nano-imaging, energy-saving displays.

demonstration of microneedle fabrication using laser ablation by nanosecond twisted light with spin

Comparing the total angular momentum of J = 2 and J = 0, J = 0 gives better results that:

- higher aspect ratio

- less debris

demonstration of microneedle fabrication using laser ablation by nanosecond twisted light with spin

Using J = 2 twisted light with spin and observing the resulting of pulses number

“there is the optimal shots (around 3-4 shots)”

REFERENCES

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Takashige Omatsu, Keisuke Chujo, Katsuhiko Miyamoto, Masahito Okida, Kazuki Nakamura, Nobuyuki Aoki, and Ryuji Morita, "Metal microneedle fabrication using twisted light with spin," Opt. Express 18, 17967-17973 (2010)

Junichi Hamazaki, Ryuji Morita, Keisuke Chujo, Yusuke Kobayashi, Satoshi Tanda, and Takashige Omatsu, "Optical-vortex laser ablation," Opt. Express 18, 2144-2151 (2010)

Hongkun Huang, Jiancheng Lai, Jian Lu, and Zhenhua Li , "Pulsed laser ablation of bulk target and particle products in liquid for nanomaterial fabrication", AIP Advances 9, 015307 (2019) https://doi.org/10.1063/1.5082695

Q&A