Multifunctional micro-optical elements for laser beam homogenizing and beam shaping

Bich, A.; Rieck, J.; Dumouchel, Christine; Roth, S.; Weible, K. J.; Eisner, Martin; Voelkel, Reinhard; Zimmermann, Maik; Rank, Manuel; Schmidt, Michael; Bitterli, R.; Ramanan, N.; Ruffieux, Patrick; Scharf, Toralf; Noell, Wilfried; Herzig, Hans Peter; Rooij, Nico de

doi:10.1117/12.762923

Cited by 18 publications

(6 citation statements)

References 9 publications

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“…Uniform irradiance in the mask plane is achieved using an imaging microlens array (MLA) homogenizer as a Köhler integrator, i.e., a combination of two MLAs and a Fourier lens [34]. In comparison to a previous approach using a diffractive non-imaging homogenizer [9], we demonstrate here a clear improvement with regard to field uniformity and light efficiency [33].…”

Section: Optical Setup and Beam Shapingmentioning

confidence: 79%

Printing sub-micron structures using Talbot mask-aligner lithography with a 193 nm CW laser light source

Vetter¹,

Kirner²,

Opalevs³

et al. 2018

Opt. Express

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A continuous improvement of resolution in mask-aligner lithography is sought after to meet the requirements of an ever decreasing minimum feature size in back-end processes. For periodic structures, utilizing the Talbot effect for lithography has emerged as a viable path. Here, by combining the Talbot effect with a continuous wave laser source emitting at 193 nm, we demonstrate successfully the fabrication of periodic arrays in silicon substrates with sub-micron feature sizes. The excellent coherence and the superior brilliance of this light source, compared to more traditional mercury lamps and excimer lasers as light source, enables the efficient beam shaping and a reduced minimum feature size at a fixed gap of 20 µm. We present a comprehensive study of proximity printing with this system, including simulations and selected experimental results of prints in up to the fourth Talbot plane. This printing technology can be used to manufacture optical metasurfaces, bio-sensor arrays, membranes, or microchannel plates.

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Section: Optical Setup and Beam Shapingmentioning

confidence: 79%

Printing sub-micron structures using Talbot mask-aligner lithography with a 193 nm CW laser light source

Vetter¹,

Kirner²,

Opalevs³

et al. 2018

Opt. Express

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“…To minimize spreading, we must synchronize the generation of local channels by equalizing the W PUMP over laser aperture. With this purpose and for the elimination of possible damage to the Ti:Sapphire crystal by hot spots in the 532 nm beam, we arranged pump beam homogenization using two-dimensional microlens array (MLA) [21], as shown in Figure 4. After the homogenization, we obtained the stable generation of single pulses.…”

Section: The Characteristics Of Short Cavity Ti:sapphire Gain-switched Laser Under Nanosecond Pumpingmentioning

confidence: 99%

Engineering of Ti:Sapphire Lasers for Dermatology and Aesthetic Medicine

Tarasov¹,

Chu²

2021

Applied Sciences

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This review describes new engineering solutions for Ti:Sapphire lasers obtained at Laseroptek during the development of laser devices for dermatology and aesthetic medicine. The first device, PALLAS, produces 311 nm radiation by the third harmonic generation of a Ti:Sapphire laser, which possesses similar characteristics to excimer laser-based medical devices for skin treatments. In comparison to excimer lasers, Ti:Sapphire laser services are less expensive, which can save ~10% per year for customers compared to initial excimer laser costs. Here, the required characteristics were obtained due to the application of a new type of diffraction grating for spectral selection. The second device, HELIOS-4, based on the Ti:Sapphire laser, produces 300 mJ, 0.5 ns pulses at 785 nm for tattoo removal. The characteristics of HELIOS-4 exceed those of other tattoo removal laser devices represented in the medical market, despite a simple and inexpensive technical solution. The development of the last laser required the detailed study of a generation process and the investigation of the factors responsible for the synchronization of the generation in Ti:Sapphire lasers with short (several millimeters) cavities. The mechanism that can explain the synchronization in such lasers is suggested. Experiments for the confirmation of this concept are conducted and analyzed.

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“…Exceeding the acceptance angle leads to power loss and cross talking between the lenses. The allowed maximum angle σ1 for a single micro lens is (6). The maximum angle for the complete micro lens array is…”

Section: Multi Spot Generation With Fly's Eye Condensermentioning

confidence: 99%

“…In the field of laser materials processing, optical measuring technology, biotechnology and medicine [3] many new applications for efficient array generators can be found. A number of optical systems and elements, such as spatial light modulators (SLM) [4], diffractive optical elements (DOE) [5] or micro lens arrays (MLA) [6,7,8] have been examined for generation of multiple spot arrays for laser micro machining applications.…”

Section: Introductionmentioning

confidence: 99%

Combination of a micro-lens multi-spot generator with a galvanometer scanner for flexible parallel micromachining of silicon

Zimmermann

Schmidt

2011

SPIE Proceedings

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Multi focus optics are used for parallelizing production and for large-scale material processing. These elements split the beam into a periodic spot pattern with a defined grid and spot size. The challenge lies in the generation of a homogeneous envelope. Additionally the demand for flexible systems for an in-process changing of optical properties increases. Different components for multi spot generation like diffractive optical elements or micro lens arrays have been investigated. Diffractive optical elements offer large degree of freedom in the generation of arbitrary intensity distributions. In the paper we demonstrate the use of a diffractive element in combination with a multi spot generator.Within the paper we present the investigation of a micro lens array in a fly's eye condenser setup for the generation of homogeneous spot patterns. The multi spot generator is combined with a galvanometer scanner for forming an arbitrary shaped laser beam into a spot-, ring or arbitrary array pattern. We show the principal functionality of the multi-spot generator. Furthermore constrains of this setup are demonstrated. The multi spot scanner is used for micro structuring of silicon with a nanosecond diode pumped solid state laser. The ablation rate and structure quality are compared to single spot processing. IntroductionThe ongoing development of new laser sources with a continual increase in laser power enables higher production speeds for example in the application of micro machining, hole drilling or perforation. The processing speed however is still limited by the maximum speed of positioning systems. State-of-the-art laser systems provide high pulse energies which normally exceed the laser ablation threshold energy density by several orders of magnitude. Additionally the ablation quality decreases with increasing energy density clearly over the ablation threshold. In this case energy is wasted which leads to a decrease in the throughput and efficiency. Parallelizing a laser process can increase the throughput of the production. This can be done with a so-called array generator, an optical system that splits a light beam in a 1 -or 2-dimensional array of beamlets [1,2]. In the field of laser materials processing, optical measuring technology, biotechnology and medicine [3] many new applications for efficient array generators can be found. A number of optical systems and elements, such as spatial light modulators (SLM) [4], diffractive optical elements (DOE) [5] or micro lens arrays (MLA) [6,7,8] have been examined for generation of multiple spot arrays for laser micro machining applications.

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Multifunctional micro-optical elements for laser beam homogenizing and beam shaping

Cited by 18 publications

References 9 publications

Printing sub-micron structures using Talbot mask-aligner lithography with a 193 nm CW laser light source

Printing sub-micron structures using Talbot mask-aligner lithography with a 193 nm CW laser light source

Engineering of Ti:Sapphire Lasers for Dermatology and Aesthetic Medicine

Combination of a micro-lens multi-spot generator with a galvanometer scanner for flexible parallel micromachining of silicon

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