Alexander Laskin

Bio: Alexander Laskin is an academic researcher. The author has contributed to research in topics: Laser beam quality & Laser. The author has an hindex of 9, co-authored 57 publications receiving 349 citations.

Achromatic refractive beam shaping optics for broad spectrum laser applications

Abstract: The task of providing the same conditions of intensity profile transformation for a broad spectral bandwidth can be solved by refractive beam shaping optics with achromatic design. This solution is important for various scientific and industrial applications including confocal microscopy, biomedical fluorescence techniques, some industrial technologies and many tasks based on short pulse lasers where a bandwidth of up to hundreds of nm is to be provided. The design of achromatic refractive beam shapers is based on applying of materials of different dispersion characteristics and provides necessary intensity distribution transformation simultaneously for laser beams in wide spectral range. These achromatic beam shapers keep the resulting intensity distribution over a long distance, operate with collimated and divergent beams and provide easy adaptation to specifications of real lasers. This paper will describe some design examples of achromatic beam shapers optimized to be used with short pulse lasers like Ti:Sapphire or Yb:KGW ones in infrared and ultraviolet spectrum. There will be presented results of applying achromatic laser beam shapers with short pulse lasers in such applications as irradiating the cathode of Free Electron Lasers, processing of photovoltaic materials.

Variable beam shaping with using the same field mapping refractive beam shaper

Abstract: Modern laser scientific techniques and industrial technologies require not only simple homogenizing of a beam but also more freedom in manipulation of intensity profile and generating such profiles like super-Gaussian, inverse-Gaussian, skewed flattop and others. In many cases the task of variable beam shaping can be solved by refractive beam shaping optics of field mapping type which operational principle presumes saving of beam consistency, providing collimated output beam of low divergence, high transmittance and flatness of output beam profile, extended depth of field; another important feature is negligible residual wave aberration. Typically the fields mapping refractive beam shapers, like πShaper, are designed to generate flattop intensity profile for a beam of pre-determined size and input intensity profile. Varying of the input beam diameter lets it possible to realize either super-Gaussian (smaller input) or inverse-Gaussian (bigger input) intensity profiles of output beam that are important in pumping of solid-state lasers, hardening, cladding and other techniques. By lateral shift of a beam with respect to a πShaper the output flattop profile gets a skew in direction of that shift, the skew angle corresponds to the shift value. The skewed profile is important, for example, in some acousto-optical techniques where compensation of acoustic wave attenuation is required. All variety of profiles can be provided by the same beam shaper unit. This paper will describe some design basics of refractive beam shapers of the field mapping type and techniques to vary the output intensity profile, experimental results will be presented as well.

Imaging techniques with refractive beam shaping optics

Abstract: Applying of the refractive beam shapers in real research optical setups as well as in industrial installations requires very often manipulation of a final laser spot size. In many cases this task can be easily solved by using various imaging optical layouts presuming creating an image of a beam shaper output aperture. Due to the unique features of the refractive beam shapers of field mapping type, like flat wave front and low divergence of the collimated resulting beam with flattop or another intensity profile, there is a freedom in building of various imaging systems with using ordinary optical components, including off-the-shelf ones. There will be considered optical layouts providing high, up to 1/200×, de-magnifying factors, combining of refractive beam shapers like πShaper with scanning systems, building of relay imaging systems with extended depth of field. These optical layouts are widely used in such laser technologies like drilling holes in PCB, welding, various micromachining techniques with galvo-mirror scanning, interferometry and holography, various SLM-based applications. Examples of real implementations and experimental results will be presented as well.

Applying of refractive spatial beam shapers with scanning optics

Abstract: Using of refractive beam shapers with laser scanning optics is often considered in realizing various industrial laser technologies as well as techniques used in scientific and medical applications. Today the galvo mirror scanners with F-theta, telecentric or other lenses as well as gantry systems are widely used in different applications like micromachining, solar cell manufacturing, microwelding, drilling holes, selective laser melting and others which performance can be improved by applying of beam shaping optics. And, due to unique features like low output beam divergence, high transmittance as well as extended depth of field and capability to generate various beam profiles, the refractive field mappers provide a freedom in building an optimum optical system. There will be considered some basic theoretical features of choosing an optimum refractive beam shaper and building systems on its base, as well as several optical layouts with beam shapers πShaper to generate laser spots of uniform intensity which sizes span from several tens of microns to millimetres. Examples of real implementations will be presented as well.Using of refractive beam shapers with laser scanning optics is often considered in realizing various industrial laser technologies as well as techniques used in scientific and medical applications. Today the galvo mirror scanners with F-theta, telecentric or other lenses as well as gantry systems are widely used in different applications like micromachining, solar cell manufacturing, microwelding, drilling holes, selective laser melting and others which performance can be improved by applying of beam shaping optics. And, due to unique features like low output beam divergence, high transmittance as well as extended depth of field and capability to generate various beam profiles, the refractive field mappers provide a freedom in building an optimum optical system. There will be considered some basic theoretical features of choosing an optimum refractive beam shaper and building systems on its base, as well as several optical layouts with beam shapers πShaper to generate laser spots of uniform intensity whic...

Applying of refractive beam shapers of circular symmetry to generate non-circular shapes of homogenized laser beams

Abstract: Creating of non-circular laser spots, for example of linear, elliptical or rectangle shape, with uniform intensity profile is important in various laser techniques in industry, scientific and medical applications. This task can be successfully solved with applying of refractive beam shaping optics of field mapping type in combination with some additional optical components. Due to their unique features, such as: low output divergence, high transmittance and flatness of output beam profile as well as extended depth of field, the refractive field mappers provide a freedom in further manipulation with intensity profile and shape of a laser beam. Typically design of refractive field mapping beam shapers has circular symmetry; therefore creating of non-circular spot shapes requires applying anamorphic optical components (cylinder lenses, prism pairs, etc.) ahead of or after a beam shaper. As result it becomes possible to provide various combinations of spot shape and intensity profiles, for example: roof-like spot with uniform intensity in one direction and Gaussian or triangle profile in another direction, linear spots with aspect ratio up to 1:1000, elliptical spots of uniform intensity, etc. Applications include flow cytometry instrumentation, particle image velocimetry, particle size analyzing, hardening, cladding, annealing, and others. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts for creating laser spots of non-circular symmetry. Examples of real implementations will be presented as well.

Variable beam shaping with using the same field mapping refractive beam shaper

Abstract: Modern laser scientific techniques and industrial technologies require not only simple homogenizing of a beam but also more freedom in manipulation of intensity profile and generating such profiles like super-Gaussian, inverse-Gaussian, skewed flattop and others. In many cases the task of variable beam shaping can be solved by refractive beam shaping optics of field mapping type which operational principle presumes saving of beam consistency, providing collimated output beam of low divergence, high transmittance and flatness of output beam profile, extended depth of field; another important feature is negligible residual wave aberration. Typically the fields mapping refractive beam shapers, like πShaper, are designed to generate flattop intensity profile for a beam of pre-determined size and input intensity profile. Varying of the input beam diameter lets it possible to realize either super-Gaussian (smaller input) or inverse-Gaussian (bigger input) intensity profiles of output beam that are important in pumping of solid-state lasers, hardening, cladding and other techniques. By lateral shift of a beam with respect to a πShaper the output flattop profile gets a skew in direction of that shift, the skew angle corresponds to the shift value. The skewed profile is important, for example, in some acousto-optical techniques where compensation of acoustic wave attenuation is required. All variety of profiles can be provided by the same beam shaper unit. This paper will describe some design basics of refractive beam shapers of the field mapping type and techniques to vary the output intensity profile, experimental results will be presented as well.