Performance of various holographic techniques can be essentially improved by homogenizing the intensity profile of the
laser beam with using beam shaping optics, for example, the achromatic field mapping refractive beam shapers like
πShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to
flattop one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low
divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design
provides capability to work with several laser sources with different wavelengths simultaneously. Applying of these
beam shapers brings serious benefits to the Spatial Light Modulator based techniques like Computer Generated
Holography or Dot-Matrix mastering of security holograms since uniform illumination of an SLM allows simplifying
mathematical calculations and increasing predictability and reliability of the imaging results. Another example is multicolour
Denisyuk holography when the achromatic πShaper provides uniform illumination of a field at various
This paper will describe some design basics of the field mapping refractive beam shapers and optical layouts of their
applying in holographic systems. Examples of real implementations and experimental results will be presented as well.
Refractive beam shapers of the field mapping type find use in various industrial, scientific and medical applications,
where generation of a collimated beam of uniform intensity is required. Due to their unique features, such as: low output
divergence, high transmittance and flatness of output beam profile and extended depth of field, refractive field mappers
may also be successfully used in combination with beam shaping optics of other operational principles. This combining
makes it possible to improve drastically the performance of these beam shaping techniques.
For example, the non-uniformity of the beam profile of many lasers leads to complexity and inconvenience in various
beam shaping techniques based on applying spatial light modulators (SLM). Applications include Computer Generated
Holography (CGH), holographic projection processing applications, holographic lithography, optical trapping and laser
illumination in confocal microscopes. With a collimated flattop beam provided by refractive field mappers these
techniques become easier to use, more effective and reliable in operation.
This paper will describe some design basics of refractive beam shapers of the field mapping type, with emphasis on the
features important for applications with SLMs. There will be presented comparative results of applying the refractive
beam shapers in systems of holographic lithography and other techniques.
Different scientific and industrial laser techniques require not only intensity profile transformation but also creating
various shapes of final spots like circles of different diameter, lines and others. As a solution it is suggested to apply
combined optical systems consisting of a refractive beam shaper of field mapping type providing a required intensity
transformation and additional optical components to vary the shape of final spots. The said beam shapers produce low
divergence collimated flattop beam that makes it easy to vary the shape of the beam spot with using either ordinary relay
imaging optics, including zoom one, or anamorphotic optics. And the design features of the refractive beam shapers
allow controlling the intensity distribution in the final spot (most often flattop one) and providing wide range of spot
sizes. This paper will describe some design examples of combined beam shaping systems to create round spots of
variable diameter as well as linear spots of uniform intensity. There will be presented results of applying these systems in
such applications as laser hardening and others.
We describe a technique whereby photolithography has been extended to the patterning of near micron-scale features
onto grossly non-planar substrates. Examples will be given of track widths down to ten microns patterned over surfaces
with vertical dimensions in excess of one centimetre - far outside the normal bounds of photolithography. The technique
enables many novel microsystem packaging schemes and provides an alternative to the direct-write methods that are
traditionally employed for patterning non-planar surfaces. The technique is based on the computation of the
phase/amplitude distribution on the mask that, when illuminated with light of sufficient spatial coherence, will recreate
the desired non-planar light distribution. This has some similarities to existing RET and inverse lithography techniques,
but is extended to grossly non-planar surfaces. Exposure of an electrophoretic photoresist-coated substrate to the light
field created by the mask enables the non-planar pattern to be transferred to the substrate. The holographic mask contains
localized Fresnel patterns. We discuss the analytical methods used for their computation, the approximations necessary
to enable mask manufacture and the effects of these approximations on image quality. We also discuss more general numerical methods of mask computation.
We demonstrate the direct photolithographic patterning of a grossly nonplanar substrate by creating 62-µm helical tracks on a 22-mm-high cone. The projection of focused light onto the 3-D surface is achieved using a computer-generated hologram (CGH) suitably illuminated so as to create the required pattern on the photoresist-coated surface. The approach adopted forms the basis of a novel method for patterning nonplanar structures. We address the key challenges encountered for the implementation of holographic photolithography in three dimensions, including mask design and manufacture, exposure compensation, mask alignment, and chemical processing. Control of linewidth and resolution over the nonplanar surface is critical. We describe the methods adopted and critically assess the structures created by this process. The bihelical cone is representative of a broadband, high-frequency coil-like structure, known in wireless communications as a log-periodic antenna.