The two different configurations for Fourier transform systems are considered. Clearly, the converging beam Fourier transform (CB-FT) setup is simpler than conventional parallel beam setup (PB-FT), and it appears that it should be preferred in ordinary cases. But the advantage of the conventional configuration is to make the Fourier plane free of the spherical factor. In order to obtain an exact Fourier transform, the design of a holographic lens is described with respect to its aberrations.

An analysis of focusing properties of gratings having a constant period and bent to some curvature is given. It has been found that the focusing distance is proportional to the radius of curvature. The arising coma aberration can be compensated for by the gradient of the curvature along the surface of the grating.

In this paper, a close analogy between the theoretical model of forming the profile of a diffractive relief structure in photoresist during development and equations of geometrical optics is shown. It is used for the investigation of evolution of the grating profile arising in a positive photoresist layer which was exposed to the interference field of two laser beams. Verification of theoretical conclusions is based on comparison of theoretical and experimental time dependences of diffraction efficiencies of many orders during development. A SEM photography of the relief of a produced grating sample is presented as well. A short section is devoted to diffraction properties of the structures under study with emphasis on their possible applicability to multiple beam splitting.

Conventional diffractive optical elements with symmetry of revolution like spherical zone plate or axicons are modified by an addition of linear phase change n(theta) along the angular coordinate, where n is a natural number. In consequence of such manipulation the zone borders convert from circles into spirals and the elements modified in this way exhibit a dark dip in the center of the intensity distributions of their diffraction fields, in some cases (e.g. for n equals 1) smaller than the position of the first minimum of the respective distribution of the conventional case. The new family of elements is illustrated by examples of a spiral zone plate as well as spiral linear and logarithmic axicons, and their possible applications in alignment techniques are discussed.

The Light Sword Optical Element (LSOE) is a diffractive structure focusing light into a fragment of the optical axis. An interesting property of the LSOE is its ability for imaging with extended depth of field. Optical Transfer Function (OTF) and Point Spread Function (PSF) are usually applied for description of imaging arrangements. During our investigations several binary phase LSOE structures were fabricated. The structures differ each other with their modulation factor and apertures. A typical main focal length was equal to 74 mm in a case of coherent He-Ne laser illumination of LSOEs. Aperture diameter belonged to the range [2.8 mm, 5.5 mm], the modulation factor varied from 10% to 40% of the main focal length. Each structure was analyzed in the optical system as well as by computer simulation. PSFs of LSOE structures were measured in the optical system and were calculated numerically. Modulated Transfer Functions (MTFs) were calculated on the base of calculated and measured PSFs. Theoretical and experimental results were compared and discussed. Moreover, the experimental and numerical analysis of the Siemens star imaging was performed.

The contribution presents the analytic design of diffractive optical elements focusing light into output curves. The approach is accurate within the scope of the Fresnel diffraction theory and the stationary phase method. The method includes arbitrary focal lines (2D and 3D) parametrized by differentiable functions and different types of holograms (Fourier, Fresnel). The detailed analysis illustrating principles of designing is given for conical diffractive elements.

In (synthetic) holography and diffractive optics, the optical field is often decomposed in a set of spherical or plane waves. This gives sometimes some problems in calculating the Fourier transform. Because Gaussian beams are their own Fourier transform, it seems to be more natural to use Gaussian beams as basis functions. However, because Gaussian functions are no complete set of basis functions, it is necessary to extend the idea and to use rather Gaussian-Hermite wave functions as an orthonormal basis set. Those ideas can also be applied to general Self-Fourier Transform functions.

The goal of this paper is to show the usefulness of various asymptotic formulae in numerical evaluation of the field distribution of divergent spherical wave at the aperture. An example of calculations illustrating the use of these formulae is quoted. The due illustrations are given for the observation point positions, where the respective formulae are valid.

Two novel algorithms for the binarization of continuous rotationally symmetric real positive pupil filters are presented. Both algorithms are based on 1-D error diffusion concept. The original gray-tone apodizer is substituted by a set of transparent and opaque concentric annular zones. Depending on the algorithm the resulting binary mask consists of either equal width or equal area zones. The diffractive behavior of binary filters is evaluated. It is shown that the pupils with equal width zones give Fraunhofer diffraction pattern more similar to that of the original continuous-tone pupil than those with equal area zones, assuming in both cases the same resolution limit of printing device.

Pattern projection is an important application area of diffractive optics, comprising microlithography and laser materials processing. We discuss differences in performance and requirements between pattern projection with conventional imaging optics and with diffractive optics.

A method and experimental setup have been developed for testing the parameters (a pitch, pitch regularity, a gap- to-pitch, amplitude transmission and phase delay) of a periodic microstructure at different stages of fabrication. The method is based on measuring the distribution of light intensity in the diffraction spectrum of a grating. Experimental results on the quality of tracks of a photomask and master grating are presented.

A surface relief holographic grating is designed for the transformation of a Gaussian laser beam into a beam with a flattened plateau in its central part. The depth of grating grooves varies over the surface in order to achieve a distribution of diffraction efficiency complementary to the intensity profile of the laser beam to be transformed. The appropriate efficiency distribution over the grating can be obtained by a technological process during the exposure and development. Experiments have proved that produced grating samples can sufficiently flatten the Gaussian beam, and that the degree of the beam flattening can be easily controlled.

Predictions which are made by the Kirchhoff scalar theory of diffraction are widely used in the diffractive element design but they become unreliable if the diffraction of the polarized light is evaluated. The vector revision of this theory is presented and a novel approach to the diffractive element design is suggested.

Waveguide structure in this context means metallic coated gratings which have periods smaller than the wavelength of the incident light. The grooves of these subwavelength gratings can be regarded as waveguides. Since the phase velocity depends on the groove width of the waveguide, the phase of the reflected light is a function of the duty cycle. By adding waveguides with different duty cycles together, binary lattices can be made which approximate nearly every arbitrary continuous phase function. Examples of these waveguide structures are the so-called artificial dielectrics which act as beam deflector, cylindrical Fresnel zone mirror and Fresnel zone mirror. These elements are presented in this paper.

Peculiarities of variable shaped EBL application to DOE topology generation are regarded. The estimation of exposure data volume is proposed as a function of DOE parameters and approximation accuracy. A special software was developed to prepare DOE's exposure data. Experimental results on topology fabrication are presented for DOE focusing irradiation into a ring with ordered parameters, as well as artificial index gratings.

DEMOS software was designed in the middle of 70-th for noncentering systems design. Main possibilities and examples of program 3 version application for design of optical systems (OS) based on 2-D and 3-D media with nonconventional optical elements, such as holographical and integral optical elements, are discussed in this article.

Third order aberrations of the hybrid (glass-holographic) lenses with spherical and plano-convex surfaces and pupil in contact are considered. The paper includes some analytical results obtained by computer ray tracing method.

Personal computers cause wide use of numerical methods for analysis of optical systems. The very important feature of algorithms applied for this purpose is their time efficiency. A fast algorithm for investigating the image quality of the hybrid lenses (i.e. glass lenses with hologram structure deposited on one of its surfaces) is presented in this paper.

Microlens arrays made in photoresist can be transferred into fused silica substrates by reactive ion etching herby, the etch rates of resist and silica differ by a factor of up to 3 depending on the oxygen content of the reacting gases in the etching machine. The resulting lenses are tested for the surface quality with the help of a Mach- Zehnder interference microscope. Merit functions such as point spread function and modulation transfer function can be calculated from the measured wave aberration data.

Silver aluminum phosphate glassed have been tested as a material for gradient index (GRIN) elements fabrication by exchange of Na⁺ ions from mixed molten salt baths by the Ag⁺ ones. The annealing technique was used to control the final gradient and GRIN rod elements with radial index profile were prepared with n(r) equals n_o(1 - A/2 (DOT) rⁿ) where 2 1/2 is congruent to 0.075. The calculated longitudinal aberration was smaller then 5 micrometers within the region of 50% radius from axis.

In recent 25 years a new kind of optical elements - gradient-index lenses, especially these of SELFOC type - meet with wide applications in many devices (photocopiers, compact disc players). Regardless of used in manufacturing of these lenses kind of technology, the nonuniformity of material (different doping concentration) and differences between the coefficients of linear expansion in the particular regions of the lens causes the internal stresses. Due to these stresses the gradient-index lens have to be considered as a birefringent medium. Anisotropy evoked by these stresses causes the splitting of the incident wavefront into two orthogonally polarized wavefronts and as a result: changing the image quality. The results of measurements of internal stresses and anisotropy for a few lenses are shown. The estimation of the split of the ordinary and extraordinary rays in these lenses and the numerical investigation of their diffraction image quality are presented.

This method is proposed for determination of Modulation Transfer Function (MTF) of a single GRIN rod with symmetrical spread function. Central irradiencies are measured in the image of a variable slit and MTF is calculated with the use of the results of these measurements according to the suggested formula with computer processing. The device is remarkable for its simplicity for MTF measurements.

The surface emission effects are investigated for optical waveguides, formed on the basis of K8 glass with a low temperature ion exchange treatment. As a result of the experiments performed it is proved the possibility of exciting nonstationary electron emission from the surface of gradient planar waveguides under the action of intrinsic radiation of the waveguide. The emission selection effect for guide wave modes is discover. It consists of electron-emission mode spectrum dependence on preliminary excitation of fixed order mode.

Gradient indices are enjoying great interest these days. The glass rods with a continuous variation of refractive index are currently used for lens systems for compact copiers, compact audio/video disc, and are expected to be applied in the near future to the more complicated systems such as cameras, binoculars, microscopes an so on. The biggest change of the glass surface can be obtained exposing the glass for the ion exchange process. When a glass slab is put into contact with a molten salt, cations of the molten salt can exchange with ions existing at the glass surface, and then the exchanged ions will migrate into the glass with in turn may change in the structure, or new ions may be different in size in polarizability and induce strains in the glass in turn may change the index. The refractive index profile depends upon the composition of the initial glass as well as the condition of ion exchange technological process. In this work 8 types silicate glass has been investigated by optical stimulation exoemission electrons. This method is sensitive for the way of preparation of the samples. Basing on this performing investigations of the physical properties of the glass before the ion exchange we propose the recommendations concerning correlation of the composition of the initial glass and optimal technological conditions of the gradient lenses production.

The paper describes a new type of optical element, combining the properties of the deflector and the lens. The idea of the new element is to change electrooptically the wave front of light the same way as the classical lens does. In other words, the new lens will focus the light like usual lens. The simplest construction of variable focus lens is almost identical to prism-type deflector except but parabolic profile of slit between the upper electrodes. Changing the electrical voltage, connected to the two half of parabolically cut electrode, on will change the point of focusing, so the focus distance of such lens will be electrically changed. The evaluation shows that volume type of variable focus lens can be realized with modern high effective electrooptical materials. Much more effective operating such lens can be realized in waveguide variant.

Nonconventional optical imaging elements as holograms, caused some crucial changes in architectural theory and practice. Architecture using holograms on the facade skin can be divided into parallel and interconnective architecture. Using H.O.E.s and C.G.H.s in a special way, we can talk about third architecture which is not (necessary) bounded to any of known architectural and aesthetical standards, an 'enfant perdu' which penetrates in the very systems of architecture.

Holographic optical lens elements (HOEs) are volume grating in thick material such as dichromated gelatine (DCG) which suffer from the wavelength mismatch between the recording process and the practical application e.g., at laser diode wavelengths. Wavelength mismatch between recording and reconstruction is caused by the fact that the best recording materials are sensitive only in the blue region of the spectrum. The advantage of volume gratings (thickness 13 micrometers ) is the large angle of deflection of the first diffraction order with a high diffraction efficiency. An optimized recording geometry using only spherical wave fronts allows on the one hand for the elimination of one of the third order aberrations (predominantly: astigmatism) or on the other hand for the fulfillment of the Bragg condition. To optimize the properties of holographic optical lens elements with one aspheric recording wave a kind of iterative procedure for the manufacturing is proposed. Each iteration consists of three different steps.