Holography can store wavefields in light-sensitive material. Due to its flexibility and the potential of multiplexing several functions into one element, holography has also been proposed as a recording technique for micro-optical elements. This paper discusses the recording of holograms that perform the basic functionalities (deflection, focusing, and fan-out) needed in micro-optical systems. Emphasis is given to the optimum recording of fan-out elements and high-density multifacet holograms. Successful recording schemes are presented, which are easy to align and therefore are interesting for the fabrication of systems. The potential of holography is demonstrated by recording 10,000 lenslets on 1 cm(2) in a compact optical system. in addition, several highly efficient fan-out elements have been recorded as volume and surface-relief holograms.

We report preliminary experimental results on the use of a filter with a parabolic transmission profile for a direct measurement of the spatial variance of the intensity distribution of a laser beam. It is shown that by recording, at various planes, the maximum transmitted power through such a filter, one can characterize the beam without having to determine the corresponding intensity profiles. A simple parabolic fit of the data allows the determination of the required parameters for a second-moment-based beam characterization.

Interferometric recording is applied to the fabrication of modulated submicrometer gratings in photoresist.High diffraction efficiency requires optimized recording conditions, which are obtained by the use of an on-axis continuous surface-relief grating for the generation of the object beam. The optimized phase function is copied into the resist layer by means of a self-aligned two-step recording process with an intermediate copy in a volume photopolymer hologram. As a result, we demonstrate high carrier frequency surface-relief off-axis fan-out gratings for illumination in transmission with visible light.

We investigated two optical methods for characterizing submicron structures. Average errors of a few nanometers can be determined by the far-field diffraction metrology utilizing diffractive structures having enhanced sensitivity to fabrication errors. The scanning spot metrology is well suited for analyzing lithographic masks.

Total internal reflection (TIR) holographic lithography is applied to the fabrication of binary diffractive optical elements with submicrometer surface relief features. The recording conditions for the intermediate TIR volume hologram, used for high-resolution proximity printing, are discussed. In particular, the fabrication of efficient high-carrier-frequency fan-out gratings is considered and experimental results are presented for an off-axis 9 x 1 fan-out element in photoresist with a carrier frequency of 1000 lines/mm.

The fabrication of diffractive optical elements by laser-beam writing or gray-tone technology leads to continuous-relief phase elements. The diffraction efficiency of such elements is limited by the resolution of the process. In this paper, we compare the continuous-relief elements with the multilevel elements fabricated by binary technology. In particular, we will show that for similar sampling resolution of the ideal phase function, the continuous profiles have higher efficiencies than the multilevel profiles if the designed phase modulation is 4π and more.

The design of kinoform fan-out elements with high efficiency and reduced sensitivity to vertical profile scaling errors is presented, We start from a high-efficiency continuous-phase fan-out solution and optimize the position of the 0-2 pi transitions in the phase function, in order to achieve a high fabrication-error tolerance. The sensitivity of Fourier-transform and focusing fan-out elements to vertical etch-depth errors is analyzed. The limitations for the fabrication of such structures by laser-beam writing are discussed, In particular, the influence of the finite writing-spot diameter on the fan-out performance is investigated. Design rules for fan-out elements, which consider fabrication constraints, are derived, Experimental results are presented for cylindrical focusing fanout elements With Small uniformity error (2%) and weak profile scaling dependence.

An electrically switchable diffractive optical element has been built based on a computer-generated phase hologram and a liquid-crystal layer. The design of the diffractive optical element and the fabrication and performance of the device are discussed. The application of the device in a machine vision system for optical surface inspection is shown.

The paper investigates the recording of efficient off-axis fan-out elements for optical interconnections. The analysis of fan-out elements recorded in volume holograms (coupled wave theory) shows that high efficiency (>90%) and uniformity can be achieved by simultaneous and sequential recording of N object beams. Experimentally, we have achieved 94% efficiency (uniformity error ±5%). The maximum number of fan-out beams and the full fan-out angle are limited by the thickness and by the dynamic range of the holographic emulsion. Optimized recording conditions enable also the realization of high-frequency surface-relief gratings in photoresist which can then be transformed into other materials, like quartz

An electrically switchable hologram has been built based on a computer generated phase hologram and using a liquid crystal (LC) layer. The optical influence of the device can be controlled by varying an applied electrical field. The fabrication and performance of the hologram is discussed

For practical applications of optical measuring devices designers have to take into consideration compactness, low weight and low price. Conventional optical systems are normaly not optimized with respect to these requirements. Computer generated optical elements allow an integration of different functions into one single element as well as a cheap duplication. In this paper we report on experimental results of some examples of computer generated optical elements like phase plates, and polarisers which are used in interferometrical and holographical devices. Transmission and reflection holograms can be realized with high efficiency and low scattering.

Laser diode arrays (LDAs) can generate coherent light beams of high power. Unfortunately, LDAs generate poor quality output beams, which cannot be properly collimated by conventional diode laser optics. In order to improve the optical quality of the output, Veldkamp et al. [1] have proposed different possibilities using binary optical elements. Our approach is based on the tandem component described in Ref. 2 , but it uses a simple phase plate and a continuous surface relief-element for the fan-in of the N beams. Theory for the design and the realization of the diffractive optical elements (DOEs), simulated results for the performance of the system, as well as experimental results for a compact set-up will be presented.