Jerzy Krezel

Phase manipulation and optoelectronic reconstruction of digital holograms by means of LCOS spatial light modulator

Fresnel and Fourier holograms recorded by CCD/CMOS cameras can be numerically or optoelectronically reconstructed in order to provide visualization of 3D objects or to enable further manipulation of their phases and amplitudes. In the paper we propose to introduce into digital holographic (DH) setup Liquid Crystal on Silicon (LCOS) spatial light modulator as an active 2D optoelectronic element which facilitates performing a variety of operations at the recording and reconstruction stages. This includes introducing phase shifting digital holography, additional phase manipulation for object contouring and displacement measurements as well as for optoelectronic reconstruction of all types of digital holograms. The results of initial experiments performed with LCOS are presented and discussed. Also the future directions of development of active DH and DHI system are outlined.

Towards integration of glass microlens with silicon comb-drive X-Y microstage

We present the design and the fabrication of a silicon X-Y microstage and a new concept of its integration with a glass microlens to obtain an optical 2D scanner for the miniaturized microscope on-chip.

Design and testing of a low-cost full-field integrated optical extensometer

The paper deals with design and implementation of an optical extensometer based on grating (moire) interferometry, for large engineering construction monitoring. The paper presents the principles of the grating interferometry and the construction of miniaturized and portable version of grating interferometer and its implementation for out-door measurement directly at civil engineering structures. The paper presents also a concept of the low-cost full-field optical extensometer.

Laser waveguide microinterferometer integrated with MEMS platforms

Recent growth of micro and nano technology offers large variety of micro scale devices, which gradually replace bulk appliances of everyday use. MEMS devices are being used in medical, science research, military and industrial applications. Since their technology is not fully mastered yet, they require special measurement treatment from stage of production to stage of utilization. Most of nowadays used bulk measurement instrumentation require special preparation of MEMS element to test (putting elements on special stages or combining MEMS devices with cheap and simple instrumentation (fiber sensors)). Since MEMS technology is meant to be inexpensive a trend of building MEMS measurement instrumentation for nano and micro elements testing appeared. In this paper we present the concept of novel multifunctional waveguide interferometer for three components of displacement vector measurement of elements with optical or rough surfaces. The measurement system combines the various techniques: conventional Twyman-Green (TGI), grating (moire) interferometry (GI), ESPI and digital holographic interferometry (DHI). It consists of several modules such as light source and detector integrated module, passive interferometric module, waveguide interferometer head and MEMS based active beam manipulators. The proposed design of modules decrease significantly their sensitivity to vibration, so that they can work in instable environment.

M(O)EMS-based integrated micro-interferometric system

In the paper idea of integrated waveguide micro-interferometric system is presented. Results of numerical simulation of beam propagation (geometrical and wave depiction) in the measurement interferometric module is presented. Article also briefly presents laboratory setups, which are used to model the interferometers.

The C3PO project: a laser communication system concept for small satellites

The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO1 system, “advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects”, and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.

Technology chain for production of low-cost high aspect ratio optical structures

The paper covers the studies on the replication process of the high aspect ratio optical structures performed by Hot Embossing technology. Considered structures are the microinterferometric heads shaped in the form of PMMA blocks with a high frequency diffraction grating placed on the side walls. We propose the full technology chain including replication of the glass machined prototypes. Additionally the preliminary characterization tests of exemplary replicated optical structures are presented.

Modified linear and circular carrier-frequency Fourier-transform method applied for studies of vibrating microelements

Stroboscopic interferometry is the most popular method for investigation of active, vibrating elements. The interferograms obtained in measurement steps may be analysed by temporal phase shifting method or by spatial carrier frequency methods. The first one requires sequential capturing of phase-shifted interferograms which complicates the measurement system and introduces high stability requirements for the setup. The spatial methods need a single interferogram with a proper spatial carrier frequency (SCF), so they are more suitable for dynamic events analysis. The most frequently used spatial method is based on Fourier transform of an interferogram with linear SCF and can be applied to analysis of restricted class of elements represented by quasi-linear fringes. This can be easily expanded by considering elements with circular carrier fringes (CCF). In the paper two approaches to analysis of interferograms with CCF, namely: coordinate transform Fourier transform technique and direct filtering Fourier transform technique are explained. The error analysis of both techniques applied for different classes of interferograms is presented. The methodology of CCF interferogram analysis based on FT methods applied for micromembranes is presented and several exemplary results are given.

Integrated microinterferometric sensor for in-plane displacement measurement

We present an integrated sensor based on a grating interferometer (GI) for in-plane displacement measurement in microregions of large engineering structures. The system concept and design, based on a monolithic version of Czarneks GI, is discussed in detail. The technology chain of the GI measurement head (MH), including the master fabrication and further replication by means of hot embossing, is described. The numerical analyses of the MH by means of geometric ray tracing and scalar wave propagation are provided. They allow us to determine geometrical tolerance values as well as refractive index homogeneity and nonflatness of MH working surfaces, which provide proper beam guiding. Finally the demonstrative measurement performed with a model of the sensor is presented.

Silicon comb-drive X-Y microstage with frame-in-the-frame architecture for MOEMS applications

In this paper we present the silicon comb-drive X-Y microstage with the frame-in-the-frame architecture intended to be monolithically integrated with a glass microlens as a MOEMS 2D scanner for the Miniaturized Confocal Microscope On- Chip. The microstage is characterized by relatively large travel range (± 35 μm in X-direction and ± 28 μm in Y-direction at 100 V) for a small number of driving electrodes, without noticeable mechanical X-Y crosstalk. We describe the design, ANSYS modeling, fabrication process and static characterization of the device.