V. P. Ryabukho

What type of coherence of the optical field is observed in the Michelson interferometer

The types and corresponding coherence functions of the optical field are considered depending on the frequency and angular spectra of the field. The main concepts of the theory of coherence effects in the interference experiment with the amplitude splitting of the initial field are discussed. It is shown that, in strict correspondence with the theory of coherence of the random wave fields, the Michelson interferometer reveals manifestations of the transverse and longitudinal spatial (rather than temporal, as it is commonly adopted) coherence of the optical field; the purely temporal coherence of the optical field is revealed only under special conditions of the interference experiment. Beyond these conditions, either spatial or spatiotemporal coherence is revealed.

Reconstruction of the hologram structure from a digitally recorded Fourier specklegram

The possibilities of reconstructing the hologram structure and image from a digitally recorded Fourier specklegram without reference beam have been considered. The mechanisms of recording in the hologram structure and reconstructing information about the amplitude and phase spatial distributions in optical fields are discussed. Schemes for recording Fourier specklegrams are considered. The results of reconstruction of the hologram structures and images of flat scattering objects of different shapes are presented.

Reconstructing Spatial Phase Distributions and Object Images from Speckle Intensity Patterns of the Diffraction Field

A method of reconstruction of the spatial phase distribution and the image of a scattering object from a recorded speckle pattern of the diffraction field has been developed and verified on test objects. The proposed method is based on an assumption that, for objects of a certain class, the phase difference between adjacent speckles in the far zone is equal to π. Digital records of Fourier speckle patterns and the corresponding digitally reconstructed images are presented.

The Influence of the Spectral Properties of Human Skin on the Resolution of a Linnik Interference Microscope

We present the results of modeling a signal in low coherent microinterferometry for different broadband sources of radiation taking into account the spectral characteristics of the optical elements, including the controlled object. We show the influence of the spectral characteristics of the object under study, human skin in particular, on the resolution of a low coherent microinterferometer. The values of interference pulse width are obtained while studying human skin using a white light emitting diode and an incandescent lamp as light sources.

Change dynamics of RBC morphology after injection glucose for diabetes by diffraction phase microscope

Experimental setup of diffraction phase microscope (DPM) with double low-coherence lighting system is presented in the paper. Algorithm of interference picture processing and optical thickness, height, volume and mean cells volume (MCV) of RBC calculating is shown. We demonstrate results of experiments with blood smears and ability of the method to calculate 3D model of the biological cells shape. Investigation change dynamics of RBC morphology after injection glucose for diabetes by DPM is shown in the paper.

Method for distant diagnostics of layered media inner structure

The method of autocorrelation low coherence interferometry is proposed for diagnostics of layered media inner structure. The possible applications of this method in technology and biomedicine are presented. In this method the low coherence optical field is reflected from the objects structure and then analyzed using the Michelson interferometer. Since the object is outside of the Michelson interferometer the axial position of the object is not important and thus the object can move during the measurements. The theoretical background of this autocorrelation method for a media with discrete and continuous optical structure modification is presented.

Full-field micro-interferometry of crystallized blood plasma

Study of a protein water solution dehydration processes gives rise to a novel diagnostics methods [1,2]. Self-assembly of a drying bioliquid depends on many physical and physicochemical parameters, the slightest changes of which induce essential changes in size, arrangement and symmetry of characteristic elements of observed patterns. Various pathological processes, being taking in human organism, cause alteration of the physicochemical state of explored bioliquid. Further investigation of this problem requires instrument making it possible to efficiently track in real time drop spatial formation that would allow study of dehydration dynamics and influence of chemical and physical parameters of the solution on it.

Autocorrelation low coherence interferometry for scattering media

Method of autocorrelation low coherence interferometry (LCI) is investigated in the work and proposed for diagnostic of layered media inner structure. The autocorrelation LCI is non reference beam method [1–3]. A sample beam directs to the interferometer where optical path difference between the waves reflected from different layers within the sample is compensated. In these methods an object is out of interferometer. So any distance to object is suitable and movements of object do not influence on interference signal. The output signal represents sample field autocorrelation function. Variable component of output signal Ĩ(2Δz<inf>M</inf>) is: given equation where Δt=2Δz<inf>M</inf>/c, Δt<inf>ij</inf>=2d<inf>ij</inf>n<inf>ij</inf>/c, d<inf>ij</inf>n<inf>ij</inf> - is the optical thickness of layer contained by i-th and j-th boundaries, λ<inf>0</inf>=2πc/ω<inf>0</inf> [4,5]. There is a central pulse which corresponds to zero path difference between two sample fields in the interferometer. The side pulses are located symmetrically about the central. Location of side pulses in interference signal shows optical thicknesses of layers and serial combinations of theirs within the sample. Total number of side pulses is N = 1/2*(m² − m), where m - is the number of reflecting boundaries. Several technical and biological objects (including skin abruption and nanorods of gold [6]) were investigated using the method. Result of scanning of skin abruption is shown on fig. 1. The scheme of the object (fig. 1a) and interference signal of it (fig. 1b) are presented.