In this paper, we introduce a digital holographic camera objective based on conventional customer-oriented components for off-axis external white light illumination. The interferometric module based on a modified common-path point diffraction interferometer provides a direct view of the system and admits self-reference and self-interference operation modes. The proposed system is designed for self-emitting and reflective samples. Its modular assemblage provides easy scalability and up-grade possibilities. The operability of the suggested camera system has been proven for both coherent and low-coherent broadband sources, and reconstructed amplitude and phase information of test samples under white light illumination is presented.
Within this work we propose a new technique for diagnostics of dispersed media using the shock waves generated with continuous laser radiation of moderate power. Within this technique it is possible to determine geometrical sizes of the dispersed particles as well as the absorption coefficient of the disperse medium. Under long-term influence of the optical field of power less than 100 mW observable disperse medium is not destroyed which can be applied in the micro- and nanotechnologies and in biomedicine.
Focusing the continuous laser radiation on the water with absorbing particles results in the emergence of shock waves and medium blooming periodic in time. The illuminating beam diameter growth at the constant laser power results in the decrease of the signals’ modulation frequency, improving their stability and increasing their amplitudes. The decrease of signal’s modulation frequency is caused by the growth of time, which is needed for heating the medium to the critical temperature. Improving the stability and the increase of optical and acoustic signals’ amplitudes take place due to the growth of the number of particles participating in cavitation.
Water suspension of absorbing nano-sized particles is an example of a medium in which non-linear effects are present at moderate light intensities, which is applicable to optical treatment of biological objects. The experiment was dedicated to the phenomena emerging in a thin layer of such a medium under the action of inhomogeneous light field formed due to the Pearcey diffraction pattern near a microlens focus. In this high-gradient field, the light energy absorbed by the particles induces inhomogeneous distribution of the medium refraction index, which results in observable self-diffraction of the falling light, depending strongly on the medium position with respect to the focus.