The paper offers a new approach associated with the use of luminescent carbon nanoparticles for the studies of super-smooth surfaces (Rq~4–5 nm). Fluorescent nanoparticles can serve as highly-sensitive probes of the object surface inhomogeneities, realizing a contactless version of the atomic-force profilometry. Using structured light for particles’ fluorescence excitation enables to resolve the fine structural units of the surface relief in the nanometer range. The use of nanoparticles as a probe makes it possible to circumvent the spatial-resolution limitations of optical systems dictated by the classical wave-optics concepts (Rayleigh limit).
Possibilities of geometric phase using in low-coherence polarization-sensitive tomography tasks for noninvasive diagnostics of surface (subsurface) layers of transparent biological media (samples and tissues) are considered. Determination of the object fields’ geometric phase in the modified Mach-Zehnder interferometer allows one to reproduce the geometric structure (optical axis/collagen orientation) of birefringent biological medium. Polarization-interference noninvasive approach of diagnostics the collagen orientation structure of thin nanosized surface tissue layers is proposed at the first time. It is shown, that taking into account the information about top (surface) layer structure can significantly improve the accuracy of deeper (subsurface) layers parameters estimation. The proposed solution is a unique feature that is not accessible in classical polarization-sensitive techniques of information recovery on tissue structure.
We introduce a computer model for polarization-sensitive interference-based diagnostics of birefringent biological samples, focusing on a specific example, the lamella of the cornea in the eye. This diagnostic technique utilizes a modified Mach-Zehnder interferometer with adjustable phase retardation for the linearly polarized reference wave, allowing separate observation of the orthogonal linearly polarized interference signals. By analyzing the mean (dynamic) and Pancharatnam-Berry phase of object field and its amplitude components, we can derive the information about medium properties, such as birefringence and optical axis orientation. The methodology outlined in the paper has the potential to be valuable in addressing a variety of structural characterization challenges in optically anisotropic biological tissues.
Method based on polarization-interference for determination the geometric and dynamic phase in a case of linearly birefringent, internally reflective media is proposed. The object is probed by horizontally polarized incident beam, and the resulting interference distribution consist of two components depending on medium orientation. The interference of horizontal components of object and reference field allows one to estimate the sum of dynamic and geometric phases, while the vertical components interference produce the dynamic phase. The proposed method allows one to estimate the geometric phase value in a case of only one input polarization state.
Model of polarized light interaction with anisotropic biological medium, on the example of eye cornea, is given. The polarization of the object field, which occurs during propagation through a birefringent medium, in the case of a linearly polarized incident wave, is analyzed. A polarization-interference approach for determining the polarization characteristics of the medium is proposed, which consists in analyzing the change in polarization of the field that occurs during interference of the object and reference beams. The condition of compensation of the dynamic phase allows to obtain a polarization state, determined exclusively by the geometric phase of the object field, which contains information about the polarization properties of the medium. The geometric phase value was evaluated by the geodesic triangle on the Poincaré sphere, which made it possible to restore the orientation of the optical axis (collagen fibers) of the biological medium.
A new polarization-interference approach based on geometric phase for estimation of optically anisotropic media properties, is proposed. Linearly birefringent object is probed by linearly horizontally polarized incident beam, and the resulting polarization depends on the medium properties such as birefringence (phase retardation) and optical axis orientation. The modified Mach-Zehnder interferometer is used to obtain the polarization-interference pattern in two channels for determination the dynamic and geometric phase. The dynamic phase depends on the mean refractive index and allows to estimate the medium thickness, while the geometric phase is the function of medium polarization properties (birefringence and optical axis orientation). Thus, the dynamic and geometric phase values allow to estimate the medium optical properties, such as optical thickness, phase retardation and/or optical axis rotation.
This study proposes a new approach for correlation-optical diagnostics of a complex optical field created by light scattering on a rough surface. The possibility of using fluorescent nanoparticles of a size of about 30-120 nm for diagnosing the distribution of optical flows in the speckle field has been analyzed. A model experiment for investigation motion of carbon nanoparticles in a speckle field is demonstrated. Under the influence of gradient optical forces, carbon nanoparticles move in an optical field and are captured by the singularities of the field. The change of particle position in time in a three-dimensional field due to the action of longitudinal and transverse component of optical force is demonstrated.
In this paper a new approach that enables to analyze the structure and reconstruct a rough surface with inhomogeneities is suggested, for which the heights distribution from the trough to the upper point is about 20 nm. For such diagnostics, carbon nanoparticles are used, which are characterized by luminescence in the yellow-green region of the spectrum and such a value of the dipole moment, which makes it possible to control the distribution of nanoparticles over the surface even in the presence of an external electric field. As a probe for diagnosing nanoparticles, it is suggested to use structured light with a significant longitudinal field component, which largely removes the limitations imposed by the transverse resolution of the optical system. The recorded luminescence of carbon nanoparticles with dipole moment oriented parallel to the longitudinal component of the field, enabled not only to reproduce the location of maxima and minima of the surface with an accuracy of 12.9%, but also to reconstruct the landscape of the studied surface itself at a level of 6.76% error.
This study examines a model for analyzing the behavior of carbon nanoparticles in speckle field under the influence of optical forces. As a result of computer modeling, optical parameters of carbon nanoparticles were calculated, which made it possible to assess the optical forces (gradient, absorbing and scattering components) acting from internal energy flows in the optical field on carbon nanoparticles. The influence of size of carbon nanoparticles on the ratio of components of optical force is analyzed. Conditions are defined when the amount of gradient force will be significant, which will set the spatial movement of carbon nanoparticles in the area of the minimum, in particular in singular points.
A new approach of carbon nanoparticle using for the optical diagnostics of а complex scalar optical field obtained by scattering and diffraction of radiation on a surface with roughness is suggested in this paper. Luminescence of carbon nanoparticles made it possible to register their coordinate position in time. The algorithm for the reconstruction of scalar optical field intensity distribution through the analysis of nanoparticle position was proposed in the paper. The phase map of the optical speckle field was analyzed by a Hilbert transform filter to restore the phase of the entire object. A special attention was paid to the restoration of the phase singularities of the speckle field of the scattering studied object.
The idea of the proposed paper is to demonstrate the influence of the evanescent wave on nano-objects of inorganic and organic origin localized in a biological medium, in the direction perpendicular to the direction of the Pointing vector action. Experimental condition of evanescent wave exitation is considered in the given paper. A total internal reflection was realized at the interface between the prism and a biological medium when a linearly polarized wave with the azimuth of polarization of ±45° acts on the surface. The result of this action is a complex distribution of the optical flow density both in the longitudinal direction coinciding with the direction of the wave vector and in the transverse direction perpendicular to the wave vector. The paper presents some of the latest theoretically and experimentally obtained results illustrating the rectilinear and rotational motion of investigated objects in a biological environment.
A new approach of carbon nanoparticle using for the optical diagnostics of а complex scalar optical field obtained by scattering and diffraction of radiation on a surface with roughness is suggested in this paper. Luminescence of carbon nanoparticles made it possible to register their coordinate position in time. The algorithm for the reconstruction of scalar optical field intensity distribution through the analysis of nanoparticle position was proposed in the paper.
The work is devoted to the study of the optical properties of carbon nanoparticles synthesized by the method developed during our experimental studies. The optimal conditions for the creation of carbon nanostructures with predetermined properties are defined. Nanoparticles of the size of about 100 nm were obtained, the maximum of absorption of which is localized at wavelengths in the violet-blue region of the spectrum, while the maximum of luminescence – in the green region of the spectrum. The assumption is made about the possibility of using the obtained particles for correlation diagnostics of optical speckle fields.
The use of carbon particles for the correlation and optical diagnostics of speckle fields obtained by diffraction on a surface with a roughness is suggested in this research. The optical properties of carbon nanoparticles, such as luminescence and absorption in the visible spectrum, as well as particle sizes of about hundreds nanometers, are the determining criteria for using these particles as an optical field probe. The obtained optical speckle field was analyzed by a 2D Hilbert transform to restore the phase of the entire object with high accuracy.
Theoretical approach for the red blood cell (erythrocyte) motion, controlled by the action of evanescent wave, generated by the total internal reflection at the inner cell surface, is proposed. Model situation describing the conditions for transverse motion of erythrocyte caused by the transverse spin momentum is presented. Motion peculiarities of a red blood cell in an isotonic solution depending on illumination conditions are estimated. Considered approach enables to expand the possibilities for the microobjects motion control in biomedical applications.
Theoretical approach of the mechanical action modelling, based on the interaction of the evanescent wave, arising due to the total internal reflection (TIR) at the birefringent microplate-air interface, with the surface roughness, is proposed. The value of optical forces, caused by spin and orbital momentum of evanescent wave, generated by linearly polarized incident wave with the azimuth of polarization of ±45° is estimated. Conditions for which the action of transverse component of optical force is significant are determined. The proposed approach spread the possibilities of optical manipulation of microand nanoobjects in near field.
The paper presents main theoretical approaches allowing for calculation of optical force and torque in a birefringent medium under the condition of total internal reflection realization. Evanescent wave realized under the plate is elliptically polarized, possesses spin angular momentum and is a cause of object motion. In this case linearly polarized incident wave with the azimuth of polarization of ±45° forms vertical spin, which determines the transversal motion of the object and it is demonstrated in the given paper. The obtained results will be of vital importance in numerous areas where one operates with minute quantities of matter such as nanophysics, nanophotonics, precise chemistry and pharmacology etc.
Additional approaches of gold nanoparticles manipulation in evanescent wave were proposed in the given paper. Vertical spin excited under the birefrigent biotissue section is transmitted to particles causing their complex motion in a surrounding fluid of tissue near the surface layer. The theoretical and experimental confirmation of the existence of the extraordinary spin momentum of the evanescent wave is proposed.
New approaches of red blood cell (erythrocyte) controlling by the action of evanescent wave is proposed in the given research work. Theoretical and experimental models for describing the conditions of the erythrocyte transverse motion and the vertical spin realization have been analyzed in the special selected schemes. The use of a linearly polarized plane wave with azimuth of ±45° in a model experiment, specially suggested in this work, allows visualizing the transverse controlled motion of the erythrocyte, which enables to claim about new possibilities for controlling microobjects in biology and medicine.
The theoretical and experimental confirmation of the existence of a transverse spin momentum in an evanescent wave excited above the surface of a birefringent biological section is suggested in this research work. The possibility of controlling gold nanoparticles by the vertical spin of an evanescent wave in a surrounding fluid of tissue near the surface layer of the section is demonstrated.
New approaches of red blood cell (erythrocyte) controlling by the action of evanescent wave is proposed in the given research work. Theoretical and experimental models for describing the conditions of the erythrocyte transverse motion and the vertical spin realization have been analyzed in the special selected schemes. The use of a linearly polarized plane wave with azimuth of ±450 in a model experiment, specially suggested in this work, allows visualizing the transverse controlled motion of the erythrocyte, which enables to claim about new possibilities for controlling microobjects in biology and medicine.
The paper presents main theoretical approaches allowing for calculation a set of optical forces and momentum in a birefringent plate. Total internal reflection at the “plate-air” interface implemented by the birefringent plate spattered with nanoparticles of gold creates the conditions for the allocation of the predominant action of the vertical spin of the evanescent wave, which has recently been predicted. The obtained results will be of vital importance in numerous areas where one operates with minute quantities of matter such as nanophysics, nanophotonics, precise chemistry and pharmacology etc.
The theoretical and experimental confirmation of the existence of a transverse spin momentum in an evanescent wave excited above the surface of a birefringent biological section is suggested in this research work. The possibility of controlling gold nanoparticles by the vertical spin of an evanescent wave in a surrounding fluid of tissue near the surface layer of the section is demonstrated.
The paper deals with the influence of an evanescent wave on the dynamics of motion of erythrocytes into blood plasma. Computer simulation of erythrocytes moving into evanescent field and experimental demonstration of the forecasted motion argue the feasibilities for control of position of cells into blood plasma. The range of velocities of transversal motion of erythrocytes due to action of the optical force of generated evanescent field is determined in a function of the angle of illumination of a cell by the linearly polarized wave with the azimuth of polarization 45°.
The influence of an evanescent field formed by two evanescent waves under the total internal reflection on the dynamics of motion of separate erythrocyte into blood plasma is demonstrated. Computer simulation of red blood cell motion into evanescent field and experimental demonstration of rotational and rectilinear motion expand the possibilities of using optical evanescent waves in applied tasks of nanophysics and biomedicine. The vertical spin produced by the illumination of a cell by the linearly polarized wave with the azimuth of polarization 45º demonstrates unique ability to control transverse motion of the nanoobject that is not characterized to the action of spin momentum inherent to the classical circular polarized optical beam.
Physical existence of the recently discovered vertical spin arising in an evanescent light wave due to the total internal reflection of a linearly polarized probing beam with azimuthal angle 45° is experimentally verified. Mechanical action, caused by optical force, associated with the extraordinary transverse component of the spin in evanescent wave is demonstrated. The motion of a birefringent plate in a direction controlled by simultaneous action of the canonical momentum and the transversal spin momentum is observed. The contribution of the canonical and spin momenta in determination of the trajectory of the resulting motion occur commensurable under exceptionally delicately determined experimental conditions.
The theoretical model for calculating the optical forces caused by the density of spin and orbital momentum and optical torque, caused by the angular momentum typical for a circularly polarized beam or a circular component of an elliptically polarized beam, is presented. The total internal reflection at the “plate-air” interface implemented by the birefringent plate spattered with nanoparticles of gold creates the conditions for the allocation of the predominant action of the vertical spin of the evanescent wave, which has recently been predicted theoretically.
The paper presents principal approaches to diagnosing the structure forming skeleton of the complex optical field. An
analysis of optical field singularity algorithms depending on intensity discretization and image resolution has been
carried out. An optimal approach is chosen, which allows to bring much closer the solution of the phase problem of
localization speckle-field special points. The use of a “window” 2D Hilbert transform for reconstruction of the phase
distribution of the intensity of a speckle field is proposed. It is shown that the advantage of this approach consists in the
invariance of a phase map to a change of the position of the kernel of transformation and in a possibility to reconstruct
the structure-forming elements of the skeleton of an optical field, including singular points and saddle points. We
demonstrate the possibility to reconstruct the equi-phase lines within a narrow confidence interval, and introduce an
additional algorithm for solving the phase problem for random 2D intensity distributions.
We propose an optical correlation algorithm for reconstructing the phase skeleton of complex optical fields from the measured two-dimensional intensity distribution. The essence of the algorithm consists in location of the saddle points of the intensity distribution and connecting such points into nets by the lines of intensity gradient that are closely associated with the equi-phase lines of the field. This algorithm provides a new partial solution to the inverse problem in optics commonly referred to as the phase problem.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.