23 research outputs found
ΠΡΠ³Π»Π΅ΡΠ΅Π²Ρ Π½Π°Π½ΠΎΡΠ°ΡΡΠΈΠ½ΠΊΠΈ. ΠΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½Π½Ρ, Π²Π»Π°ΡΡΠΈΠ²ΠΎΡΡΡ, ΠΏΠ΅ΡΡΠΏΠ΅ΠΊΡΠΈΠ²ΠΈ Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½Ρ
The paper 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 β 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.Π ΠΎΠ±ΠΎΡΠ° ΠΏΡΠΈΡΠ²ΡΡΠ΅Π½Π° Π²ΠΈΠ²ΡΠ΅Π½Π½Ρ ΠΎΠΏΡΠΈΡΠ½ΠΈΡ
Π²Π»Π°ΡΡΠΈΠ²ΠΎΡΡΠ΅ΠΉ ΠΊΠ°ΡΠ±ΠΎΠ½ΠΎΠ²ΠΈΡ
Π½Π°Π½ΠΎΡΠ°ΡΡΠΈΠ½ΠΎΠΊ, ΡΠΈΠ½ΡΠ΅Π·ΠΎΠ²Π°Π½ΠΈΡ
Π·Π° ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΎΡ, ΡΠΎΠ·Π²ΠΈΠ½ΡΡΠΎΡ Π² Ρ
ΠΎΠ΄Ρ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ
Π½Π°ΠΌΠΈ Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΈΡ
Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Ρ. ΠΠΈΠ·Π½Π°ΡΠ΅Π½ΠΎ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½Ρ ΡΠΌΠΎΠ²ΠΈ ΡΡΠ²ΠΎΡΠ΅Π½Π½Ρ Π²ΡΠ³Π»Π΅ΡΠ΅Π²ΠΈΡ
Π½Π°Π½ΠΎΡΡΡΡΠΊΡΡΡ Π· Π½Π°ΠΏΠ΅ΡΠ΅Π΄ Π²ΠΈΠ·Π½Π°ΡΠ΅Π½ΠΈΠΌΠΈ Π²Π»Π°ΡΡΠΈΠ²ΠΎΡΡΡΠΌΠΈ. ΠΡΡΠΈΠΌΠ°Π½ΠΎ Π½Π°Π½ΠΎΡΠ°ΡΡΠΈΠ½ΠΊΠΈ Π΄ΠΎ ΡΠΎΠ·ΠΌΡΡΡΠ² ΠΏΠΎΡΡΠ΄ΠΊΠ° 100 Π½ΠΌ, ΠΌΠ°ΠΊΡΠΈΠΌΡΠΌ ΠΏΠΎΠ³Π»ΠΈΠ½Π°Π½Π½Ρ ΡΠΊΠΈΡ
Π»ΠΎΠΊΠ°Π»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠΉ Π½Π° Π΄ΠΎΠ²ΠΆΠΈΠ½Π°Ρ
Ρ
Π²ΠΈΠ»Ρ Ρ ΡΡΠΎΠ»Π΅ΡΠΎΠ²ΠΎ-ΡΠΈΠ½ΡΠΉ ΠΎΠ±Π»Π°ΡΡΡ ΡΠΏΠ΅ΠΊΡΡΠ°, Π° ΠΌΠ°ΠΊΡΠΈΠΌΡΠΌ Π»ΡΠΌΡΠ½ΡΡΡΠ΅Π½ΡΡΡ Ρ Π·Π΅Π»Π΅Π½ΡΠΉ ΠΎΠ±Π»Π°ΡΡΡ ΡΠΏΠ΅ΠΊΡΡΠ°. ΠΡΠΎΠ±Π»Π΅Π½ΠΎ ΠΏΡΠΈΠΏΡΡΠ΅Π½Π½Ρ ΠΏΡΠΎ ΠΌΠΎΠΆΠ»ΠΈΠ²ΡΡΡΡ Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½Ρ ΠΎΡΡΠΈΠΌΠ°Π½ΠΈΡ
ΡΠ°ΡΡΠΈΠ½ΠΎΠΊ Π΄Π»Ρ ΠΊΠΎΡΠ΅Π»ΡΡΡΠΉΠ½ΠΎΡ Π΄ΡΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ ΠΎΠΏΡΠΈΡΠ½ΠΈΡ
ΡΠΏΠ΅ΠΊΠ»-ΠΏΠΎΠ»ΡΠ²
Modeling of the high-resolution optical-coherence diagnostics of bi-refringent biological tissues
We present a computer model of the polarization-sensitive interference diagnostics of the bi-refringent biological media, with a particular example of the lamella of eye cornea. The diagnostic procedure employs the modified MachβZehnder interferometer with controllable phase retardation of the reference wave, separate observation of the orthogonal linearly-polarized interference signals, and evaluation of the phases and amplitudes of their variable (AC) components. The data obtained permit to determine the mean refractive index as well as the difference between the extraordinary and ordinary refractive indices, which, in turn, indicates the optical axis and the collagen fibersβ orientation in the lamella. The modelled procedure enables the sample structure diagnostics with the longitudinal and lateral resolution βΌ100Β nm and βΌ1.8Β ΞΌm, correspondingly. In particular, it permits a reliable detection and quantitative characterization of a thin (<100Β nm) near-surface layer where the mean refractive index differs by less than 1% from that in the main volume (due to the different orientation of the collagen fibers). The diagnostic approach, developed in the paper, can be useful in various problems of structure characterization of optically-anisotropic biological tissues
Orbital rotation without orbital angular momentum: mechanical action of the spin part of the internal energy flow in light beams
It is known that internal energy flow in a light beam can be divided into the
orbital flow, associated with the macroscopic energy redistribution within the
beam, and the spin flow originating from instantaneous rotation of the field
vectors inherent in circular or elliptic polarization. In contrast to the
orbital one, experimental observation of the spin flow constituent seemed
problematic because (i) it does not manifest itself in the visible
transformation of the beam profile and (ii) it converts into the orbital flow
upon tight focusing of the beam, usually employed for the energy flow detection
by the mechanical action on probe particles. We propose a two-beam interference
technique that permits to obtain appreciable level of the spin flow in
moderately focused beams and to detect the orbital motion of probe particles
within a field where the transverse energy circulation is associated
exclusively with the spin flow. This result can be treated as the first
demonstration of mechanical action of the spin flow of a light field.Comment: 9 pages, 3 figures and 1 video cli
Scattering of inhomogeneous circularly polarized optical field and mechanical manifestation of the internal energy flows
Based on the Mie theory and on the incident beam model via superposition of
two plane waves, we analyze numerically the momentum flux of the field
scattered by a spherical microparticle placed within the spatially
inhomogeneous circularly polarized paraxial light beam. The asymmetry between
the forward- and backward-scattered momentum fluxes in the Rayleigh scattering
regime appears due to the spin part of the internal energy flow in the incident
beam. The transverse ponderomotive forces exerted on dielectric and conducting
particles of different sizes are calculated and special features of the
mechanical actions produced by the spin and orbital parts of the internal
energy flow are recognized. In particular, the transverse orbital flow exerts
the transverse force that grows as a^3 for conducting and as a^6 for dielectric
subwavelength particle with radius a, in compliance with the dipole mechanism
of the field-particle interaction; the force associated with the spin flow
behaves as a^8 in both cases, which testifies for the non-dipole mechanism. The
results can be used for experimental identification and separate investigation
of the spin and orbital parts of the internal energy flow in light fields.Comment: 17 pages, 5 figures. For resubmission, the language is improved,
numerical mistakes in Fig. 4 are corrected and discussion is modified
accordingl