This paper addresses the problem of image fusion of optical (visible and thermal domain) data and radar data for the purpose of visualization. These types of images typically contain a lot of complimentary information, and their joint visualization can be useful and more convenient for human user than a set of individual images. To solve the image fusion problem we propose a novel algorithm that utilizes some peculiarities of human color perception and based on the grey-scale structural visualization. Benefits of presented algorithm are exemplified by satellite imagery.
Nonlinear refraction has been for the first time studied in silicon carbide nanocrystal films synthesized by new technique
of direct carbide and silicon ion deposition with ion energy of 100eV and low substrate temperature from 900°C to
1150°C. The films were shown to exhibit large optical nonlinear cubic susceptibility χ(3) ≅ 10-6 esu (λ=1064nm and λ=532nm, τи = 10ns).
Giant nonlinear refraction has been experimentally observed in gold island films. The complex third-order nonlinear
susceptibility χ(3)(ω;ω,-ω,ω) reaches a value of -8×10-5 esu (λ = 532 nm, ι = 10 ns) and (+5×10-7 + i0.3×10-7) esu (λ = 800 nm, ι = 85 fs). The mechanism of nonlinearity of the refractive index can be associated with the resonance enhancement of the factor of the local optical field at the pump wavelength due to the excitation of surface plasmons, as
well as with the contribution of the heating of conduction electrons in an ensemble of metal particles.
Giant nonlinear refraction has been experimentally observed in gold island films. The real part of the third-order
nonlinear susceptibility χ(3)(ω;ω,-ω,ω) reaches a value of -8×10-5 esu (λ = 532 nm, τ = 10 ns) and +5×10-7 esu (λ = 800
nm, τ = 85 fs). The mechanism of nonlinearity of the refractive index can be associated with the resonance enhancement
of the factor of the local optical field at the pump wavelength due to the excitation of surface plasmons, as well as with
the contribution of the heating of conduction electrons in an ensemble of metal particles.
The Ti-doped CdTe semiinsulating crystals of high optical quality were grown by the vertical Bridgman technique. The complex optical, photoelectric and photorefractive measurements of CdTe doped with Ti atoms were carried out. It allowed to our knowledge for the first time to determine the photorefractive characteristics of these crystals. Studies of the optical absorption and photodiffusion current made it possible to determine the nature and energy structure of impurity and intrinsic defects as well as to establish their role in the photorefractive effect. It was shown that the excited 3T1(P) state is in resonance with the conduction band. As a result of it the auto-ionization of electrons to the conduction band under the laser excitation take place. The energy-level diagram both of impurity and intrinsic defects in the CdTe:Ti crystals was constructed. It was shown that titanium dopant have advantage over other dopants and that CdTe:Ti has better characteristics for a potential applications. Obtained parameters: high optical holographic gain coefficient (up to 0.60 cm-1), low background absorption (about 0.1 - 0.2 cm-1), high optical quality and homogeneity, almost electronic type photoconductivity (electron-hole competition factor equals 0.94) show that this material can be effectively used as sensor components for both optical and photoelectric applications in the near infrared region.
Tin is shown to be a suitable dopant that makes it possible to grow cadmium telluride crystals with considerably reduced conductivity (semi-insulating material) and ensures a well pronounced photorefractive response both for cw and Q- switched Nd3+:YAG laser radiation.
Measurements are presented for the photorefractive grating recording under pulsed excitation in the crystal of CdTe doped by Fe. The crystal under study is characterized by high electron mobility in comparison with typcial value. The photorefractive parameters of the crystal such as gain factor, Debye screening length, effective density of charge traps as well effective electro-optic constant have been measured on the basis of gain/grating spacing, gain/crystal rotation angle at different recording beam polarizations, and gain/intensity at different crystal orientations dependencies. The electron-hole competition influence on the crystal photorefractive performance is discussed. The fast photorefractive effect was shown to occur under pulsed excitation maximum gain factor, (Gamma) , being equal to approximately 0.3cm-1 without any externa electric field. Different self-action effects accompany two-beam coupling are discussed. These are two photon absorption, free carrier generation, self-action of laser beams. The photorefractive effect was separated in its pure form from the various nonlinear optical phenomena.
The performance of a recently developed nonlinear optics epoxy-based polymer with covalently attached dye molecules is investigated. Large refractive nonlinearity is observed. The refractive index nonlinear coefficient and relaxation time were measured using a degenerate two beam coupling scheme with a frequency doubled Nd3+:YAG laser. We have used a thin polymer film for dynamic holography recording. Peculiarities of self- diffraction at the holograms are discussed for both dynamic and stationary hologram recording. The possibilities to write and erase phase gratings reversibly by ns-pulses and store information for hours are demonstrated. An analysis of possible mechanisms for the refractive index nonlinear behavior is presented. The results vividly manifest the possibility of the polymer to be used as reversible medium for information storage. Besides, the polymer structure in question exhibits both ns and quasi-stationary response together with simplicity of fabrication and low prises which have wide prospects for different applications in the field of optical data processing.
Measurements are presented for the photorefractive grating recording under pulsed excitation in the crystal of CdTe doped by Fe. The crystal under study is characterized by high electron mobility in comparison with typical value.THe photorefractive parameters of the crystal such as gain factor, Debye screening length, effective density of charge traps as well as effective electro-optic constant have been measured on the basis of gain/grating spacing, gain/crystal rotation angle at different recording beam polarizations, and gain/intensity at different crystal orientations dependencies. The electron-hole competition influence on the crystal photorefractive performance is discussed. The fast photorefractive effect was shown to occur under pulsed excitation maximum gain factor, (Gamma) , being equal to approximately 0.3 cm-1 without any external electric field. Different self-action effects accompany two-beam coupling are discussed. These are two photon absorption, free carrier generation, self-action of laser beams. The photorefractive effect was separated in its pure form from the various nonlinear optical phenomena.
The performance of a recently developed nonlinear optics epoxy-based polymer with covalently attached dye molecules is investigated. Large refractive nonlinearity is observed. The refractive index nonlinear coefficient and relaxation time were measured using a degenerate two beam coupling scheme with a frequency doubled Nd3+:YAG laser. We have used a thin polymer film for dynamic holography recording. Peculiarities of self diffraction at the holograms are discussed for both dynamic and stationary hologram recording. The possibility to write and erase phase gratings reversibly by ns-pulses and store information for hours are demonstrated. An analysis of possible mechanisms for the refractive index nonlinear behavior is presented. The results vividly manifest the possibility of the polymer to be used as reversible medium for information storage. Besides, the polymer structure in question exhibits both ns and quasi-stationary response together with simplicity of fabrication and low prices which have wide prospects for different applications in the field of optical data processing.
Nonlinear refraction of a new polymer structure based upon diglycidylether of bisphenol-A has been studied. The polymer contains 4-aminoazobensen as nonlinear optically active side groups covalently attached to each monomer unit. Thin dynamic grating writing and relaxation processes have been studied using frequency doubled YAG:Nd+3 laser ((lambda) equals 0.53 micrometers ). The dynamics of transient gratings was shown to have two different erasure times corresponding two different nonlinearity mechanisms fast one (relaxation time (3) equals 5 (DOT) 10-8 esu) and slow one (quasi-stationary). The later makes it possible to write and erase phase gratings reversibly by ns pulses. An analysis of possible mechanisms for refractive index nonlinear behavior in new structures is presented. In particular, a role of TRANS-CIS photoisomerization of the azo-compound in nonlinear optical properties of the structure are discussed.
Nonlinear refraction of a new polymer structure based upon diglycidylether of bisphenol-A has been studied in connection with transient holographic grating recording. The polymer contains 4 aminoazobensen as nonlinear optically active side groups covalently attached at each monomer unit. Dynamic grating writing and relaxation processes have been studied using frequency doubled YAG:Nd+3 laser ((tau) p equals 20 ns, (lambda) equals 0.53 micrometers ). The dynamics of transient gratings was shown to have two different erasure times corresponding to different nonlinearity mechanisms fast one (relaxation time 20 ns and (chi) (3) equals 5 (DOT) 10-8 esu) and slow one (quasi-stationary). The later makes it possible to write and erase phase gratings reversibly by ns pulses and store information for hours. An analysis of possible mechanisms for refractive index nonlinear behavior in new structure is presented. In particular, a role of TRANS-CIS photoisomerization of the azo-compound in nonlinear optical properties of the structure is discussed. The results vividly manifest the possibility of the polymer to be used as reversible medium for information storage. Besides, the polymer structure in question exhibits both ns and quasistationary response together with simplicity of fabrication and low prises which have wide prospects for different applications in the field of optical data processing.
Transverse optical bistability investigation review is presented. Aberration theory of the transverse optical bistability with counter-propagating light beam interaction is developed. The effect of aberration phenomena on switching thresholds is described and theoretical results are compared with experimental observations in α-SiC(6H) crystal.
Measurements are presented for the photorefractive effect in CdTe using 10-ns pulses at a wavelength of 1.06 μm. Different self-action effects that accompany two-beam coupling are discussed.
Transverse optical bistability switching dynamics of self-focusing counter-propagating laser beams in a nonlinear medium are investigated by analytical and numerical methods. Cavityless transverse optical bistability in a thin silicon carbide crystal has been implemented experimentally with a characteristic switching time of about 10-10 s.
Methods for the nonlinear refractive index measuring in a dissipative medium are elaborated. The fast nonlinearity dispersion is measured in (alpha) -SiC(6H) crystals in the intersubband absorption range (hw approximately 2 eV). The conclusion is made regarding silicon carbide nonlinearity mechanism.
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