Novel glasses based on TeO2-P2O5-ZnO-MxOy-PbF2 doped by rare earths for laser operated optical anisotropy are proposed. We have discovered an increase of birefringence within coherent laser densities within the 200...500 MW/cm2 power densities up to 5×10-5. After it is enhanced more slowly and is saturated after 800 MW/cm2. The glasses have been treated by two bicolour laser beams which propagated under the incident angles varying within the 22…25 degree for 45 degree light polarization. The photoinducing beam have been formed by the 10 ns Nd:YAG laser with 10 Hz frequency repetition. The set of polarizers, lenses and mirrors have been used for formation of the photo inducing laser beams with the desired parameters. The all investigated glasses in temperature interval within the 20°C up to 300°C show the same mechanism of electric charge transport. We have discovered that the glasses possess a high thermostability with the small exception for the first two cycles of heating-cooling and for all the glasses for the third and higher cycling. Addition of rare earth elements has not a huge influence on their stability. The maximal changes are observed for TiO2 containing compounds, the middle one – for ZnO and the lowest for WO3. The laser operation has been performed by simultaneous treatment by two bicolor coherent beams. The relaxation processes are equal to about several minutes. Here principal role play polarizabilities of the Ti ions which are maximal and the relatively higher atomic radiuses for Zn and W. The obtained glasses may be promising for laser stimulated fibers during transmission of optical information.
A laser operated nanocomposites for linear electrooptics modulators based on cadmium sulfide (CdS) nanoparticles synthesized by electrochemical anodizing method in the polyvinyl alcohol (PVA) solvent are realized. The basic components are CdS nanoparticles. The XRD data confirm that the wurtzite component content was varied within the 10 % to 27%. Varying PVA solvent the average sizes have been changed. The synthesized powders consist of nano-sized particles with sizes varying within 11 nm…14.5 nm. It is demonstrated an influence of PVA content on the grain sizes. The diameter of particles of CdS is enhanced with an increasing PVA content. The PVA causes a significant increase in the size of the particles. The photoinduced electrooptics has been performed using as a photoinducing 120 fs femtosecond laser at 1045 nm. The linear electrooptics was probed by He-Ne cw laser at 1150 nm. A correlation between the content of wurtzite CdS component and the output electrooptics is found. The maximal values are achieved for the 83.8 % of wurtzite CdS component. For other content of wurtzite CdS these values are less. This one reflect a fact of significant role of acentric crystallites in the observed dependences that may be used for the further search and design of the laser operated electrooptical materials in a future development of laser modulators and laser triggers. Additional important role is played by interfaces. The principal physical origin of the effect is caused by interfaces between the nanoparticles and structurally disordered background. The effect is completely irreversible and disappears after several seconds.
We report the energetic 8 MeV electron beam induced modification on linear and nonlinear optical process in Mn doped ZnO (MZO) thin films at different irradiation dosage. The modifications incorporated on third order nonlinear optical absorption were studied using Z-Scan technique in both continuous and pulsed laser regime. Open aperture Z-scan measurement indicates that pristine and film treated at 15 kGy electron beam dosages reveals reverse saturable absorption (RSA) mechanism and films treated at 5 kGy, 10 kGy and 20 kGy exhibits saturable absorption (SA) phenomena. The irradiation resulted in a high βeff value of 12.1 ×10-2 cm/W in continuous wave excitation and 5.6×10-4 cm/W for pulsed excitation as compared pristine films. Gaussian deconvolution fitting on room temperature PL spectra shows a quenching of defect centers upon electron beam irradiation. The observed decrement in PL emission intensity for the films treated with energetic electron beam can be probably due to recombination of defect centers and enhanced non radiative defects. The decrease in the energy band gap and increase in the urbach energy of the MZO thin films was observed due to creation of deep energy levels into the band gap. The irradiation treatment resulted in significant changes on the crucial parameters of optical sensing such as limiting threshold and optical clamping. The present study indicates that nonlinear parameters of MZO thin films can be tuned by choosing appropriate electron beam dosage for photonics applications.
For the first time we have shown that increasing uniaxial pressure on the triglycine selenium single crystals leads to the
occurrence of several spectral maxima below the energy gap. It is principal that after interruption of the applied uniaxial
pressure one observes remarkable spectral shifts up to 20 nm of the principal spectral maxima at 280 nm and 340 nm.
The effect is caused by the changes of inter-molecular interactions of the van der Waals type in such kinds of crystals
and occurrence of in elastic interactions. The effect has irreversible character and after applying of uniaxial pressure
several times we see that there occur several strains which may be considered as the remaining infer-molecular stresses.
The observed phenomenon may be used for creation of the optoelectronic tensors of the pressure with the forces up to 4
kG. The performed investigations have shown that the spectral broadening is not sensitive to the pressure, however their
spectral shifts are substantially sensitive to the applied pressure. The observed effect possess a long time reversibility (up
to one month). Additional studies of piezooptical effects have shown its sensitivity to the external cw green laser light at
power 300 mW. Using the thermoluminescence we have established that the crystals are very sensitive to the number of
trapping levels within the energy gap. Additionally there were performed studies of electrooptical effects for the pulsed
10 ns Nd:YAG laser.
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