الفهرس 
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Abstract
At the present time Lasers and laser systems extensively
used in a plethora of scientific and technological applications.
Laser can cause potentially damage in optical sensors, including
the human eye. Protection of optical sensors from fixed
wavelength exposure can be performed either using Static
protection. Such as Conventionally static spectral filters that
block radiation that alleviated this threat in chosen wavelength
ranges. Static protection main drawbacks are constant
attenuation ratio also regardless blocking radiation of it being
useful or damaging, causing information lost for wavelengths at
which the filter is active. Protecting the entire wavelength range
of a sensor would block or strongly attenuate the radiation
needed for the operation of the sensor. Alternatively, using another method such as Active protection devices that required an external triggering signal to activate the protection. The time response of active devices is slow Compared with Static protection. The active methods require more electronics compared to Static protection due to the external
trigger Moreover, external power may also be required for some
active protection methods. A major drawback with active
protection is the slow time response, which makes protection against short pulses difficult. Therefore, an effective protection method against lasers is increasing demand for new or improved OPL materials.
Nonlinear optical materials (NLO) can regulate, limit or switch laser beams. Optical limiting (OL) materials, which exhibit high transmittance and high transparency in normal light and low laser intensities and it, exhibit low transmittance at high input laser intensity through reverse saturable absorption (RSA). We presented different forms of carbon nanomaterials such single walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) using chemical vapor deposition (CVD) method. Graphene oxide (GO) using Hummer’s method. Immobilization of the prepared carbon nanomaterials in practical, flexible, and environmentally stable nanocomposites films. In addition, high-pressure catalytic Carbon mono oxide singlewalled carbon nanotubes (HiPCO-SWCNTs) immobilized inside cross-linked poly vinyl alcohol (PVA), with narrow diameters distribution using dodecyl benzenes sulfonate (SDBS) as surfactant and plasticizer. The content of HiPCO-SWCNTs was changed to be 0.05, 0.1, 0.2 and 0.3 wt٪. We studied the structural and morphological properties of the prepared Nano graphite samples and the nanocomposites films using several techniques such as highresolution scanning electron microscope (HRSEM), high resolution transmitted electron microscope (HRTEM), ultra violet visible spectroscopy (UV-Vis), Raman spectroscopy, and thermal properties using deferential scanning calorimetry (DSC). The NLO and OL properties were investigated using open aperture Z-scan
method with nanosecond Nd:YAG pulsed laser at 532 nm and
1064 nm in Q-switched mode. The nonlinear absorption coefficient (β) and third order nonlinear susceptibility ( χ3) erecalculated. The results showed that HiPCO-SWCNTs@PVA films exhibit the best visibility and optical limiting performance among other carbon nanomaterials tested in the current work. The UV–Vis, Raman spectroscopy, and Raman mapping showed that the HiPCO-SWCNTs homogenously distributed inside the PVA matrix. The (DSC) Differential Scanning Calorimetry scan curves showed that the SDBS and the HIPCO enhanced the thermal stability of the HiPCO-SWCNTs @PVA films. the Glass transition temperature (Tg) was shifted from 56 to 97◦C. and the( Tm) latent heat
melting was increased from 190 to 219◦C.The HiPCOSWCNTs@PVA film exhibit reverse saturable absorption (RSA) at both 532 and 1064 nm laser excitations, except the 0.05 wt٪ HiPCO-SWCNTs@PVA at 1064 nm showed saturable absorption (SA) behavior. The 0.3 wt٪ HiPCO-SWCNTs@PVA film showed lower OL threshold than other films at both 532 nm and 1064 nm and increased the critical value of laser fluence damage for a commercial CCD camera ≈10 times. The remarkable OL enhancement was attributed the enhanced thermal conductivity and thermal stability of the 0.3 wt٪ HiPCO-SWCNTs@PVA film. The main results of the thesis showed that the 0.3 wt٪ SWCNTs@PVA filter can be considered as superior candidates for laser protection applications.