Rajasree, K; Ravi Kumar, A V; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(Springer, April , 1992)
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Abstract:
Photothermal deflection technique was used for determining the laser damage threshold of polymer samples of teflon (PTFE) and nylon. The experiment was conducted using a Q-switched Nd-YAG laser operating at its fundamental wavelength (1-06μm, pulse width 10 nS FWHM) as irradiation source and a He-Ne laser as the probe beam, along with a position sensitive detector. The damage threshold values determined by photothermal deflection method were in good agreement with those determined by other methods.
Nampoori, V P N; Radhakrishnan, P; Kailasnath, M; Nishant, Kumar; Bikas, Ranjan(PHOTONICS-2008: International Conference on Fiber Optics and Photonics, December , 2008)
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Abstract:
The direction dependant wavelength selective transmission mechanism in poly (methyl
methacrylate)(PMMA) rods doped with C 540 dye and C 540:Rh.B dye mixture as a combination has been
investigated. When a polished slice of pure C 540 doped polymer rod was used side by side with a C540:Rh B
doped rod with acceptor concentration [A] = 7x10-4 m/l , we could notice more than 100% change in the
transmitted intensity along opposite directions at the C 540, Rh B emission and the excitation wavelengths . A
blue high bright LED emitting at a peak wavelength 465nm was used as the excitation source.
Radhakrishnan, P; Nampoori, V P N; Kailasnath, M; Nishant, Kumar; Bikas, Ranjan(PHOTONICS-2008: International Conference on Fiber Optics and Photonics, December , 2008)
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[-]
Abstract:
The direction dependant wavelength selective transmission mechanism in poly (methyl
methacrylate)(PMMA) rods doped with C 540 dye and C 540:Rh.B dye mixture as a combination has been
investigated. When a polished slice of pure C 540 doped polymer rod was used side by side with a C540:Rh B
doped rod with acceptor concentration [A] = 7x10-4 m/l , we could notice more than 100% change in the
transmitted intensity along opposite directions at the C 540, Rh B emission and the excitation wavelengths . A
blue high bright LED emitting at a peak wavelength 465nm was used as the excitation source.
Padmaja, G; Ravi Kumar, A V; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(IOP, 1993)
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Abstract:
Spatial and temporal analyses of the spectra of the laser induced plasma from a polytetrafluroethylene (PTFE) target obtained with the 1.06 mu m radiation from a Q-switched Nd:YAG laser have been carried out. The spatially resolved spectra of the plasma emission show that molecular bands of C2 (Swan bands) and CN are very intense in the outer regions of the plasma, whereas higher ionized states of carbon are predominant in the core region of the plasma emission. The vibrational temperature and population distribution in the different vibrational levels have been studied as a function of laser energy. From the time resolved studies, it has been observed that there exist fairly large time delays for the onset of emission from all the species in the outer region of the plasma. The molecular bands in each region exhibit much larger time delays in comparison to the ionic lines in the plasma.