Rajesh, M; Geetha, K; Sheeba, M; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(Society of Photo-Optical Instrumentation Engineers, July , 2006)
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Abstract:
The length-dependent tuning of the fluorescence spectra of a dye doped polymer fiber is reported. The fiber is pumped sideways and the fluorescence is measured from one of the ends. The excitation of a finite length of dye doped fiber is done by a diode pumped solid state laser at a wavelength of 532 nm. The fluorescence emission is measured at various positions of the fiber starting from a position closer to the pumping region and then progressing toward the other end of the fiber. We observe that the optical loss coefficients for shorter and longer distances of propagation through the dye doped fiber are different. At longer distances of propagation, a decrease in optical loss coefficient is observed. The fluorescence peaks exhibit a redshift of 12 nm from 589 to 610 nm as the point of illumination progresses toward the detector end. This is attributed to the self-absorption and re-emission of the laser dye in the fiber.
Sathy, P; Reji, Philip; Nampoori, V P N; Vallabhan, C P G(Springer, June , 1990)
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Abstract:
Experimental method for measuring photoacoustic(PA) signals generated by a pulsed laser beam in liquids is described. The pulsed PA technique is found to be a convenient and accurate method for determination of quantum yield in fluorescent dye solutions. Concentration dependence of quantum yield of rhodamine 6G in water is studied using the above method. The results indicate that the quantum yield decreases with increase in concentration in the quenching region in agreement with the existing reports based on radiometric measurements.
Girijavallabhan, C P; Radhakrishnan, P; Nampoori, V P N; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, February 24, 2004)
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Abstract:
We report the position dependent tuning of fluorescence emission from
rhodamine 6G doped polymethylmethacrylate film waveguide using a side
illumination technique. The transmitted fluorescence as a function of the
distance from the point of illumination is measured by translating the
waveguide horizontally across a monochromatic light source. This technique
has been utilized to characterize the optical loss in dye doped waveguides.
We observe that the optical loss coefficients for shorter and longer distances
of propagation through the dye doped waveguide are different. At longer
distance of propagation a decrease in optical loss coefficient is observed