Radhakrishnan, P; Nampoori, V P N; Girijavallabhan, C P; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
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Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
Nampoori, V P N; Radhakrishnan, P; Girijavallabhan, C P; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
[+]
[-]
Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
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, January 13, 2006)
[+]
[-]
Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
Sheeba, Mavila; Thomas, Kannampuzha J; Rajesh, Mandamparambil; Nampoori, Vadakkedathu P N; Vallabhan, Chakkalakkal P G; Radhakrishnan, Padmanabhan(Optical Society of America, 2007)
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Abstract:
Multimode laser emission is observed in a polymer optical fiber doped with a mixture of Rhodamine 6G (Rh 6G) and Rhodamine B (Rh B) dyes. Tuning of laser emission is achieved by using the mixture of dyes due to the energy transfer occurring from donor molecule (Rh 6G) to acceptor molecule (Rh B). The dye doped poly(methyl methacrylate)-based polymer optical fiber is pumped axially at one end of the fiber using a 532 nm pulsed laser beam from a Nd:YAG laser and the fluorescence emission is collected from the other end. At low pump energy levels, fluorescence emission is observed. When the energy is increased beyond a threshold value, laser emission occurs with a multimode structure. The optical feedback for the gain medium is provided by the cylindrical surface of the optical fiber, which acts as a cavity. This fact is confirmed by the mode spacing dependence on the diameter of the fiber.
Ritty J, Nedumpara; Thomas, K J; Jayasree, V K; Girijavallabhan, C P; Nampoori, V P N; Radhakrishnan, P(Optical Society of America, July 20, 2007)
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Abstract:
The results of a brief investigation of the amplified spontaneous emission and lasing characteristics of Coumarin 540 dye in as many as ten different solvents are reported. It has been found that C 540 dye solutions contained within a rectangular quartz cuvette give laser emission with well resolved equally spaced modes when pumped with a 476 nm beam. The modes were found to originate from the subcavities formed by the plane-parallel walls of the cuvette containing the high-gain medium. While the quantum yield remains a decisive factor, a clear correlation between the total width of the emission spectra and the refractive indices of the solvents of the respective samples has been demonstrated. The well-resolved mode structure exhibited by the emission spectra gives clear evidence of the lasing action taking place in the gain medium, and the number of modes enables us to compare the gain of the media in different samples. A detailed discussion of the solvent effect in the lasing characteristics of C540 in different solutions is given.