Transient excited singlet state absorption in POPOP and dimethyl POPOP

Rao, Y.V. Chalapati; Venkateswarlu, Putcha; George, M. C.; Jagannath, H.; Chakrapani, G.

doi:10.1016/0584-8539(88)80236-8

Cited by 4 publications

(2 citation statements)

References 17 publications

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“…This value was 8 times larger than that of ground-state absorption saturation. POPOP dyes are excited to the S1 states by 355-nm light 22 and the molecules in S1 states are excited to the S3 states by 532-nm light. 22 Although the lifetime of the highly excited state is unknown for POPOP, it is generally expected to be less than several picoseconds for such dye molecules in a liquid solution at room temperature.…”

Section: Enhancement Of the Ptl Signal By The Second-pump Pulsementioning

confidence: 99%

“…POPOP dyes are excited to the S1 states by 355-nm light 22 and the molecules in S1 states are excited to the S3 states by 532-nm light. 22 Although the lifetime of the highly excited state is unknown for POPOP, it is generally expected to be less than several picoseconds for such dye molecules in a liquid solution at room temperature. We concluded that there is no simple relation between the τeff values and the lifetimes of the ground and excited states, and that it is necessary to evaluate the saturation threshold experimentally, although the saturation threshold is one of the decisive factors to achieve a higher gain.…”

Section: Enhancement Of the Ptl Signal By The Second-pump Pulsementioning

confidence: 99%

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Photothermal Lensing Signal Enhancement by the Transient Absorption of Photoexcited States in Liquid Solutions

Harata

Yamaguchi

2000

ANAL. SCI.

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A two-color double-pulse excited photothermal lensing measurement was performed to investigate a signal enhancement owing to transient absorption by the excited states of solute molecules in liquid solutions. A colinear, mode-mismatched configuration with a continuous-wave probe laser at 633 nm was adapted with a focused pump pulse (6.9 ns, 355 nm) and a sequentially incident softly focused second-pump pulse (7.2 ns, 532 nm). The signal-intensity dependence on the energies of the pump and the second-pump pulses was measured for 1.0 µM solutions of 2,2′-p-phenylenebis(5-phenyloxazole) in 1-butanol and anthracene in ethanol. A signal enhancement was observed for both solutions. The signal intensity under certain conditions was one order higher than that expected from ground-state absorption. A discussion was made on determination of the absorption coefficient of the transient species and on the absorption saturation of the ground and excited states.

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Section: Enhancement Of the Ptl Signal By The Second-pump Pulsementioning

confidence: 99%

Section: Enhancement Of the Ptl Signal By The Second-pump Pulsementioning

confidence: 99%