Thermally induced laser pulsing to measure weak optical absorptions.
Intracavity thermal lensing has been used to convert a cw dye laser to pulsed operation. The pulse width is a measure of the absorptivity of the solution in the cell. Experimental data are presented to show how this technique can be used to measure the absorptivity of a pure solvent and the concentration of a solute. The absorptivities (base e) of water, CH(3)OH, CH(3)COCH(3), and CCl(4) were determined to be, respectively, (1.24 +/- 0.17) x 10(-3), (1.01 +/- 0.07) x 10(-3), (1.74 +/- 0.09) x 10(-4), and (3.95 +/- x(-6) cm(-1). For CCl(4) in a 10-cm sample cell, the minimum detectable absorptivity is ~4 x 10(-6) cm(-1).
Cremers
D A
DA
Keller
R A
RA