RESUMO
Birefringence is shown to be induced in polysilane thin films by the process of chain scission induced by nonlinear absorption at visible wavelengths. This writable birefringence is easy to control and can be used for the fabrication of birefringent gratings and other optical devices.
RESUMO
Frequency-modulation spectroscopy was employed successfully to measure the Doppler-free absorption and dispersion signals originating from several two-photon transitions in (85)Rb and (87)Rb. The two-photon cross section of the hyperfine transition 5S(1/2) (F = 2) ? 5D(5/2) (F = 4) in (87)Rb was determined to be sigma((2)) asymptotically equal to 4 x 10(-20) cm(4)/W. The transition isotope shift (TIS) of the transition 5S(1/2) ? 5D(5/2) between (87)Rb and (85)Rb was found to be Deltanu(TIS) = +166 +/- 2 MHz.
