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The article describes a newly discovered single-beam heterodyne Z-scan method, which is commonly being used for the measurement of the slow response nonlinear refraction of absorbers exhibiting excellent sensitivity. The different parasitic linear effects can be easily eliminated by increasing the sensitivity of the absorbers.

The measurements of the nonresonant nonlinear refractive index [n.sub.2] in antimony glasses at telecom wavelengths are determined. The measurements are performed using the Z-scan technique with a 130 fs pulsed laser operating at five wavelengths in the range of 1400-1600 nm and the results show that the glasses composition are very appropriate for ultrafast photonics at telecom wavelengths.

Author(s): R. Bartels [1]; S. Backus [1]; E. Zeek [1]; L. Misoguti [1]; G. Vdovin [2]; I. P. Christov [3]; M. M. Murnane [1]; H. C. Kapteyn (corresponding author) [1] [...]

The effect of temperature on the two-photon absorption cross section of azoaromatic chromophores is reported.

The Z-scan technique with 120 fs pulses is used to investigate the singlet excited state absorption spectra of tetrapyridyl and tetrasulfonatophenyl porphyrins. The singlet excited state absorption process is very fast and hence the porphyrins can be used in optical limiting devices to limit ultrashort laser pulses at the visible region.

Z-scan technique at 532 nm is used to investigate nonlinear absorption dynamics of Zn(super 2plus), Cu(super 2plus), Ni(super 2plus) tetrapyridyl porphyrins in chloroform/methanol solution. A marked difference is observed in the nonlinear absorption and excited-state dynamics of closed (ZnTPyP)- and open-shell metalloporphyrins((CuTPyP)and (NiTPyP)).

The degenerate nonlinear absorption spectrum was measured in the MEH-PPV/chloroform solution by using the Z-scan technique with femtosecond laser pulses. The competition between two-photon (2PA) and saturated absorption (SA) is explained with the help of energy-level diagrams.