Abstract
The nonlinear transmission of 30-ps (FWHM) 0. 53- mu m pulses has been studied in narrowband interference filters. These filters consist of two high-low index lambda /4 stacks with a 2 lambda ZnSe spacer layer between. A reduction in transmission was observed with increasing irradiance. The bandgap of ZnSe (2. 67 eV) allows two-photon absorption (2PA) of 0. 53- mu m light. Excited-state carrier absorption in conjunction with the residual linear absorption may also be present. The change in transmission is greatly enhanced by the Fabry-Perot cavity. On resonance, the enhancement in internal irradiance I within the ZnSe is approx (1 plus R)/(1 minus R), ignoring linear absorption, where R is the stack reflectivity. 2PA also depends on I**2. The transmission of this filter as a function of angle from normal incidence is shown for both P and S polarizations for low and high incident irradiance levels. The peak transmission and width of the curve for S polarization are consistent with the expected higher reflectivities of the four-layer high-low lambda /4 stacks. The higher finesse for S polarization actually leads to a larger percentage change in transmission for S polarization than for P polarization, even though the peak transmission is considerably smaller.
| Original language | English |
|---|---|
| Title of host publication | Digest of technical papers: XV International Conference on Quantum Electronics |
| Publisher | Optical Soc of America |
| Pages | 60, 62 |
| ISBN (Print) | 936659513 |
| Publication status | Published - 1987 |
| Externally published | Yes |