Theoretical and experimental research on spectral performance and laser induced damage of Brewsterʹs thin film polarizers

Polarizers respectively with broad polarizing region bandwidth, large layer thickness error tolerance and high extinction ratio are designed and prepared. Transmittance spectra of the prepared samples are measured at Brewsterʹs angle, and the results show that different requirements can be fulfilled by optimized designs. Spectral performance of designs with higher layer thickness error tolerance coincides better with the theoretical spectra. Laser induced damage threshold of the prepared samples are evaluated. Electric field distribution, defect, film absorption, and damage morphology are investigated, and the results indicate that electric field distribution in high index layers is the main reason that causes the difference of laser induced damage threshold. For both p polarized and s polarized light, the lower the electric field peak value and the farther the layer, which has the strongest electric field away from air, the higher the laser induced damage threshold.