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K: Fachverband Kurzzeitphysik
K 8: Laseranwendungen und Lasermaterialbearbeitung II
K 8.3: Talk
Thursday, February 28, 2013, 14:30–14:45, HS 4
Application of fs-laser Generated Nanogratings for Arbitrary Polarization Control — •Christian Vetter, Sören Richter, Felix Zimmermann, Matthias Heinrich, Felix Dreisow, and Stefan Nolte — Institute of Applied Physics, Friedrich-Schiller-Universität Jena
We report on the generation of fs-laser induced nanogratings in fused silica and their intrinsic form-birefringent behavior. Based on that birefringence, it is shown, that nanogratings allow for the fabrication of intricately shaped and locally varying wave plates. More sophisticated structures may be used for optical mode conversion and other promising applications.
Nanogratings are permanent refractive index modifications based on emerging sub-wavelength cavities inside the bulk material. The grating period scales with the employed laser wavelength and number of applied pulses. Moreover, the orientation of the grating planes is perpendicular to the electric field direction. Since the typical grating period is smaller than the wavelengths of the visible spectral range, nanogratings act as an effective medium with anisotropic optical properties. That allows the fabrication of three-dimensional birefringent components with locally varying optical properties. The resulting spatially variable states of polarization are of great practical importance for optical mode conversion, beam shaping, improved material processing and other fields of application.