title: Concurrent polarization retrieval in multi-heterodyne scanning near-field optical microscopy: validation on silicon form-birefringent grating.
abstract: We demonstrate a concurrent polarization-retrieval algorithm based on a multi-heterodyne scanning near-field optical microscopy (MH-SNOM) measurement system. This method relies on calibration of the polarization properties of the MH-SNOM using an isotropic region of the sample in the vicinity of the nanostructures of interest. We experimentally show the effectiveness of the method on a silicon form-birefringent grating (FBG) with significant polarization diversity. Three spatial dimensional near-field measurements are in agreement with theoretical predictions obtained with rigorous coupled-wave analysis (RCWA). Pseudo-far-field measurements are performed to obtain the effective refractive index of the FBG, emphasizing the validity of the proposed method. This reconstruction algorithm makes the MH-SNOM a powerful tool to analyze concurrently the polarization-dependent near-field optical response of nanostructures with sub wavelength resolution as long as a calibration area is available in close proximity.
authors.affiliation: Optics and Photonics Technology Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Rue A. –L. Breguet 2, CH-2000 Neuchâtel, Switzerland. libo.yu@epfl.ch
authors.forename: L
authors.initials: L
authors.lastname: Yu
authors.forename: T
authors.initials: T
authors.lastname: Sfez
authors.forename: V
authors.initials: V
authors.lastname: Paeder
authors.forename: P
authors.initials: P
authors.lastname: Stenberg
authors.forename: W
authors.initials: W
authors.lastname: Nakagawa
authors.forename: M
authors.initials: M
authors.lastname: Kuittinen
authors.forename: H P
authors.initials: HP
authors.lastname: Herzig
mesh_terms: D000465:Algorithms; D001718:Birefringence; D004867:Equipment Design; D019544:Equipment Failure Analysis; D018625:Microscopy, Atomic Force / Q000295:instrumentation* / Q000379:methods; D018613:Microscopy, Confocal / Q000295:instrumentation* / Q000379:methods; D012031:Refractometry / Q000295:instrumentation*