Long-wave infrared super-resolution wide-field microscopy using sum-frequency generation

• Main Authors: Caldwell, J.D (Author), De Pas, M. (Author), Gewinner, S. (Author), Lu, G. (Author), Niemann, R. (Author), Paarmann, A. (Author), Schöllkopf, W. (Author), Wasserroth, S. (Author), Wolf, M. (Author)
• Format: Article
• Language: English
• Published: American Institute of Physics Inc. 2022
• Subjects: Infrared devices; Infrared radiation; Interferometry; Localised; Nanostructures; Optical resolving power; Phonons; Photons; Proof of concept; Silicon compounds; Spatial resolution; Spectral range; Sum frequency generation; Superresolution; Super-resolution microscopy; Surface phonon-polaritons; Wide-field; Wide-field microscopies
• Online Access: View Fulltext in Publisher

 Super-resolution microscopy in the visible is an established powerful tool in various disciplines. In the long-wave infrared (LWIR) spectral range, however, no comparable schemes have been demonstrated to date. In this work, we experimentally demonstrate super-resolution microscopy in the LWIR range (λ I R ≈ 10 - 12 μm) using IR-visible sum-frequency generation. We operate our microscope in a wide-field scheme and image localized surface phonon polaritons in 4H-SiC nanostructures as a proof-of-concept. With this technique, we demonstrate an enhanced spatial resolution of ∼ λ I R / 9, enabling to resolve the polariton resonances in individual sub-diffractional nanostructures with sub-wavelength spacing. Furthermore, we show that this resolution allows us to differentiate between spatial patterns associated with different polariton modes within individual nanostructures. © 2022 Author(s).