title: Infrared absorption nano-spectroscopy using sample photoexpansion induced by tunable quantum cascade lasers.
abstract: We report a simple technique that allows obtaining mid-infrared absorption spectra with nanoscale spatial resolution under low-power illumination from tunable quantum cascade lasers. Light absorption is detected by measuring associated sample thermal expansion with an atomic force microscope. To detect minute thermal expansion we tune the repetition frequency of laser pulses in resonance with the mechanical frequency of the atomic force microscope cantilever. Spatial resolution of better than 50 nm is experimentally demonstrated.
authors: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA.
authors: Feng
authors: F
authors: Lu
authors: Mikhail A
authors: MA
authors: Belkin
mesh_terms: D000042:Absorption; D003198:Computer Simulation; D004867:Equipment Design; D007834:Lasers; D054023:Lasers, Semiconductor; D008027:Light; D018625:Microscopy, Atomic Force / Q000379:methods; D036103:Nanotechnology / Q000379:methods; D011108:Polymers / Q000737:chemistry; D011789:Quantum Theory; D013053:Spectrophotometry / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods*; D055068:Terahertz Spectroscopy / Q000379:methods
chemical_list: D011108:Polymers