We report mid-infrared (MIR) nonlinear absorption in As2S3 glasses which results from two-photon excitation of valence electron to the Urbach extension followed by strong linear absorption of excited states. The measured MIR nonlinear absorption can be 3 to 4 orders of magnitude stronger than the two-photon absorption in the near-infrared for similar laser intensities and does not result from c...

The molecular bases of Alzheimer disease and related neurodegenerative disorders are becoming better understood, but the means for definitive diagnosis and monitoring in vivo remain lacking. Near-infrared optical spectroscopy offers a potential solution. We acquired transmission and reflectance spectra of thin brain tissue slabs, from which we calculated wavelength-dependent absorption and redu...

Introduction: Minerals subjected to high shock pressures exhibit structural changes with increasing pressure (e.g., fractures, deformations, formation of diaplectic glass, and complete melting [1-6]). Petrologic and thermal infrared spectroscopic studies have shown that diaplectic glass (maskelynite) formation in feldspars occurs between ~25-45 GPa, while significant melting occurs above ~45 GP...

The hydrated dielectron is a highly correlated, two-electron, solvent-supported state consisting of two spin-paired electrons confined to a single cavity in liquid water. Although dielectrons have been predicted to exist theoretically and have been used to explain the lack of ionic strength effect in the bimolecular reaction kinetics of hydrated electrons, they have not yet been observed direct...

water content plays an important role in the process of plant photosynthesis and biomass accumulation. many methods have been developed to retrieve canopy leaf water content from remote sensing data. however, the validity of these methods has not been verified, which limits their applications. this study estimates the leaf water content (lwc) of winter wheat with three most widely used indexes:...

the use of low level laser to reduce pain, inflammation and edema, to promote wound, deeper tissues and nerves healing, and to prevent tissue damage has been known for almost forty years since the invention of lasers. this review will cover some of the proposed cellular mechanisms responsible for the effect of visible light on mammalian cells, including cytochrome c oxidase (with absorption pea...

Chemical contrast at subwavelength spatial resolution ~l/10! is achieved using a fiber-based, infrared near-field microscope, at 3 mm wavelength. Chemically amplified polymer photoresists ~poly~t-butylmethacrylate!!, patterned by ultraviolet radiation and 250 nm thick, are imaged using infrared ~IR! wavelengths situated around the OH stretch band of the polymer, a region sensitive to photochemi...

A series of near-infrared (NIR) electrochromic and electroluminescent polymers containing the pendant dinuclear ruthenium complexes were synthesized and characterized. All the polymers are near-infrared (NIR) electrochromic, displaying an intense absorption centered at 1600 nm upon oxidation to the mixed-valence state. Single-layer diode devices comprising a layer of the complex polymers sandwi...