Second-Harmonic and Sum-Frequency Imaging of Organic Nanocrystals with Photon Scanning Tunneling Microscope

Second-harmonic generation and sum-frequency generation with photon scanning tunneling microscopy and shear-force detection are used to map the nonlinear optical response and the surface topograph of N-(4-nitrophenyl)-(L)-prolinol crystals with a subdiffraction-limited resolution. The domain-size dependence of the spatial feature is obtained, which shows the local orientational distribution of the optical near field radiated by nonlinear nanocrystals and reveals the difference between nanoscopic and macroscopic second-order optical nonlinearities of molecular crystals

DNA-Ormocer based biocomposite for fabrication of photonic structures

We report microfabrication of high quality photonicstructures such as two-dimensional photonic crystals and beam splitters from a high DNA load, photosensitive Ormocer nanocomposite. This nanocomposite combines the high dye loading capacity of DNA with the photopatternability and hardness of the Ormocer. The fabrication is performed with the two-photon lithography method. Detailed studies of the deoxyribonucleic acid distribution in the fabricatedstructures are conducted with Raman microscopy. We also demonstrate that the deoxyribonucleic acid based nanocomposite films cast on glass substrates are of high enough quality to support amplified spontaneous emission from dyes intercalated in the deoxyribonucleic acid

Modified Z-scan techniques for investigations of nonlinear chiroptical effects

We present simple modifications of the classic Z-scan technique for the investigations of nonlinear chiroptical effects, i.e. nonlinear circular birefringence and two-photon circular dichroism. Two methods for studying these effects: a “polarimetric Z-scan” and a “polarization modulated Zscan” are described in detail. These techniques were applied to estimate the order of magnitude of the effects for several different materials

Nanoscopic Study of Second-Harmonic Generation in Organic Crystals with Collection-Mode Near-Field Scanning Optical Microscopy

Collection-mode near-field scanning optical microscopy (NSOM) is used to map nanoscopic second-harmonic generation (SHG) in N-(4-nitrophenyl)-(L)-prolinol crystals. A spatial resolution of 98 nm is achieved. Near-field polarization-dependent SHG measurement is performed, and a local effective SHG susceptibility of 224 ± 18 pm/V is obtained. © 2001 Optical Society of America

Cubic nonlinear optical effects in deoxyribonucleic acid (DNA) based materials containing chromophores

Third-order nonlinear optical properties were investigated for the system incorporating the Disperse Red 1 dye and the deoxyribonucleic acid - cetyltrimethylammonium complex (DNA-CTMA). The interaction of the dye with the DNA chains does not lead to major changes of the nonlinear optical effects due to the DR1 dye. Polarization dependences of the nonlinear absorption in this system reveal, however, some indications that the interactions may lead to ordering of the dye molecules against the DNA chains

A Decade of Poland-AOD Aerosol Research Network Observations

The Poland-AOD aerosol research network was established in 2011 to improve aerosol–climate interaction knowledge and provide a real-time and historical, comprehensive, and quantitative database for the aerosol optical properties distribution over Poland. The network consists of research institutions and private owners operating 10 measurement stations and an organization responsible for aerosol model transport simulations. Poland-AOD collaboration provides observations of spectral aerosol optical depth (AOD), Ångstrom Exponent (AE), incoming shortwave (SW) and longwave (LW) radiation fluxes, vertical profiles of aerosol optical properties and surface aerosol scattering and absorption coefficient, as well as microphysical particle properties. Based on the radiative transfer model (RTM), the aerosol radiative forcing (ARF) and the heating rate are simulated. In addition, results from GEM-AQ and WRF-Chem models (e.g., aerosol mass mixing ratio and optical properties for several particle chemical components), and HYSPLIT back-trajectories are used to interpret the results of observation and to describe the 3D aerosol optical properties distribution. Results of Poland-AOD research indicate progressive improvement of air quality and at mospheric turbidity during the last decade. The AOD was reduced by about 0.02/10 yr (at 550 nm), which corresponds to positive trends in ARF. The estimated clear-sky ARF trend is 0.34 W/m2/10 yr and 0.68 W/m2/10 yr, respectively, at TOA and at Earth’s surface. Therefore, reduction in aerosol load observed in Poland can significantly contribute to climate warming