Nonlinear Optical Study of Si Epitaxy

1986 ◽  
Vol 75 ◽  
Author(s):  
T. F. Heinz ◽  
M. M. T. Loy ◽  
S. S. Iyer
Keyword(s):  
Nonlinear Optical ◽  
Room Temperature ◽  
Second Harmonic ◽  
Optical Technique ◽  
Optical Study ◽  
Harmonic Response ◽  
Reconstructed Surface ◽  
Epitaxial Crystal Growth ◽  
Si Epitaxy

AbstractThe applicability of the nonlinear optical technique of surface second-harmonic generation to in-situ studies of epitaxial and non-epitaxial crystal growth of centrosymmetric materials is demonstrated. In measurements of the deposition of atomic Si on Si(111)-7×7 surfaces, the (anisotropic) second-harmonic response is seen to be sensitive to the ordering of fractional monolayers of adatoms. For deposition on a substrate held at room temperature, the second-harmonic data are consistent with the formation of a disordered adlayer on top of the original reconstructed surface. The results of real-time measurements of the thermal annealing of disordered Si adlayers of monolayer thickness are also presented.

POLAR MICRO STRUCTURES OF THE B2- AND B4-PHASES OF BENT-SHAPED LC-MOLECULES RESOLVED BY NONLINEAR OPTICAL MICROSCOPY

2006 ◽  
Vol 15 (02) ◽  
pp. 287-302 ◽  
Author(s):  
OMAR G. MORALES-SAAVEDRA ◽  
ANTAL JÁKLI ◽  
GERD HEPPKE ◽  
HANS J. EICHLER
Keyword(s):  
Liquid Crystalline ◽  
Nonlinear Optical ◽  
Room Temperature ◽  
Applied Research ◽  
Second Harmonic ◽  
Polar Order ◽  
Scanned Images ◽  
Micro Structures ◽  
Maker Fringes

A nonlinear optical (NLO) microscope has been developed based on recording the second harmonic generation (SHG) signals of the B 2- and B 4-phases of bent shaped liquid crystalline (LC) materials. We observed that the microstructures of the polar order can be accurately characterized by 2D scanned images implementing this device. Specifically, we have investigated two bent-core compounds, which have either B 4 or B 2 phases at room temperature and exhibit SHG activity. The NLO microscope was calibrated according to the Maker-fringes method allowing the in situ evaluation of the relative SHG efficiency. The developed NLO microscopy device may serve as an important tool to characterize liquid crystalline features at a microscopic scale for both fundamental and applied research.

scholarly journals In situ second-harmonic generation mediated photodynamic therapy by micelles co-encapsulating coordination nanoparticle and photosensitizer

RSC Advances ◽  
2017 ◽  
Vol 7 (82) ◽  
pp. 52125-52132 ◽  
Author(s):  
Xuyang Zhou ◽  
Yang Chen ◽  
Jian Su ◽  
Xiaohe Tian ◽  
Yonghuang Luo ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Property A

NIR-PDT strategy was introduced by employing a nonlinear optical conveyor bearing strong second-harmonic generation (SHG) property. A biocompatible micellic system co-delivered the conveyor and photosensitizer for in situ NIR-PDT.

PRELIMINARY OPTICAL STUDY ON ER FLUIDS

1994 ◽  
Vol 08 (20n21) ◽  
pp. 2921-2933 ◽  
Author(s):  
L. W. ZHOU ◽  
J. F. YE ◽  
R. B. TAO ◽  
Y. TANG ◽  
J. F. PENG ◽  
...  
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
Electric Fields ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Optical Response ◽  
Optical Study ◽  
Solid States ◽  
Linear And Nonlinear ◽  
Er Fluids

Linear and nonlinear optical study on electrorheological (ER) fluids is reported. The ER fluids under the investigation were glass beads, zeolite and ferroelectrics. The linear optical response of some ER fluids showed sharp changes near critical electric fields. An enhancement of electric field induced second harmonic generations (EFISH) was observed as the function of E2, where E is the external electric field. The said enhancement is considered to be corresponding to a modulation of the material's refractive index associated with the electric field induced polarization of the delocalized electrons. The enhanced nonlinear optical response on the transition between liquid and solid states can be related to the phase transition in ER fluids.

Growth of Co Nanoclusters on SiC Honeycomb Templates

2004 ◽  
Vol 818 ◽  
Author(s):  
Wei Chen ◽  
Kian Ping Loh ◽  
Hai Xu ◽  
A.T.S. Wee
Keyword(s):  
Substrate Temperature ◽  
Room Temperature ◽  
Scanning Tunneling ◽  
Nucleation Process ◽  
Desorption Rate ◽  
Tunneling Microscopy ◽  
Scale Range ◽  
Reconstructed Surface ◽  
Substrate Temperatures

AbstractA honeycomb-like SiC reconstructed surface with regular, periodic porosity in the nano-scale range has been used as an effective template for the formation of monodispersed Co nanoclusters. In-situ scanning tunneling microscopy (STM) was used to study the nucleation process of the Co nanoclusters on this template. The deposition of Co at different substrate temperature was investigated by STM. It is found that the failure in the deposition of Co nanoclusters on the SiC honeycomb template with substrate temperatures higher than room temperature (RT) might be due to the high desorption rate of the adsorbed Co atoms.

GROWTH AND CHARACTERIZATION OF A SEMIORGANIC NLO MATERIAL: L-HISTIDINE BARIUM CHLORIDE DIHYDRATE

2016 ◽  
Vol 2 (1) ◽  
pp. 26-30
Author(s):  
Beena T R
Keyword(s):  
Nonlinear Optical ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Second Harmonic ◽  
Barium Chloride ◽  
Nonlinear Optical Material ◽  
Solvent Evaporation Method ◽  
X Ray ◽  
Chloride Dihydrate

L-Histidine Barium Chloride dihydrate (LHBC), a semi organic nonlinear optical material was grown from aqueous solution by slow solvent evaporation method at room temperature.  The LHBC crystals were characterized by X-ray powder diffraction analysis.  The presence of functional groups was identified through Fourier Transform Infrared Spectroscopy.  Thermogravimetric and Differential Thermal Analysis confirm that the crystal is stable up to 269oC.  The mechanical properties of the grown crystals have been studied using Vickers microhardness test.  The second harmonic generation behavior of LHBC crystal was tested by Kurtz-Perry powder technique.

In Situ Measurement of the Second Harmonic Signal of Adsorbing Nonlinear Optical Ionically Self-Assembled Monolayers.

2001 ◽  
Vol 707 ◽  
Author(s):  
C. Brands ◽  
P.J. Neyman ◽  
M.T. Guzy ◽  
S. Shah ◽  
K.E Van Cott ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Salt Water ◽  
Harmonic Signal ◽  
Deionized Water ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Second Harmonic Signal

ABSTRACTIonically self-assembled monolayers (ISAMs) have recently been shown to spontaneously exhibit a polar ordering that gives rise to substantial second order nonlinear optical response. The deposition of ISAMs has been studied in situ via second harmonic generation. This is a particularly sensitive probe of the growth of nanometer-thick films since the centrosymmetry of the immersion solutions, the substrate, and the container yields no SHG contribution from these bulk components. Upon immersion in the NLO-active polyelectrolyte solution, the SHG rises sharply over the first minute. When a film is immersed into salt water, the SHG decreases significantly only to be restored when the salt solution is replaced with deionized water.

Nonlinear Optical Microscopy for Imaging Patterned Self-Assembled Monolayers

1996 ◽  
Vol 440 ◽  
Author(s):  
L. Smilowitz ◽  
Q.X. Jia ◽  
X. Yang ◽  
D.Q. Li ◽  
D. McBranch ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Self Assembled Monolayers ◽  
Optical Technique ◽  
Nonlinear Optical Microscopy ◽  
Surface Sensitivity ◽  
Surfaces And Interfaces ◽  
Assembled Monolayers ◽  
Potential Applications ◽  
Self Assembled

AbstractWe have used the inherent surface sensitivity of second harmonic generation (SHG) to develop an instrument for nonlinear optical (NLO) microscopy of surfaces and interfaces. This optical technique is ideal for imaging nanometer thick self-assembled monolayers (SAM's) which have been patterned using photolithographic techniques. In this paper we demonstrate the application of SHG microscopy to patterned SAM's of the noncentrosymmetric molecule calixarene and discuss other potential applications for this new technique.

Synthesis, Crystal Structure, Luminescence, and Nonlinear Optical Properties of 2-[(E)-[[4-[2-(4-Methoxyphenyl)ethynyl]phenyl] imino]methyl]-4- [(E)-phenyldiazenyl]phenol

2020 ◽  
Vol 17 (8) ◽  
pp. 618-623
Author(s):  
Sagar Subhash Mohite ◽  
Aditya Babasaheb Patil-Deshmukh ◽  
Sanjay Shamrao Chavan
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Nonlinear Optical ◽  
Room Temperature ◽  
Second Harmonic ◽  
Monoclinic Structure ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Shg Efficiency ◽  
Room Temperature Luminescence

2-((E)-((4-((4-methoxyphenyl)ethynyl)phenyl)imino)methyl-4-((E)phenyldiazenyl)phenol (1) have been synthesized and characterized. X-ray single crystal diffraction study of the compound 1 reveal a monoclinic structure. Room temperature luminescence is observed for 1 in CH2Cl2 solution due to π* → π transition. The SHG efficiency by Kurtz powder technique indicating the compound 1 displayed the second harmonic generation (SHG) property.

POLAR ORDERING IN THERMOTROPIC MESOGENS RESOLVED BY SCANNING NLO MICROSCOPY

2006 ◽  
Vol 15 (04) ◽  
pp. 431-446 ◽  
Author(s):  
OMAR G. MORALES-SAAVEDRA ◽  
JÁKLI ANTAL ◽  
HEPPKE GERD ◽  
EICHLER HANS J.
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Applied Research ◽  
Second Harmonic ◽  
Polar Order ◽  
Microscopic Scale ◽  
Shg Efficiency ◽  
Scanned Images ◽  
Maker Fringe

A nonlinear optical (NLO) microscope has been developed based on recording the second harmonic generation (SHG) signals of the B 2- and B 4-phases of bent-shaped liquid crystalline (LC) materials. We observed that the microstructures of the polar order can be accurately characterized by 2D scanned images implementing this device. Specifically, we have investigated two bent-core compounds, which have either B 4 or B 2 phases at room temperature and exhibit SHG activity. The NLO microscope was calibrated according to the Maker fringe method allowing the in situ evaluation of the relative SHG efficiency. The developed NLO-microscopy device may serve as an important tool to characterize liquid crystalline features at a microscopic scale for both, fundamental and applied research.

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