Second harmonic generation analysis

Dadap J I, Hu X F, Russell N M, Ekerdt J G, Lowell J Kand Downer M C 1995 Analysis of second-harmonic generation by unamplified, high-repetition-rate, ultrashort laser pulses at Si(OOI) interfaces/ J. Selected Topics Quantum Electron 1 1145-55... 

The fundamentally important case p-nitroaniline (PNA), the high symmetry parent molecular unit of MNA, presents an excellent example for both experimental methodology and theoretical analysis. In the C 2 v symmetry for PNA and second harmonic generation, the measured principal component 3X is given by... 

In the following sections we will first in Section 2 briefly discuss the necessary background to understand optical activity effects in linear and nonlinear optics and to illustrate the similarities and differences between both types. In Section 3 we present a more thorough analysis of nonlinear optical effects in second-harmonic generation, both from a theoretical and an experimental point of view. Section 4 deals with experimental examples that illustrate the usefulness of nonlinear optical activity in the study of chiral thin films and surfaces. Finally, in Section 5 we give an overview of the role of chirality in the field of second-order nonlinear optics and show that chiral molecules can be useful for applications in this field. 

In addition to the indirect experimental evidence coming from work function measurements, information about water orientation at metal surfaces is beginning to emerge from recent applications of a number of in situ vibrational spectroscopic techniques. Infrared reflection-absorption spectroscopy, surface-enhanced Raman scattering, and second harmonic generation have been used to investigate the structure of water at different metal surfaces, but the pictures emerging from all these studies are not always consistent, partially because of surface modification and chemical adsorption, which complicate the analysis. 

Greenhalgh, C., Cisek, R., Prent, N., Major, A., Aus der Au, J., Squier, J., and Barzda, V. 2005. Time and structural image analysis of microscopic volumes, simultaneously recorded with second harmonic generation, third harmonic generation, and multiphoton excitation fluorescence microscopy. Proc. SPIE 5969 59692F1-F8. 

After an overview of the main papers devoted to chaos in lasers (Section I.A) and in nonlinear optical processes (Section I.B), we present a more detailed analysis of dynamics in a process of second-harmonic generation of light (Section II) as well as in Kerr oscillators (Section III). The last case we consider particularly in the context of coupled nonlinear systems. Finally, we present a cumulant approach to the problem of quantum corrections to the classical dynamics in second-harmonic generation and Kerr processes (Section IV). 

Both theoretical analysis and dipole moment measurements indicated that sulfonyl-substituted compounds may have ft coefficients similar in magnitude to their nitro analogues. Therefore, we have measured p for several sulfonyl- and nitro-substituted compounds using electric-field-induced second-harmonic generation method (EFISH) (11,25). In this experiment, one measures an effective third-order nonlinearity rEFISH for a solution containing the compound of interest, given by... 

Actually, it is very hard to determine whether the crystals (or solid) are doped in chiral or achiral. The space group can be determined by only X-ray crystallographic analysis. Now, we can conveniently survey the crystal from the measurement of CD spectra (KBr or nujor method)[8] or activity of SHG (Second Harmonic Generation). [9] However, sense of high accuracy is required for the use of both methods. When we could observe a Cotton effect from the CD spectra, the crystal system should be chiral. On the other hand, there are many examples of chiral crystals that exhibit quite a little Cotton effect. As a matter of course, it is also difficult to recognize chiral crystals when the enantiomeric purity is poor. 

In this chapter we deal primarily with experimental results that have been reported dealing with parametric interactions in nonlinear poled polymers, i.e. mostly on second harmonic generation in phase-matched configurations. Because the theoretical analysis associated with these processes has been known for some time and has been independently reviewed many times, we will only briefly overview these basics. Also, the polymeric materials developed for similar applications are reviewed in another section of this book and we refer the reader to that for details. 

Refs. [i] Hoke R (2008) Surface and interface analysis an electrochemists toolbox. Springer, Berlin [ii] Tadjeddine A, Peremans A (1998) Non-linear optical spectroscopy of the electrochemical interface. In Clark RJH, Hester RE (eds) Advances in spectroscopy (spectroscopy for surface science), vol. 26. Wiley, Chichester, p 159 [iii] Shen YR (1990) In Gutierrez C, Melendres C (eds) Spectroscopic and diffraction techniques in interfacial electrochemistry (NATO ASI series C, vol. 320). Kluwer, Dordrecht, p 281 [iv] Shen YR (1986) Applications of optical second-harmonic generation to surface science. In Hall RB, Ellis AB (eds) Chemistry and structure at interfaces. VCH, Deerfield Beach, p 151 [v] Williams CT, Beattie DA (2002) SurfSci 500 545... 

Refs. [i] Richmond GL, Robinson JM, Shannon VL (1988) Progr Surf Sci 28 1 [ii] Richmond GL (1991) Optical second harmonic generation as an in situ probe of electrochemical interfaces. In Bard A] (ed) Electroanalytical chemistry, vol. 17. Marcel Dekker, New York, p 87 [iii] Corn RM, Romagnoli M, Levenson MD, PhilpottMR (1984) / Chem Phys 81 4127 [iv] Georgiadis R, Richmond GL (1991) / Phys Chem 95 2895 [v] Holze R (2008) Surface and interface analysis an electrochemists toolbox. Springer, Berlin... 

Structurally, HMX exhibits conformational polymorphism, as demonstrated in Fig. 9.1. Brill and Reese (1980) analysed the relative stabilities of the a, p and 8 forms in terms of coulombic forces to interpret the thermophysical behaviour of the three forms. They concluded that the chair conformation found in the p modification is more stable than the chair-chair conformation in the other two forms. The relative stability to pyrolysis could also be accounted for by the analysis of the coulombic attractions and repulsions around the molecule in each of the modifications. More recently, Henson et al. (1999) have followed the change in second harmonic generation response during the jS -> 5 phase change, which has long been implicated in the thermal decomposition of HMX (Karpowicz and Brill 1982). 

Besides improving classical electrochemical methods, newly employed techniques such as second harmonic-generation and time-resolved fluorometry, with either control of the potential drop across the interface or fluctuation analysis, are promising in this respect. Also indispensable are further advances in molecular dynamics and statistical-mechanical treatments of structure and charge transfer at the ITIES. 

R. Srinivasan and LI. Suni, Kinetic analysis of Au deposition from aqueous HE onto Si(l 11) by surface second harmonic generation, J. Electrochem. Soc. 146, 570, 1999. 

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