Optical resonance spectroscopy

Fig. 43. The apparatus used by T aflin and Davis (1990) to study the bromination of an olefin droplet by optical resonance spectroscopy. Reprinted with permission from J. Aerosol Sci. 21, 73-86, Taflin, D. C., and Davis, E. J., Copyright 1990, Pergamon Press pic.

Although optical resonance spectroscopy is suitable for studying chemical reactions involving two reactants and a single product, it cannot be extended to more than two or three components because one cannot interpret the resonance spectrum uniquely to obtain the composition from the refractive index. Raman spectroscopy is an attractive alternative approach. 

Woolley RG (1982) Natural Optical Acitivity and the Molecular Hypothesis. 52 1-35 Wiithrich K (1970) Structural Studies of Hemes and Hemoproteins by Nuclear Magnetic Resonance Spectroscopy. 8 53-121... 

U. Kunz, A. Katerkamp, R. Renneberg, F. Spener, and K. Cammann, Sensing fatty acid binding protein with planar and fiber-optical surface plasmon resonance spectroscopy devices. Sens. Actuators B 32, 149-155 (1996). 

The goal of this chapter will be to provide an overview of the use of planar, optically resonant nanophotonic devices for biomolecular detection. Nanophotonics23 24 represents the fusion of nanotechnology with optics and thus it is proposed that sensors based on this technology can combine the advantages of each as discussed above. Although many of the issues are the same, we focus here on optical resonance rather than plasmonic resonance (such as is used in emerging local SPR and surface-enhanced Raman spectroscopy-based biosensors). 

Freely suspended liquid droplets are characterized by their shape determined by surface tension leading to ideally spherical shape and smooth surface at the subnanometer scale. These properties suggest liquid droplets as optical resonators with extremely high quality factors, limited by material absorption. Liquid microdroplets have found a wide range of applications for cavity-enhanced spectroscopy and in analytical chemistry, where small volumes and a container-free environment is required for example for protein crystallization investigations. This chapter reviews the basic physics and technical implementations of light-matter interactions in liquid-droplet optical cavities. 

The new techniques of phosphorescence-microwave multiplet resonance spectroscopy with optical detection have been reviewed by El-Sayed and Kwiram Such exciting experiments as the optical detection on electron-nuclear double resonance (ENDOR) and of electron-electron double resonance (EEDOR) in zero magnetic field have been achieved, and it is certain that much detailed knowledge concerning the phosphorescent states will evolve from this field. 

The reduction of obtainable light-pulse durations down to subpicosecond pulses (halfwidth about 10 sec) allows fast transient phenomena which were not accessible before to be studied in the interaction of light with matter. One example is the extension of spin echoe-techniques, well known in nuclear-magnetic-resonance spectroscopy, to the photon echoes in the optical region. 

Optical sensors have the advantage of an easily measured signal that can be seen by the naked eye in some cases. Optical detection methods include fluorescence, surface plasmon resonance spectroscopy, Raman, IR, and chemiluminescence (Fabbrizzi and Poggi 1995 deSilva et al. 1997). However, the fabrication and development of optical MIP sensors requires that a colored, emissive, or fluorescent monomer... 

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