Chromophores optical sensors

Similarly, an anionic chromophore HC can also be used for designing optical sensors for cations, in this case, no extra anionic site (R ) is needed to maintain charge neutrality during the sensing. 

The anion optical sensor can also be fabricated with metalloporphyr-ins. For example, polymeric membranes doped with indium porphyrins and a lipophilic dichlorofluorescein derivative were shown to be very selective to chloride and acetate anions. The response mechanism is based on extraction of anions into the bulk organic film by indium porphyrins and a simultaneous coextraction of hydrogen ions. This results in protonation of the pH chromophore, and hence a change in the optical absorbance of the polymeric film. 

Dumont, M., Hosotte, S., Froc, G., and Sekkat, Z. (1994). Orientational manipulation of chromophores through photoisomerization. In Photopolymers and Applications in Holography, Optical Data Storage, Optical Sensors, and Interconnects. (R. A. Lessard, cd.), Proc. SPIE 2042,2-13. 

In the optical sensors based on crown ethers, chromophores or tiuorophores are usually employed to generate output signals. For example, the chromophoric dinitrophenyla-zophenyl group was introduced to the crown ether, as shown in Figure 3(a). In the presence of Li+, the chloroform-pyridine solution produced a color change from... 

The other sensor makes use of two dyes, bromophenol blue (BPB) and thymol blue (TB), to cover the range of interest26. The chromophores, immobilised on controlled pore glasses, are fixed at the end of plastic optical fibres. The distal end of the fibres is then heated and the CPGs form a very thin pH-sensitive layer on the fibre tips. The probe has four fibres (two for each chromophore) and its sketch is shown in Figure 5. A Teflon diffuse... 

This chapter provides an overview of the basic principles and designs of such sensors. A chemical sensor to detect trace explosives and a broadband fiber optic electric-field sensor are presented as practical examples. The polymers used for the trace explosive sensor are unpoled and have chromophores randomly orientated in the polymer hosts. The electric field sensor uses a poled polymer with chromophores preferentially aligned through electrical poling, and the microring resonator is directly coupled to the core of optical fiber. 

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