Dynamic optical filtering

Important features to consider are the ease of software use and the ability to change the optical filters depending upon the peak absorption and emission spectra of the labels used. The dynamic range and sensitivity of the readers are important factors that can affect the assay protocol. A protocol that is suitable for one type of reader may not work as well in a second type of reader due to variations in the optics resulting in differences in dynamic range and sensitivity. Sensitivity is important because it aids in the miniaturization of assays and helps reduce the amounts of expensive reagents required. The ability to detect small quantities of product in an enzyme reaction means that less enzyme will be required. 

A variety of devices have been designed by using transparent electro-optical ceramic materials, including variable optical attenuators (VOA), polarization controllers (PC), sinusoidal filters, dynamic gain flattening filters, tunable optical filters, and (2-switches, which have been described in detail in Ref. [129]. A brief description is given for some devices as follows. 

The present MCR analysis of the O3 pulse-photolytic reaction becomes an important basis for real-time monitoring of chemical dynamics of AOP in washing processes with compact FUV spectrophotometers using optical filters. 

The optical polarization anisotropy in GaN films with nonpolar orientations can be used for static as well as dynamic polarization filtering. Furthermore, a PS PD has been realized, which has been extended to a narrow-band photodetector by combining it with a polarization filter having the in-plane crystal structure rotated by 90°. The concept of polarization anisotropy has also been applied to achieve polarized emission in (In,Ga)N/GaN LEDs grown along nonpolar orientations. 

The PR effect was first observed in 1966 as an undesirable effect in an EO crystal, LiNb03 [1], It was soon realized that this effect is reversible and its PR mechanism was then identified [2,3], These PR materials can be applied to high-capacity optical memories, dynamic hologram formations, massive interconnections, high-speed tunable filters, and true-time relay lines for phase array... 

Sweat, J.A. and Wetzel, D.L. (2001) Near infrared acousto-optic tunable filter based instrumentation for the measurement of dynamic spectra of polymers. Rev. Sci. Instrum., 72 (4), 2153-8. 

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