ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
A microinterferometric backscatter detector (MIBD) has been developed to perform subnanoliter volume refractive index measurements using a simple, folded optical train based on the interaction of a laser beam and a fused silica capillary tube. Positional changes of the interference pattern extrema (fringes) allow for the determination of Δn at the 10−7 level, corresponding to 5.3 pmole or 0.48 ng of solute, when thermal noise is controlled at 8×10−3 °C. MIBD is relatively path-length insensitive for capillaries ranging in inner diameter from 75 to 775 μm, allowing a large range of detection volumes, from 350 pL to 40 nL, to be produced. A theoretical model of the microinterferometric backscatter detector has also been developed and evaluated and has been found to be in agreement with experimental data. This model indicates increased sensitivity of the instrument as the wavelength of the probe beam and the wall thickness of the capillary tube are reduced. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1150675
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