Helium-neon lasers, wavelength range

This table gives the index of refraction of liquid water at atmospheric pressure, relative to a vacuum, at several temperatures and wavelengths. It is generated from the formulation in Reference 1, which covers a wide range of temperature, pressure, and wavelength. The wavelengths listed here correspond to prominent lines of cadmium (226.50 and 361.05 nm), potassium (404.41 nm), sodium (589.00 nm), Ne (632.80 nm, from a helium - neon laser), and mercury (1.01398 pm). 

Helium neon laser—A laser in which the active medium is a mixture of helium and neon its wavelength is usually in the visible range. 

The latex particle size was determined using a Brookhaven BI 90 particle size analyzer with a 5 mW helium-neon laser of 623.8 nm wavelength at room temperature. Prior to the analysis, the latexes were diluted with double-distilled deionized water to minimize the particle-particle interactions until the volume fractions of the particles were in the range of 0.01 to 0.1. An average hydrodynamic radius of latex particles (/in) was calculated from the intrinsic diffusion coefficient (Do) as... 

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