Surface metrology

Abstract

Some important types of instrumentation for measuring surfaces both past and present are reviewed. Exhaustive lists of instruments and performance are not presented; rather more emphasis is placed on the philosophy of measurement. An attempt is made to classify the surface features and also the function of surfaces as a prerequisite to measurement. It is revealed that, as the push towards miniaturization is being taken beyond the nanometrology scale, some theoretical restrictions are likely to be encountered.

A novel model of optimum nanofibre distribution in nanofibre scaffold structure by genetic algorithm method

“…Surfaces can be compared in terms of roughness parameters, including roughness average (Sa), root mean square roughness (Sq), average of the height difference between five highest peaks, the five lowest valleys (Sz), surface kurtosis (Sku) and surface skewness (Ssk). Roughness average (Sa) is a dispersion parameter defined as the mean of the absolute values of the surface departure above and below the mean plane within the sampling area [27].…”

“…Root mean square roughness (Sq), one of the dispersion parameters for characterising the surface roughness, is obtained by squaring each height value in the dataset and then taking the square root of the mean [27].…”

Investigation of some critical aspects of on-line surface measurement by a wavelength-division-multiplexing technique

“…The light from the laser diode is reflected by the FBG to form a reference fibre Michelson interferometer independent of the surface to be measured. This reference interferometer is stabilised by a servo feedback system to suppress fluctuation in output phase of the interferometer induced by environmental perturbation [8][9]. A dispersive optical probe is mounted on one arm of the interferometer.…”

“…In the last decade, a few investigations have been devoted to on-line surface measurement by using optical methods [9][10][11][12]. All of them were intended to carry out the measurements for surface profile rather than surface roughness.…”

Common path Fourier domain optical coherence tomography based on multiple reflections within the sample arm

“…This creates higher reflections off optical surfaces within the objective for near-infrared light (NIR). The second case is a Mireau interferometer widely used in surface metrology [26]. To the best of our knowledge, this is the first time it is applied to OCT. Setups presented have a merit in both FDOCT methods, namely spectrometer based and swept source based OCT, although we show results only for spectrometer based system.…”