ABSTRACT
An interferometric method to monitor the thinning process of vertical soap films from a water solution of surfactant materials is reported. Raw data maps of optical path difference introduced by the film are obtained by conventional phase shift interferometry. Off-line re-processing of such raw data taking into account the layered structure of soap films leads to an accurate measurement of the geometrical thickness. As an example of data acquisition and processing, the measuring chain is demonstrated on perfluoropolyether surfactants; the section profile of vertical films is monitored from drawing to black film state, and quantitative data on the dynamics of the thinning process are presented. The interferometric method proves effective to the task, and lends itself to further investigate the physical properties of soap films.
Subject(s)
Ethers/chemistry , Fluorocarbons/chemistry , Soaps/chemistry , InterferometryABSTRACT
A model for the optical path difference introduced by a soap bubble in transmission is described. The model is then used with interferometric data to solve for the fringe order, and to define a procedure to extract the global film thickness in presence of turbulence flows occurring during the drainage process due to gravity. Experimental results on soap bubbles examined in single-pass phase-shift interferometry are presented.
ABSTRACT
Diode pumped zig-zag slab lasers are widely adopted for continuous-wave high power or pulsed high energy applications. Recently [J. Eur. Opt. Soc.-Rapid 6, 11041 (2011)] we started to investigate a new thin slab format in which pumping radiation input is obtained through the thin lateral faces (edge pumping) and the beam propagation takes place bouncing on these same lateral faces ("edge zig-zag"). We report on the optimized operation of a ceramic Nd:YAG laser, based on this geometry, extracting 230 W at a 43% output power to diode power conversion efficiency. Thorough investigation of the thermal lens effect allows us to analyze the optical cavity and thus to define the main aspects limiting the present laser configuration.
ABSTRACT
Cases of long-term deformation of fused silica flats are reported. The phenomenon is detected at the scale of the nanometer, and exhibits a time constant of the order of 9 years. The observed deformation appears related to gravity and constraints, but a change of physical properties locally resulting in non-homothetic behavior is also hypothesized.
