Modifications of poled silicate glasses under heat treatment

Ellipsometry-based study of glass refractive index depth profiles obtained by applying different poling conditions

“…The appearance of the n(d) peak deserves to be discussed in more details. Similar peak in n(d) was found after poling of BK7 glass and attributing it with a pile-up K + ions [2]. There, the peak is approximately 0.002 higher than the refractive index of the untreated sample.…”

“…Ca and Mg pass a maximum before the decrease to a constant value. This corresponds to the drift of the lower mobility ions (Ca, Mg) and an increase of their concentration in the pile up region, observed by other authors as well [1,2,6,7,19]. Mg has a wide shoulder towards bulk possibly indicating two kinds of Mg species having different mobility.…”

“…A common technique involved to study depth profile of the poled glass composition is secondary ion mass spectrometry (SIMS). SIMS has confirmed diffusion of Na, Ca, Mg, Mn and K towards cathode, while Al concentration does not change [2,16,17,[19][20][21]. Due to their different mobility and formation of internal electric field, Ca and K concentrations form peaks, with Ca maxima closer to the anode treated surface.…”

“…Depletion of positive ions at one side and their accumulation at some depth are inducing a formation of an internal electric field. This field has permanent character, unless the sample is heated above the glass transition temperature [2]. The process of forming the internal electric field inside glass due to ion drift is called glass poling.…”

Second‐Order Optical Response in Electrically Polarized Sodo‐Niobate Amorphous Thin Films: Particularity of Multilayer Systems

“…The basic principle of this process is simple and has been applied to glasses to produce a SONL response since the beginning of the 1990s. [ 5 ] Thermal poling of a large variety of glass families has been examined, including all types of pure silica, [ 5–8 ] silicate, [ 9–12 ] phosphate, [ 13–16 ] germanate, [ 17,18 ] tellurite, [ 19–21 ] and chalogenide [ 22,23 ] materials, with this list being nonexhaustive. Various attempts have been made to develop optical devices relying on the SONL response of poled glasses with the glasses being either in the form of optical fibers [ 24,25 ] or in planar systems.…”