Ion beam induced changes of the refractive index of PMMA

Reflectivity modification of polymethylmethacrylate by silicon ion implantation

“…The spatial distribution (depth profile) and the possible material compaction of the ionmodified layer are also of importance in this case. The optical constants and their depth profiles in that layer within PMMA are functions of implantation ion energy and fluence [7][8][9][10]. Thus, the modification of these material characteristics by the Fig.…”

“…A reasonable assumption about the mechanism of the physico-chemical modification of Si + -implanted PMMA in this case is the break of the bonding arrangements of the polymer in the surface layer by the Si + ions and deposition of silicon. Some contribution of such a mechanism is not excluded, taking into account the significant role of the nuclear stopping of Si + ions during their implantation into PMMA according to the relatively high mass of silicon ion and its low energy of only 50 keV [7,15,16]. A similar broad ($180 nm fwhm) asymmetric PL band peaked near 600 nm (l ex = 488 nm) and red-shifted with ion fluence is known from PL measurements of Si + -implanted glass, the origin of which was attributed to the formation of amorphous Si [24].…”

“…According to data from [7,15], a significant contribution of nuclear interactions, collision damage at the end of the ion range, direct displacement of polymer atoms and even a real doping effect [16] can be expected under these conditions. In order to correlate the optical properties modification and structural changes of PMMA upon Si + ion implantation, the samples were characterized by photoluminescence (PL) and micro-Raman spectroscopy.…”

“…Being closely related to the complex refractive index of the material, the reflectivity undergoes significant changes by ion implantation or ion bombardment [12]. PMMA is known to be highly sensitive to accelerated ions [7,13], thereby used in the ion-beam lithography and UV photolithography. For example, masking media (UV-opaque PMMA films) have been produced by implantation of PMMA with 150-200 keV silicon ions [14].…”

“…Particularly, the ion-beam modified transparent polymers, like poly-(methyl methacrylate) (PMMA), are of special interest for micro-photonics, diffractive optics and non-linear optics [4][5][6]. Providing a unique way for selective and efficient modification of the refractive index of the surface layer [1,2,[7][8][9][10], the ion implantation has been employed to produce optical waveguiding structures in PMMA even by using ions at a relatively low energy of 100 keV [11].…”