Investigation of the dielectric, optical and photorefractive properties of Sb-doped Sn2P2S6 crystals

Abstract

International audienceIn this work we report results on electro-physical, optical and photorefractive investigations for Sb-doped Sn2P2S6 crystals. The crystals are obtained by two methods: the vapour-transport technique and the Bridgman technique using stoichiometric Sn2P2S6 composition with different amounts of antimony in the initial compound. The good optical quality of the crystals obtained with the Bridgman technique is underlined. The dependences of the photorefractive two-beam coupling coefficient and the grating build-up time are investigated at the wavelength of 633 nm. It is found that the sample doped with 1.5% of Sb is characterized by an optimal combination of the main photorefractive parameters exhibiting a fairly high two-beam coupling coefficient (up to 20 cm-1) and a short response time (1.3 ms) that is the shortest among all the previously studied Sn2P2S6 crystals in the red spectral region

Photoinduced EPR study of Sb2+ions in photorefractive Sn2P2SBrant1, Halliburton2, Basun3 et al. 2012Phys. Rev. BSelf Cite17170View full textAdd to dashboardCite

“…15,18 The EPR-observed photocharging of a significant amount of Sb 3+ to Sb 2+ (on the order of 10 18 cm −3 ) is caused when electrons are transferred from intrinsic photorefractive centers in the Sn 2 P 2 S 6 crystals. After being formed, the photogenerated Sb 2+ ions act as hole traps.…”

“…18 A significant increase in the photorefractive gain factor for red light correlates with the presence of this Sb-related optical absorption band and its associated photoconductivity. 15,18 More recently, preilluminated Sb-doped crystals have been shown to contain secondary photorefractive centers that affect the dynamics of the beam coupling and cause transient beam fanning. 20 Until the present study, no candidates for these Sb-related secondary centers have been identified.…”

“…[5][6][7][8][9][10][11][12][13] Specific dopants, such as Sb, Te, and Bi, are known to significantly affect the wavelength response and the speed of the photorefractive effect in the Sn 2 P 2 S 6 crystals. [14][15][16][17][18][19] Doping with Sb ions introduces a near-edge optical absorption band that shifts the onset of transparency to longer wavelengths (from about 530 nm for an undoped crystal to near 650 nm when the Sb doping level is 2%). 18 A significant increase in the photorefractive gain factor for red light correlates with the presence of this Sb-related optical absorption band and its associated photoconductivity.…”

“…[14][15][16][17][18][19] Doping with Sb ions introduces a near-edge optical absorption band that shifts the onset of transparency to longer wavelengths (from about 530 nm for an undoped crystal to near 650 nm when the Sb doping level is 2%). 18 A significant increase in the photorefractive gain factor for red light correlates with the presence of this Sb-related optical absorption band and its associated photoconductivity. 15,18 More recently, preilluminated Sb-doped crystals have been shown to contain secondary photorefractive centers that affect the dynamics of the beam coupling and cause transient beam fanning.…”

Light induced absorption and optical sensitizing of Sn 2 P 2 S 6 :Sb

“…At the same time, the photorefractive response of SPS is still inhibited by the space charge field limitation, a consequence of the insufficient effective trap density [5]. In part, the problem of insufficient effective trap density was solved by technological efforts: crystals deliberately doped during the growth procedure showed improved characteristics [3,6,7]. There remains, however, still much room for further improvement, until the fundamental limit for the gain factor is reached, which is defined by the largest Pockels tensor component of SPS.…”