Fast photorefractive response in B_12SiO_20 in the near infrared

Abstract

The polarization self-modulation effect was applied for effective measurement of the characteristic response time of nominally pure Bi(12)SiO(20) (BSO) at wavelengths of 810 and 980 nm. Owing to oxygen deficiency in the crystal lattice, the BSO crystals showed unusual photorefractive sensitivity and remarkable operation speed in the near-infrared spectral region. A response time of 130 ms was measured at 810 nm, and a response time of 540 ms was measured at 980 nm, with incident intensities of 110 and 200mW/cm(2), respectively. To our knowledge, this is the first experimental evidence of a subsecond response in the infrared for a nonsemiconductor photorefractive material.

Quasi-nonvolatile storage in Ru-doped Bi_12SiO_20 crystals by two-wavelength holography

“…Optically pumping the electrons with gating light is recognized method to enhance the near-infrared properties of sillenites [8]. Some authors assigned the observed transient character during holographic recording to simultaneous electron-hole gratings competition [9,10]. Generally, the anti-site Bi defect (known as Bi 3+ Si + h center upon illumination assuming n-type photoconductivity), is identified as the main photorefractive defect in sillenite structure.…”

“…Later on, improved NIR recording and extended lifetime has been achieved in un-doped BTO due to the hole-based complementary grating after green light pre-exposure [9]. At the same time, a modification of sillenite's structure by reduction/oxidation treatments [10] or by adding suitable dopants have been done [11,12]. For example, Ru addition shows prospective features for energy transfer and twobeam coupling efficiency enhancement [13].…”

“…the Eqs. (6)-(10) into Eqs. (1)-(5), where the equations for the zero -and first order terms are expressed as:…”

Two-wavelength holographic recording in ruthenium-doped Bi<inf>12</inf>SiO<inf>20</inf> crystal at near-infrared spectral range

“…They find wide applications in real-time holography, optical information processing, holographic interferometry, …etc [1][2][3]. Recently, special attention is focused on near infrared (NIR) sensitivity improvement [4][5][6][7], which is of essential technological interest since it allows utilization of cheap diode lasers in photorefractive devices development for optical fiber communication as well as of particular importance for non-destructive biological object testing.…”

“…Two possible ways to extend the sensitivity to the NIR spectral range were demonstrated by affecting the growth conditions of sillenite crystals to increase oxygen defects concentration [4][5][6], as well as by introducing suitable doping elements into the crystal structure. We reported that Ruthenium (Ru) is an appropriate dopant, which significantly improves the NIR sensitivity of Bi 12 TiO 20 (BTO) [7].…”