Photoinduced Absorption and Pulsed Recording of Dynamic Holograms in Bismuth Silicate Crystals

Abstract

The dynamics of photoinduced absorption and holographic-grating recording in photorefractive crystals of bismuth silicate is studied. It is shown that, with the use of nanosecond laser pulses and of the intensity on the order of 1 MW/cm 2 or higher, the induced absorption due to population of the short-lived trapping levels, with characteristic relaxation times about several milliseconds or tens of milliseconds, is the case. Recording of dynamic holograms has been realized in these conditions in bismuth silicate crystals. Two mechanisms of holographic-grating recording, with the lifetimes differing by three orders of magnitude, are established. At relatively low intensities, about 1 MW/cm 2 or lower, the medium response is determined by a photorefractive mechanism of nonlinearity, with relaxation times of several seconds. At the intensities exceeding 5 MW/cm 2 , one can observe a fast (ms relaxation times) component that may be associated with population of the short-lived traps. It is shown that the contribution of each mechanism is greatly dependent on the intensity of laser radiation and, for the intensities above 10-15 MW/cm 2 , the short-lived traps having millisecond lifetimes play the decisive role.

Пространственно-Модуляционная Спектроскопия Полупроводниковых Материалов На Основе Динамических Решеток

“…Видно формирование как коротко-(сотни микросекунд), так и долгоживущих (секунды) решеток, причем с увеличением интенсивности вклад долгоживущих решеток уменьшается, а короткоживущих -увеличивается. Похожее поведение фотоиндуцированных динамических решеток в кристалле силиката висмута отмечалось в работе [6].…”

“…Анализ кинетики дифрагированного сигнала на тонких и объемных динамических решетках позволяет измерять время их жизни и определять параметры материалов, такие как термооптический коэффициент, температуропроводность, времена жизни свободных носителей заряда и ловушечных уровней в полупроводниках и фоторефрактивных кристаллах, время жизни возбужденного состояния активаторов лазерных сред и др. [4][5][6].…”

Phase and Structural Thermal Evolution of Bi–Si–O Catalysts Obtained via Laser Ablation

“…Among them are metallic Bi and Si, oxides SiO 2 and SiO x (non-stoichiometric), different crystallographic polymorphs of Bi 2 O 3 (α, β, γ, δ, ε), BiO 2 and BiO 1,5 , and, finally, bismuth silicates, in particular, Bi 2 SiO 5 (metasilicate), Bi 12 SiO 20 (sillenite), and Bi 4 (SiO 4 ) 3 (orthosilicate, or eulytite). The latter bismuth silicates (BSOs) are attractive materials for a number of applications, such as sensors [1], capacitors [2,3], nanothermometers [4,5], acoustic devices and optical devices [6,7], fuel-cells [8], spatial light modulators [9], holographic grafting recorders [10], etc. Moreover, Bi-Si-O based materials find their application as bioactive materials [11], luminescent materials [12,13], and photocatalysts [14,15].…”