Abstract
The photosensitive properties of a centrosymmetric gadolinium gallium garnet crystal doped with calcium are investigated at room temperature. Elementary holograms can be recorded over a wide range of wavelengths in the visible spectral range. The photosensitive properties are studied experimentally using beam coupling and angular response experiments. Mixed absorption and refractive-index gratings are observed and their amplitudes and relative phases determined. Moreover, the candidate centers that are responsible for the photorefractive effect are discussed.
Highlights
Gadolinium gallium garnet (Gd3Ga5O12, GGG) belongs to the most perfect materials that are grown in large quantities with a dislocation density of less than 3/cm 3 [1]
From previous work it is known that the bands B1, B2 and B3 originate from intrinsic point defects and charge compensation which produce complex color centers (CCC) and F-centers [27, 24, 28, 14]
The calcium ion itself does not induce absorption bands, but its addition results in a charge imbalance
Summary
Gadolinium gallium garnet (Gd3Ga5O12, GGG) belongs to the most perfect materials that are grown in large quantities with a dislocation density of less than 3/cm 3 [1]. Small amounts of calcium oxide are usually added to the melt during crystal growth in order to avoid screwed growth of rare-earth GGG crystals. This helps in growing large single crys-. Doping with small amounts of calcium results in degradation of laser performance because of optical loss by irradiation induced color centers [11]. Any photochromic effect is related to an induced refractive-index change through the Kramers-Kronig relation. GGG is a possible candidate for a photorefractive material suitable for information storage, provided that induced refractive index changes are high enough. The aim of this Letter is to demonstrate, to investigate, and to characterize the photochromic and the photorefractive properties of GGG:Ca at room temperature by means of holographic techniques
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
