Abstract

We have used HeNe laser light absorption to perform 2-D spatial mapping of hole-compensated aluminum (Al-h⁺) impurity sites produced during vacuum sweeping of crystalline quartz. Application of an electric field parallel to the optic axis can produce a hole⁽¹⁾ trapped at a non-bonding oxygen ion (AlO₄)° site. These hole-compensated Al-h⁺ sites introduce color center absorption. The electro-diffusion process (sweeping) is performed under elevated temperature and vacuum conditions. The diffusion process produces a time-dependent spatial distribution of the Al-h⁺ centers and associated A₁-band optical absorption which is coincident with the 633-nm-HeNe laser wavelength. Spatial variations in the A₁-band absorption for swept quartz and for quartz subjected to ionizing radiation are correlated with the observed⁽¹⁾ coloration. Devices fabricated from crystalline quartz with hole-compensated aluminum impurity sites are resistant to the effects of ionizing radiation. The 2-D mapping of optical absorption is compared to electron spin resonance (ESR) measurements of aluminum impurity concentration in samples of vacuum swept cultured quartz.

© 1987 Optical Society of America