Study of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>F</mml:mi></mml:math>-Center Formation in KCl on a Picosecond Time Scale

Abstract

We have measured the growth of $F$-band absorption at 532 nm in pure KCl following two-quantum band-gap excitation by a 266-nm pulse. The rise time at $T\ensuremath{\approx}25$ K is 11\ifmmode\pm\else\textpm\fi{}9 psec. Spectral measurements confirm attribution of the early absorption to $F$ centers. This absorption reflects the generation of new Frenkel defects with the $F$ center created directly in its electronic ground state.