Femtosecond Blue Continuum Generation and its Application to the Time-Resolved Study of Mn2+ Emission in Mn-Doped ZnS Nanocrystals

Abstract

Recently, the achievement of high quantum efficiency light emission from semiconductor nanocrystals using transition metal doping was reported1 in the ZnS:Mn system. While this system is of considerable interest both scientifically (physics of low dimensional structures) and technologically (fast, high speed phosphors), the excitation dynamics in doped nanocrystals are still not well understood. In order to probe such a system on the picosecond or sub-picosecond time scale, a tunable ultrafast UV source is required. We have developed such a source by using the frequency-doubled output of a 250kHz Ti:sapphire regenerative amplifier2 to produce the blue continuum.