To measure fluorescence with femtosecond resolution an all optical methode is needed. we use femtosecond up-conversion. Using the raw output from the Rega amplifier we external recompress the pulses, split 25:75 and generate 395 nm pulses as a weak pump beam. Samples are excited and the resultant emission is collected and focused onto a sum frequency BBO crystal along with the 75% 800 nm gating pulse. The resultant UV is filtered with a double monochromator (JY Gemmini) and measured using a solar blind PMT. Signals are recorded usinf gated single photon counting (Becker&Hickl). Our system currently has a 250 fsec cross corrolation resolution. Using this ultrafast fluorescence emission we study early time singlet exciton dynamics including hot emission and superfluorescence in solid samples.
Coherent Mira 900F Ti:Sapphire Coherent Verdi X pump laser Coherent Rega Ti:Sapphire amplifier Coherent
Jobin Yvon Gemmini double additive monochromator Electron tubes Solar blind photon counting PMT
Becker and Hickl PM400 gated photon counting card
Newport IMS 600 delay line Newport URM80 rotation stage
Cryomech ST405 3K pulse tube cryostat