setups are available immediately or on the short notice.
excitation via two-photon absorption
This technique is employed to measure two-photon absorption cross-section
in materials with high fluorescence efficiency. The setup utilizes the
output of Ti:Sapphire femtosecond laser to excite flurophores via the
two-photon absorption in the spectral range 690-960 nm.
transient absorption spectroscopy
Transient absorption spectroscopy enables one to study energy relaxation
and charge transfer processes in various materials with sub-100 femtosecond
resolution. In these experiments, hot charge carriers are photogenerated
in the sample by the intense pump pulse. Their relaxation is monitored
by probing absorption changes with the second optical pulse (probe).
In our transient absorption spectrometer, femtosecond white continuum
is used as a probe radiation. Its broad-band spectrum enables one to
monitor transient absorption dynamics over the entire visible range
Transient absorption spectrometer could be modified easily for other
experiments. For example, one can use it for the non-degenerate two-photon
This is a modified version of old system which used pulsed Nd:YAG laser.
Now, it can be used with several laser systems and utilizes digital
oscilloscope to convert the data into the digital format. Works perfect
on the microsecond time-scale where traditional time-correlated technique
suffers from low signal/noise ratio.
Time-correlated photon counting*
Time-correlated photon counting (TCSPC) is used for time-resolved
studies of emission processes. In our facility, it is used for
measurements of ultrafast fluorescence decay in various materials. Use
of microchannell plate photomultiplier tube and specialized counting
computer board allows one to record emission transients with 40
picosecond resolution. In order to achieve high temporal resolution,
samples are excited by sub-100 fs pulses from Ti:Sapphire laser.
*MCP PMT and TCSPC computer board are kindly provided by Professor
G. Strouse and are not OCF property.
quantum yield measurements in solid state films and solutions
This setup uses integrating sphere and calibrated photodetector for
the quantum efficiency measurements in solid state films and solutions
of fluorophores. Unlike traditional techniques, it does not require
calibrated reference sample.