1. Fluorescence 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.

  2. Femtosecond 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 of spectrum.

    Transient absorption spectrometer could be modified easily for other experiments. For example, one can use it for the non-degenerate two-photon absorption measurements.

  3. Fluorescence life-time measurements

    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.

  4. 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.
  5. Absolute 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.
These experimental setups are available immediately or on the short notice.

E-mail: mikhailovsky@chem.ucsb.edu | Phone: (805) 893-2327