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D-band Time Resolved Millimeter Wave Conductivity experimental setup using ELVA-1 SGMW-D-PLL becomes operational at North Carolina Central University


After receiving funding from the UNC General Administration for this experimental facility NCCU obtained the probe signal sweeper from ELVA-1 through Gilland Electronics, CA.

The pump involves a Q-switched diode-pumped solid state laser (Coherent make "Helios" 532-1.5-50, 532 nm with spatial mode: TEM00 M2 < 1.25) and The D-band sweeper generator is used in cavityless, contactless quasi optical pump-probe setup.  The TRMMWC is enabling measurements of the frequency dependent photoconductivity directly based on electronic population resulting in complete decay curve with single excitation pulse. The carrier mobility is extracted through fitting into the models.  Frequency selectivity of existing low noise backward wave oscillator (BWO) mm wave probe will enable us to obtain complete decay curve with single excitation pulse thereby resolving sub-ns to milliseconds time range. Initial studies would use the wide tuning for sensitivity analysis and to study the photo-conductance decay in c-Silicon, P3HT, and P3HT:PBCM blends as a function of the mm wave probe frequency. In addition, there are plans to use a wide variety of pump source including an in-house 40 fs, 2mJ/pulse output at 800 nm at a repetition rate of 1 kHz laser source. This is a unique facility created at NCCU as no other time-resolved transient photoconductivity data have been reported using D-band probe signature.