Electro-optic polymers for wideband THz-applications

1. film ITO 1 cm glass THz beam pellicle [110] polymer [1-10] polarizer ZnTe c(2) material compensator polarizer Electro-optic polymers for wideband THz-applications Alexander Sinyukov, Peter Lindahl, Joey French, and L. Michael Hayden, Department of Physics, University of Maryland, Baltimore County, Baltimore, MD 21250 Meng He and Robert J. Twieg, Department of Chemistry, Kent State University, Kent, OH 44242 Materials Optical rectification EO polymer properties • high electro-optic coefficient (r33 = 50 pm/V @ 785 nm) • no phonon absorption !! • phase matching ?? • n = 1.75 @ 800 nm,static dielectric constant, e ~ 3 • 50-500 mm thick • versatility • cheap ! Electro-optic polymer composites are fabricated from mixtures of nonlinear optical chromophore guests and polymer hosts (PMMA, APC). Lemke-e m =8.31 Debye,  =12165 esu Wideband, sub-ps visible light generates far-IR femtosecond pulses via three wave mixing amongst the input frequencies. Electro-optic detection Predicted frequency response DCDHF-MOE-V m = 12.3 Debye,  = 18576 esu. mb/M = 1.9 x Lemke • phonon absorption gaps in ZnTe, GaP response •  very thin crystals required for wideband response •  no resonances in polymer composites •  coherence length tuning possible in polymers •  polymers have larger response (rpolymer > rcrystal) 13 mm thick scaling DCDHF-6-V m= 12.7 Debye, = 18640 esu m/M = 1.7 x Lemke The THz beam provides the electric field which modulates the index of refraction in the c(2) material. Balanced detection increases the signal-to-noise ratio. Wideband emission THz-performance of EO polymer Experimental setup