We report the impulsive generation of terahertz (THz) radiation with a field amplitude of more than 1.5 kV/cm at megahertz repetition rates, using an interdigitated photoconducting device. The approach provides an average THz power of 190 microW, corresponding to an optical-to-THz conversion efficiency of 2.5 x 10(-4). Optimum conditions are achieved when the excitation spot size is of the orde...

Single crystals of Ammonium acid phthalate have been grown using the slow evaporation technique. A single crystal of good quality was harvested in a period of 30 days. Different characterization studies were carried out for finding its suitability in device fabrications. The lattice parameters were found from single crystal X-ray diffraction analysis. The grown crystal crystallized under orthor...

We present a planar large-area photoconducting emitter for impulsive generation of terahertz sTHzd radiation. The device consists of an interdigitated electrode metal-semiconductor-metal sMSMd structure which is masked by a second metallization layer isolated from the MSM electrodes. The second layer blocks optical excitation in every second period of the MSM finger structure. Hence charge carr...

Nonequilibrium self-assembly of molecules holds a huge prospect as a tool for obtaining new-generation materials for future applications. Crystallization of neutral molecules within a supramolecular gel matrix is one example in which two nonequilibrium processes occur orthogonal to each other. On the other hand, electronically interacting donor-acceptor two-component systems are expected to for...

A novel scheme for the optical generation and coherent detection of tunable narrow-band far-infrared radiation in free space is described. This technique involves the optical heterodyning of two linearly chirped broadband pulses to produce a quasi-sinusoidal intensity modulation at tunable terahertz frequencies. The frequency content of the narrow-band terahertz radiation produced by mixing chi...

We demonstrate the recording of holograms and their nondestructive readout in a photorefractive polymer, using two-photon absorption. Sensitivity is provided by the excitation of the electroactive chromophore with femtosecond pulses, followed by charge injection into the photoconducting poly(N -vinylcarbazole) matrix. The holograms can be fully erased with a pulsed laser source but are insensit...