Amplifiers of free-space terahertz radiation

Wave and Mode Interaction in Overmoded High-Power Amplifiers of Short-Wavelength Radiation (from W-band up to THz)

Detection of freely propagating terahertz radiation by use of optical second-harmonic generation.

We report the application of electric-field-induced optical second-harmonic generation as a new technique for measuring the field of freely propagating terahertz radiation. Using silicon as the nonlinear medium, we demonstrate subpicosecond time resolution and a sampling signal that varies linearly with the terahertz electric field. This approach, which is attractive for centrosymmetric media, ...

Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae.

Broadband horn antennae are presented that efficiently couple terahertz radiation between sub-wavelength metal-metal waveguides and free space. Sub-picosecond terahertz pulses were coupled into and out from sub-wavelength parallel-plate waveguides by using the horn antennae in a terahertz time-domain spectrometer. Monolithic antennae were fabricated at the facets of metal-metal terahertz quantu...

Ultrafast and nonlinear spectroscopy of semiconductors with small energy photons

Ultrashort pulses of intense, coherent, and tunable far-infrared and mid-infrared radiation, achievable with freeelectron lasers and optical parametric amplifiers, provide unique opportunities to investigate low energy dynamics in solids. This paper reviews our recent experiments on bulk and quantum-confined semiconductors using such radiation. These experiments include: far-infrared spectrosco...

Novel sources and detectors for coherent tunable narrow-band terahertz radiation in free space

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...