Gargi Sharma

Generation of 1.5 µJ single-cycle terahertz pulses by optical rectification from a large aperture ZnTe crystal

We demonstrate the generation muJ-level, single-cycle terahertz pulses by optical rectification from a large-aperture ZnTe single crystal wafer. Energies up to 1.5 muJ per pulse and a spectral range extending to 3 THz were obtained using a 100 Hz Ti:sapphire laser source and a 75-mmdiameter, 0.5-mm-thick, (110) ZnTe crystal, corresponding to an average power of 150 muW and an energy conversion efficiency of 3.1 x 10(-5). We also demonstrate real-time imaging of the focused terahertz beam using a pyroelectric infrared camera.

Nonlinear ultrafast modulation of the optical absorption of intense few-cycle terahertz pulses in n-doped semiconductors

We use an open-aperture

Generation of Intense Terahertz Radiation via Optical Methods

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Terahertz pulse induced intervalley scattering in photoexcited GaAs

scan technique to show how intense few-cycle terahertz pulses can experience a nonlinear bleaching of absorption in an

Concurrent field enhancement and high transmission of THz radiation in nanoslit arrays

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Improved terahertz two-color plasma sources pumped by high intensity laser beam

-doped semiconductor due to terahertz-electric-field-driven intervalley scattering of electrons in the conduction band. Coherent detection of the transmitted terahertz pulse wave form also allows the nonlinear conductivity dynamics to be followed with subpicosecond time resolution. Both the

Carrier density dependence of the nonlinear absorption of intense THz radiation in GaAs

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Terahertz detection using spectral domain interferometry

scan and time-domain results are found to be in agreement with our theoretical analysis.

Time-Resolved Terahertz Spectroscopy of Free Carrier Nonlinear Dynamics in Semiconductors

The development of new sources in the terahertz (THz) spectral region has attracted much attention over the past 20 years. In particular, the last three years have seen a surge of new laser-based techniques for generating intense, few-cycle THz pulses in the microjoule energy range, thus paving the way to the study of the nonlinear optical properties of various materials at THz frequencies. Simultaneously, innovative solutions for broad-band THz detection were found, allowing one to sense matter in the THz range with an unprecedented time resolution. In this paper, we will attempt to give a review of the properties and characteristics of the recently developed intense THz sources, with a particular eye on their potential application in ultrafast THz nonlinear spectroscopy.

Self-referenced spectral domain interferometry for improved signal-to-noise measurement of terahertz radiation

Nonlinear transient absorption bleaching of intense few-cycle terahertz (THz) pulses is observed in photoexcited GaAs using opticalpump--THz-probe techniques. A simple model of the electron transport dynamics shows that the observed nonlinear response is due to THz-electric- field-induced intervalley scattering over sub-picosecond time scales as well as an increase in the intravalley scattering rate attributed to carrier heating. Furthermore, the nonlinear nature of the THz pulse transmission at high peak fields leads to a measured terahertz conductivity in the photoexcited GaAs that deviates significantly from the Drude behavior observed at low THz fields, emphasizing the need to explore nonlinear THz pulse interactions with materials in the time domain.