Ultrafast Optoelectronics

THz Spectra for Some Bio-molecules

“…6 The configuration structure and molecular formula for glycine. calculation and normal mode analysis [36][37][38], as well as on the comparison with the recent results in literatures [1][2][3]18]. It is out of expectation and can not be understood in this moment that there are more spectral lines for glycine than that for alanine in the similar THz region observed in this experiment if one takes account to that the molecule of glycine Fig.…”

<title>Analysis of system trade-offs for terahertz imaging</title>

“…The PDA is typically a dipole antenna drawn on a semiconductor substrate, which radiates when a laser pulse enables a photocurrent pulse to flow across the biased semiconductor gap [32]. Although simple to construct, a PDA requires an ultrafast laser to activate, and femtosecond lasers are expensive.…”

“…For example, the most efficient dipole configuration emits an average of 3 mW of terahertz for 20 mW of excitation [36], whereas only 30 nW is typically generated from 175 mW of excitation with optical rectification [37]. The advantage of FSEOS lies in its bandwidth, which is limited not by the speed of the photocurrent pulse as in a PDA, but by the non-linear characteristics of the emitter crystal [32]. Terahertz pulses with wavelengths extending down to 7 mm have been generated [37].…”

Optoelectronic characterization of transmission lines and waveguides by terahertz time-domain spectroscopy

“…Optoelectronic techniques combining ultrafast laser pulses, photoconductive switching [1], electrooptic sampling [2], and very large scale integration (VLSI) lithography have enabled the generation and measurement of subps electrical pulses propagating as a single-mode excitation on coplanar transmission lines [1]- [5]. Besides their many applications for device characterization [1], [2], [6], these pulses can also be used to characterize the transmission line itself, by the powerful method of THz time-domain spectroscopy (THz-TDS) [7]- [9].…”

“…Besides their many applications for device characterization [1], [2], [6], these pulses can also be used to characterize the transmission line itself, by the powerful method of THz time-domain spectroscopy (THz-TDS) [7]- [9].…”