Faraday-configured mode-locked p-Ge laser and p-Ge far-infrared amplifier

A solid-state broad-band amplifier of far-infrared radiation (1.5 - 4.2 THz) based on intersubband transitions of hot holes in p-Ge is demonstrated using two p-Ge active crystals, when one operates as an oscillator and one as an amplifier. A peak gain higher than usual for p-Ge lasers has been achieved using time separated excitation of the oscillator and amplifier. Active mode locking of the p-Ge laser has been achieved in the Faraday configuration of electric and magnetic fields with distinct advantages over Voigt geometry. The 200 ps pulses of 80-110 cm-1 radiation were achieved by local gain modulation from an applied rf electric field at the 454 MHz round trip frequency of the laser cavity

Single axial-mode selection in a far-infrared p-GE laser

Single axial-mode operation of the pulsed far-infrared p-Ge laser with an intracavity Fabry-Perot type frequency selector has been observed by means of Fourier-transform spectroscopy. A spectral resolution better than 1 GHz has been achieved on an ordinary continuous-scan spectrometer using the event-locked technique for pulsed emission sources. A laser active-cavity finesse of at least unity has been directly confirmed from the measured emission spectral width. Analysis of the envelope of the corresponding interferogram suggests that the finesse exceeds 10. © 2000 American Institute of Physic

High-resolution study of composite cavity effects for p-Ge lasers

The temporal dynamics, spectrum, and gain of the far-infrared p-Ge laser for composite cavities consisting of an active crystal and passive transparent elements have been studied with high temporal and spectral resolution. Results are relevant to improving the performance of mode-locked or tunable p-Ge lasers using intracavity modulators or wavelength selectors, respectively. It is shown that an interface between the active p-Ge crystal and a passive intracavity spacer causes partial frequency selection of the laser modes, characterized by a modulation of their relative intensities. Nevertheless, the longitudinal mode frequencies are determined by the entire optical length of the cavity and not by resonance frequencies of intracavity sub-components. Operation of the p-Ge laser with multiple interfaces between Ge, Si, and semi-insulating GaAs elements, or a gap, is demonstrated as a first step toward a p-Ge laser with an external quasioptical cavity and distributed active medi

Tan Divina Amazona : the Legend of Isabel the Catholic Queen in Luis Vélez de Guevara’s La serrana de la Vera

In La serrana de la Vera (1613), Luis Vélez de Guevara provides an updated take on the medieval serrana, a lustful and dangerous mountain woman. He sets her legendary actions during the reign of Isabel I of Castile, and the play follows the protagonist Gila’s degeneration from an impressively strong labradora to a demonic man-murderer who boasts of over two thousand kills. Critics have noted the strong affinity between Queen Isabel and the serrana Gila and have focused on the play as an exemplum for curbing female behavior that exceeds the norms imposed by a patriarchal society. While the play creates a mirroring effect whereby Gila adopts and emulates Isabel’s masculine traits, I maintain that Gila’s virile behavior and starry-eyed admiration of Isabel entail more than a warning for women; her portrayal questions and challenges Isabel’s legend as presented in writings and remembrances of the queen. At the heart of this play, beyond the ambiguous gender of Gila, is the playwright’s challenge to the official mythic construction of royal personas. Vélez de Guevara takes an already legendary serrana character from popular folklore and links her with the queen, emphasizing how Isabel’s history approximates and in many instances is indistinguishable from myth. La serrana de la Vera ends as a tragedy, thus emphasizing the untenability of Isabel’s dehumanizing legend

Localized sources of water vapour on the dwarf planet (1) Ceres

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