945 research outputs found
Heidt, Robert H.
No full textColor photographic portrait depicting Robert H. Heidt, former Professor of Law.
Artist: Thomas Casalini
Date: 2013
Plate on frame reads: Robert J. Heidt, Professor of Law, 1982-2013
Location: Law School, Baier Hall, Room 125https://www.repository.law.indiana.edu/portraits/1045/thumbnail.jp
Mid-IR coherent supercontinuum generation in all-solid step-index soft glass fibers
No full textWe numerically demonstrate that normal dispersion femtosecond pumping of tailored soft glass step-index fibers can generate highly coherent mid-IR supercontinuum light with two octaves bandwidth, suitable for recompression to few-cycle pulse durations
The FORS deep field
No full textDedicating a major fraction of its guaranteed time, the FORS consortium started investigating a FORS Deep Field, which also contains a known QSO at z = 3.36. The FORS Deep Field (FDF) was imaged in UBgRIz with the FORS instrument at the ESO VLT1 as well as in J and Ks with the ESO NTT. Covering an area 6 - 8 times larger as the HDFs but nearly as deep in the optical it is one of the largest deep fields up to date to investigate, e.g., the galaxy evolution from present up to z similar to 5. An overview about the field selection, planned projects, the status and first imaging and spectroscopic results is given
Dataset for 'Limits of coherent supercontinuum generation in normal dispersion fibers'
No full textData for figures in A. Heidt et al., 'Limits of coherent supercontinuum generation in normal dispersion fibers' J. Opt. Soc. Am. B, 34(4), 764-775 (2017) https://doi.org/10.1364/JOSAB.34.000764.
Paper abstract: We study the largely unexplored transition between coherent and noise-seeded incoherent continuum generation in all-normal dispersion (ANDi) fibers and show that highly coherent supercontinua with spectral bandwidths of one octave can be generated with long pump pulses of up to 1.5 ps duration, corresponding to soliton orders of up to N=600. In terms of N, this corresponds to an approximately 50 times increase of the coherent regime compared to anomalous dispersion pumping. In the transition region between coherent and incoherent spectral broadening, we observe the manifestation of nonlinear phenomena that we term incoherent cloud formation and incoherent optical wave breaking, which lead to a gradual or instantaneous coherence collapse of supercontimuum (SC) spectral components, respectively. The role played by stimulated Raman scattering and parametric four-wave mixing during SC generation in ANDi fibers is shown to be more extensive than previously recognized: their nonlinear coupling contributes to the suppression of incoherent dynamics at short pump pulse durations, while it is responsible for non-phase-matched parametric amplification of noise observed in the long pulse regime. We further discuss the dependence of SC coherence on fiber design, and present basic experimental verifications for our findings using single-shot detection of SC spectra generated by picosecond pulses. This work outlines both the further potential as well as the limitations of broadband coherent light source development for applications such as metrology, nonlinear imaging, and ultrafast photonics, among others.</span
Reconceiving the State: morals, markets, and state regulation of assisted reproductive technologies
No full textAssisted reproductive technologies (ARTs), defined as technologies that bring together human gametes for the purposes of reproduction and regenerative research, have enabled new life for those expanding their families, as well as those looking to treat degenerative diseases. As meanings of life have shifted in an era of evolving reproductive technology, the state has new opportunities to intervene, mediate, and prohibit the use of ARTs in the United States. In light of the moral and instrumental ways to understand ARTs and the social implications of ART practices, what is the role of the state in ART oversight? Moreover, how does issue framing of ARTs impact legislative outcomes? Using egg donation as a particular site of morals and markets, I investigate these question through the legislative activity on egg donation at the state level, as well as the public policy making processes about egg donation. Given the empirical and theoretical gaps in ART scholarship about state-level legislation in the US in the contemporary period, this dissertation aims is to answers these research questions through original data on various kinds of ART legislation between 1990 and 2010, at the state level. Employing hazard analysis of egg donation legislation between 1998 and 2008 in 49 states, this project advances the argument that state-level legislative activities on egg donation are vibrant, and increased by scientific stakeholders in ARTs, as well as the presence of women in politics and economic life. Looking closer at cases of egg donation legislation in case studies of California, New York, Arizona, and Louisiana, I find that legislators frame egg donation as moral and instrumental social issues—with varying degrees of legislative success. I argue that state-level oversight has problematic implications for the concept of stratified reproduction and suggest applying the equal liberty principle to ART policymaking. Finally, I argue that the absence of political debate—particularly the absence of feminist voices—warrants new political solutions to increase democratic discourse on ART issues.Ph. D.Includes bibliographical referencesby Erin Allyson Heidt-Forsyth
High power diode-seeded fiber amplifiers at 2µm - from architectures to applications
No full textWe review recent advances in the development of high power short- and ultrashort pulsed Thulium-Doped Fiber Amplifier (TDFA) systems seeded by semiconductor laser diodes at wavelengths around 2µm. The diode-seeding and the master oscillator power amplifier (MOPA) design allow for the construction of extremely versatile laser systems that can operate over wide ranges of peak power, pulse energy and repetition rate in the ultrashort picosecond to the long nanosecond pulsed regimes. We present a record peak power of 130kW and pulse energy of 5µJ in picosecond mode, while demonstrating user-defined pulse-shaping capabilities at millijoule pulse energy levels in the nanosecond regime from essentially the same amplifier system. The system architecture as well as important design and power scaling considerations are discussed in detail. Additionally, we highlight recent results in the application of these MOPA systems and their high performance TDFA stages in such diverse application areas as next generation telecommunication networks, mid-infrared supercontinuum generation and mid-infrared gas detection in hollow-core photonic bandgap fibers
The QSO HE1013-2136 (z = 0.785): Tracing the ULIRG-QSO connection towards large look-back times?
No full textDeep BRIH-images as well as long-slit spectra taken with the ESO-2.2m and VLT-telescopes of the QSO HE1013-2136 (z = 0.785) are presented. They show the QSO apparently in the last phase of a 1:3 merger. Two tidal tails extending 9" and 3.5" (68 and 26 kpc) and several condensations within 3.5" projected distance are clearly detected. The latter could be companion galaxies to the QSO or debris of a merger remnant. Due to the complexity of the system, the morphology of the host galaxy is not well constrained, however, the host galaxy seems to be as bright as 2--3 L*. The I- and H-band images of HE1013-2136 show remarkable differences, which are hard to asses. At present it cannot be ruled out that one of the merging galaxies formed a ring-like structure. The spectrum of the QSO shows it to be an extreme Fe II emitter, which is typical for IR-bright QSOs. At least one of the nearby condensations is most likely at the same redshift as the QSO, however, no signs of (post)starburst activity seen in many nearby interacting QSOs are detected. HE1013-2136 shows many similarities to the low-redshift (z = 0.29) intermediate QSO PG 1700+518 and could thus be a unique probe of the ULIRG-QSO connection at large look-back times
PKS 0537-441: Extended [O II] emission and a binary QSO?
No full textWe present high-resolution imaging and low-resolution spectroscopy of the BL Lac object PKS 0537-441 (z = 0.893) and its environment carried out with the ESO-NTT and VLT telescopes. The observations were designed to clarify, whether the properties of PKS 0537-441 are affected by gravitational microlensing due to the claimed detection of a galaxy along the line-of-sight to the BL Lac, or whether PKS 0537-441 and its environment act as a lensing system itself, as suggested by the detection of several closeby companion galaxies with similar morphologies close to PKS 0537-441. Our observations show that neither case seems to be likely. Within our images we did not find a galaxy along the line-of-sight to the BL Lac as claimed previously. In addition, our spectroscopy shows that none of the four closest companion galaxies (including one new detection by us) is at high redshift. Instead, two of the four nearby companion galaxies to PKS 0537-441 are within 200 km s-1 of the systemic velocity of the BL Lac (z = 0.892 and 0.895, respectively). The third companion galaxy is at higher redshift (z = 0.947). The fourth companion galaxy shows evidence of Mg II absorption redwards of its systemic velocity and is perhaps a mini low-ionization BAL QSO at z = 0.885. If the latter can be confirmed, PKS 0537-441 is the first BL Lacertae object being a member of a binary Quasar. While we do not find (micro)lensing effects important for this source or its environment, our observations revealed a highly interesting feature. We detected extended [O II] emission in the off-nuclear spectrum of PKS 0537-441, which is most likely due to photoionization from the active nucleus, although we can not rule out the possibility that the extended emission is due to jet-cloud interaction with the counterjet of PKS 0537-441. According to our analysis of the photometric data, PKS 0537-441 seems to be located in a cluster environment as rich as Abell type 0-1. This is supported by the detection of four galaxies in the field with similar redshifts as the BL Lac (Delta z < 0.002). However, we serendipitously found even more galaxies at somewhat higher redshifts (z = 0.9-1). Thus, PKS 0537-441 might be located in front of a galaxy cluster at somewhat higher redshift or even be part of a large-scale structure with an extension towards the BL Lac.
Based on observations collected with the VLT-UT1 on Cerro Paranal (Chile) and the NTT on La Silla (Chile) operated by the European Southern Observatory in the course of the observing proposals 64.P-0230 and 66.B-0125
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