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"Lanterns"
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Coherent Imaging with Photonic Lanterns
Photonic lanterns (PLs) are tapered waveguides that gradually transition from a multimode fiber geometry to a bundle of single-mode fibers (SMFs). They can efficiently couple multimode telescope light into a multimode fiber entrance at the focal plane and convert it into multiple single-mode beams. Thus, each SMF samples its unique mode (lantern principal mode) of the telescope light in the pupil, analogous to subapertures in aperture masking interferometry (AMI). Coherent imaging with PLs can be enabled by the interference of SMF outputs and applying phase modulation, which can be achieved using a photonic chip beam combiner at the backend (e.g., the ABCD beam combiner). In this study, we investigate the potential of coherent imaging by the interference of SMF outputs of a PL with a single telescope. We demonstrate that the visibilities that can be measured from a PL are mutual intensities incident on the pupil weighted by the cross correlation of a pair of lantern modes. From numerically simulated lantern principal modes of a 6-port PL, we find that interferometric observables using a PL behave similarly to separated-aperture visibilities for simple models on small angular scales (<λ/D) but with greater sensitivity to symmetries and capability to break phase angle degeneracies. Furthermore, we present simulated observations with wave front errors (WFEs) and compare them to AMI. Despite the redundancy caused by extended lantern principal modes, spatial filtering offers stability to WFEs. Our simulated observations suggest that PLs may offer significant benefits in the photon-noise-limited regime and in resolving small angular scales at the low-contrast regime.
Journal Article
Pumpkin day!
A boy and his family visit a pumpkin patch, where they ride on a cart, see animals, and pick out a pumpkin that's just right for carving.
Book
2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments
Photonic technologies offer numerous functionalities that can be used to realize astrophotonic
instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large
Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a
complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical
advantages for instrument development, including extreme miniaturization when operating at the
diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the
small footprint, and high replicability offering significant cost savings. Numerous astrophotonic
technologies have been developed to address shortcomings of conventional instruments to date,
including for example the development of photonic lanterns to convert from multimode inputs to
single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the
atmosphere, complex beam combiners to enable long baseline interferometry with for example,
ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers.
Despite these successes, the facility implementation of photonic solutions in astronomical
instrumentation is currently limited because of (1) low throughputs from coupling to fibers,
coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling
to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient
integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas
that need further development. We outline the challenges and advances needed across those areas
covering design tools, simulation capabilities, fabrication processes, the need for entirely new
components, integration and hybridization and the characterization of devices. To realize these
advances the astrophotonics community will have to work cooperatively with industrial partners
who have more advanced manufacturing capabilities. With the advances described herein,
multi-functional integrated instruments will be realized leading to novel observing capabilities for
both ground and space based platforms, enabling new scientific studies and discoveries.
Journal Article
Little Boo
A pumpkin seed tries unsuccessfully to be scary until it grows into a pumpkin and Halloween arrives.
Book
Eocene lantern fruits from Gondwanan Patagonia and the early origins of Solanaceae
The nightshade family Solanaceae holds exceptional economic and cultural importance. The early diversification of Solanaceae is thought to have occurred in South America during its separation from Gondwana, but the family’s sparse fossil record provides few insights. We report 52.2-million-year-old lantern fruits from terminal-Gondwanan Patagonia, featuring highly inflated, five-lobed calyces, as a newly identified species of the derived, diverse New World genus Physalis (e.g., groundcherries and tomatillos). The fossils are considerably older than corresponding molecular divergence dates and demonstrate an ancient history for the inflated calyx syndrome. The derived position of these early Eocene fossils shows that Solanaceae were well diversified long before final Gondwanan breakup.
Journal Article
The Creeps. 3, The Curse of the Attack-O-Lanterns
The Creeps are in trouble, again. When rule breaking during one of their investigations lands the detectives in \"service detention,\" the four friends find themselves lugging pumpkins off a foreclosed pumpkin patch. To thank them for their service, Sheriff Obie allows each Creep to take home a pumpkin to carve into a jack-o-lantern. Bad idea. Once carved, the jack-o-lanterns come to life--and attack everyone within reach! It turns out the pumpkins came from a cursed patch, and to stop the Attack-o-Lanterns from destroying their town, the Creeps will have to team up with the patch's unpleasant owner, Old Lady Bitterwood, who happens to be a witch.
Book
Air-Hole-Assisted Photonic Lanterns
Exploring innovative approaches to enhance the performance of photonic lanterns is greatly valuable. In this paper, we first propose an air-hole-assisted pure silica-based capillary (AHC), featuring a single ring of embedded air holes. As a result, the PL based on the AHC exhibits good performance, successfully exciting LP01, LP11a & LP11b, LP21a & LP21b, LP02, and LP31a & LP21b modes. The average mode loss, mode-dependent loss, and maximum crosstalk are 0.08 dB, 0.04 dB, and −27.2 dB, respectively. In fact, the overall performance of the proposed AHC-based PL is on par with that of the traditional PL. Furthermore, an error analysis is provided to confirm the feasibility of our approach. The AHC-based PLs possess high numerical apertures and are expected to enable high spatial resolution imaging in optical imaging.
Journal Article
A Million Pictures
Slides for the magic or optical lantern were a major tool for
knowledge transfer in the second half of the 19th and early 20th
centuries. Schools, universities, the church and many public and
private institutions all over the world relied on the lantern for
illustrated lectures and demonstrations. This volume brings
together scholarly research on the educational uses of the optical
lantern in different disciplines by international specialists,
representing the state of the art of magic lantern research today.
In addition, it contains a lab section with contributions by
archivists and curators and performers reflecting on ways to
preserve, present and re-use this immensely rich cultural heritage
today.
Authors of this collection of essays will include Richard
Crangle, Sarah Dellmann, Ine van Dooren, Claire Dupré La Tour,
Jenny Durrant, Francisco Javier Frutos Esteban, Anna Katharina
Graskamp, Emily Hayes, Erkki Huhtamo, Martyn Jolly, Joe Kember,
Frank Kessler, Machiko Kusahara, Sabine Lenk, Vanessa Otero, Carmen
López San Segundo, Ariadna Lorenzo Sunyer, Daniel Pitarch, Jordi
Pons, Montse Puigdeval, Angélique Quillay, Angel Quintana Morraja,
Nadezhda Stanulevich, Jennifer Tucker, Kurt Vanhoutte, Márcia
Vilarigues, Joseph Wachelder, Artemis Willis, Lee Wing Ki, Irene
Suk Mei Wong, and Nele Wynants.
eBook
Optimal design of electromagnetic interference of LED lamp switching power supply based on TRIZ theory
The innovation method TRIZ is an innovative methodology that can analyze problems and solve them and has been widely used in many fields. In this paper, TRIZ theory is applied to optimize the design of the electromagnetic interference (EMI) problem of a model of LED lamps and lanterns switching power supply. The tools of resource analysis, component analysis, functional analysis, and cause-effect analysis are used to analyze the problem of excessive EMI encountered in the design of LED lamps and lanterns, and the tools of technical contradiction and material field analysis are used to improve the problem of reducing EMI. Two solutions are obtained to improve the problem of high EMI by changing the Power inductor design method of the input voltage and by adding capacitors to form a Π-type filter circuit.
Journal Article