SearcharxivSearch

arXiv subjects

Annie Tan

Publications and source records attributed to Annie Tan.

4 recordsLinked to original sources

A waveguide spectrometer for high-resolution millimeter-wave imaging

We present the design and development of a novel, compact integrated on-chip spectrometer operating at millimeter (mm) and submillimeter (sub-mm) wavelengths. The Superconducting Waveguide Integrated Submillimeter Spectrometer (SWISS) promises significant improvements in spectral resolution, optical efficiency, and frequency coverage over current mm-wave spectrometers by using a free-space rectangular waveguide architecture. Light is coupled in through the antenna front end, which separates the two polarizations and passes them to the waveguide spectrometer through a contactless metamaterial transition. Each waveguide spectrometer consists of a feedline coupled to a series of filters based on single-pole cavity resonators with varying resonant frequencies. To maximize packing density, the filter banks are oriented out of the focal plane, and an E-plane bend in the output from the cavity filters enables a planar and scalable construction. The output of each filter is coupled to a kinetic inductance detector (KID) to enable high multiplexing factors. The spectrometer is fabricated using stacks of silicon wafers etched with a deep reactive-ion etch (DRIE) and metallized. In these proceedings, we discuss current development on a SWISS prototype including measurements on a prototype antenna front end contactless transition and fabrication a prototype waveguide spectrometer.

astro-ph.IM

SuMAC: On-sky demonstration of multi-pixel on-chip millimeter-wave spectroscopy at the Large Millimeter Telescope

The SuperSpec-MUSCAT Collaboration (SuMAC) is an effort to operate SuperSpec spectrometers in the MUSCAT instrument at the Large Millimeter Telescope (LMT). SuperSpec is an on-chip filterbank spectrometer using kinetic inductance detectors (KIDs), with moderate $R\sim 200$ spectral resolution for observing in the 1 mm atmospheric window (190-300 GHz). While nominally a continuum camera operating a 1.1 mm, MUSCAT was also designed to operate as a testbed for pioneering detection technologies. In July 2025, three SuperSpec devices were installed and commissioned in the MUSCAT cryostat with minimal modifications to the system. This work presents an overview of SuperSpec's deployment and performance in MUSCAT along with the main results from the Summer 2025 observation campaign. Highlights include the detection of CO emission line in the galaxy NGC253, mapping the Orion KL region, and preliminary line intensity mapping scans.

astro-ph.IM

Full quantitative near-field characterization of strongly coupled exciton-plasmon polaritons in thin-layered WSe2 on a monocrystalline gold platelet

Exciton-plasmon polaritons (EPPs) are attractive both for the exploration of fundamental phenomena and applications in nanophotonics. Previous studies of EPPs mainly relied on far-field characterization. Here, using near-field optical microscopy, we quantitatively characterize the dispersion of EPPs existing in 13-nm-thick tungsten diselenide (WSe$_2$) deposited on a monocrystalline gold platelet. We extract from our experimental data a Rabi splitting of 81 meV, and an experimental effective polariton loss of 55 meV, demonstrating that our system is in the strong-coupling regime. Furthermore, we measure for the first time at visible wavelengths the propagation length of these EPPs for each excitation energy of the dispersion relation. To demonstrate the quantitative nature of our near-field method to obtain the full complex-valued wavevector of EPPs, we use our near-field measurements to predict, via the transfer matrix method, the far-field reflectivities across the exciton resonance. These predictions are in excellent agreement with our experimental far-field measurements. Our findings open the door towards the full near-field study of light-manipulating devices at the nanoscale.

physics.optics

Who and what gets recognized in peer recognition

Previous work has identified that recognition from others is an important predictor of students' participation, persistence, and career intentions in physics. However, research has also found a gender bias in peer recognition in which student nominations of strong peers in their physics course disproportionately favor men over women. In this study, we draw on methods from social network analysis and find a consistent gender bias in which men disproportionately under-nominate women as strong in their physics course in two offerings of both a lecture course (for science and engineering, but not physics, majors) and a distinct lab course (for science, engineering, and physics majors). We also find in one offering of the lecture course that women disproportionately under-nominate men, contrary to what previous research would predict. We expand on prior work by also probing two data sources related to who and what gets recognized in peer recognition: students' interactions with their peers (who gets recognized) and students' written explanations of their nominations of strong peers (what gets recognized). Results suggest that the nature of the observed gender bias in peer recognition varies between the instructional contexts of lecture and lab. In the lecture course, the gender bias is related to who gets recognized: both men and women disproportionately over-nominate their interaction ties to students of their same gender as strong in the course. In the lab course, the gender bias is also related to what gets recognized: men nominate men more than women because of skills related to interactions, such as being helpful. These findings illuminate the different ways in which students form perceptions of their peers and add nuance to our understanding of the nature of gender bias in peer recognition.

physics.ed-ph