Enabling Quantitative Polarimetry for Keck/NIRC2: Preliminary Mueller Matrix Model Calibration

@misc{zhang2026enabling,
  title = {{Enabling Quantitative Polarimetry for Keck/NIRC2: Preliminary Mueller Matrix Model Calibration}},
  author = {Manxuan Zhang and Briley L. Lewis and Maxwell A. Millar-Blanchaer and Eduardo Marin and Jayke S. Nguyen and William Melby and Carlos Alvarez and Jaren N. Ashcraft and Mahawa Cisse and Charles-Antoine Claveau and Jacques-Robert Delorme and Greg Doppmann and Michael P. Fitzgerald and Matthew Freeman and Percy Gomez and Trisha Hammen and Ryan Hersey and Nemanja Jovanovic and Marc Kassis and Scott Lilley and Jessica Lu and James E. Lyke and Keith Matthews and Dimitri Mawet and Thomas McIntosh and Max Service and Lauren Simmons and Jacob Taylor and Rob G. van Holstein and Ed Wetherell},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2608.14873},
  eprint = {2608.14873},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.14873},
  note = {CC BY-NC-SA 4.0},
}

TY  - UNPB
TI  - Enabling Quantitative Polarimetry for Keck/NIRC2: Preliminary Mueller Matrix Model Calibration
AU  - Manxuan Zhang
AU  - Briley L. Lewis
AU  - Maxwell A. Millar-Blanchaer
AU  - Eduardo Marin
AU  - Jayke S. Nguyen
AU  - William Melby
AU  - Carlos Alvarez
AU  - Jaren N. Ashcraft
AU  - Mahawa Cisse
AU  - Charles-Antoine Claveau
AU  - Jacques-Robert Delorme
AU  - Greg Doppmann
AU  - Michael P. Fitzgerald
AU  - Matthew Freeman
AU  - Percy Gomez
AU  - Trisha Hammen
AU  - Ryan Hersey
AU  - Nemanja Jovanovic
AU  - Marc Kassis
AU  - Scott Lilley
AU  - Jessica Lu
AU  - James E. Lyke
AU  - Keith Matthews
AU  - Dimitri Mawet
AU  - Thomas McIntosh
AU  - Max Service
AU  - Lauren Simmons
AU  - Jacob Taylor
AU  - Rob G. van Holstein
AU  - Ed Wetherell
PY  - 2026
DA  - 2026/08/14
PB  - arXiv
DO  - 10.48550/arxiv.2608.14873
UR  - https://arxiv.org/abs/2608.14873
AB  - The Keck/NIRC2 infrared imager was upgraded in 2025 with dual-beam polarimetric observing modes spanning approximately 1.1--4.1 microns (JHKL' bands). We present a preliminary JHK calibration of NIRC2 Polarimetry using a wavelength-dependent Mueller matrix model of the Keck tertiary mirror (M3), half-wave plate (HWP), image rotator (IMR), downstream optics, and Wollaston prism. We constrain the model downstream of M3 using dome flat sequences spanning ten HWP and nine IMR angles in each band. Although the model reproduces the dominant modulation, the residuals show structure dependent on HWP and IMR angle. Measurement matrix inversion of unpolarized standard star observations gives M3 diattenuations of 0.0119+/-0.0009, 0.0098+/-0.0004, and 0.0068+/-0.0005 in J, H, and Kp, substantially closer to Fresnel predictions for aluminum than the values derived from dome flats. The larger dome flat modulation may indicate polarization in the incident dome illumination or Mueller matrix model inaccuracies. These results establish an initial calibration framework while motivating improved input polarization constraints, fixed HWP parameters from previous laboratory measurements, model validation with polarized standard stars, and extension to L'.
ER  -