Three research questions
The laboratory’s observational program is organized around three questions, from how planetary systems form to whether temperate rocky planets can be characterized directly. Each card summarizes the measurement approaches and links to the instruments involved; the observed systems behind these results are mapped below.
Swipe to compare the three research questions.
How do planetary systems form?
Occurrence statistics, resolved disk structure, and atmospheric abundances each preserve a record of where and how planets assemble.
Demographics, disk structure, and atmospheric chemistry provide complementary formation constraints; PDS 70 hosts two directly imaged protoplanets.
What are exoplanet atmospheres like — and how do they change?
High-resolution spectra resolve individual molecular lines: their pattern gives composition, their width rotation, their shift orbits — and their variation in time maps storms as the object spins.
Line pattern, width, and shift give composition, rotation, and orbit; their time variation maps the atmosphere as the object rotates.
Can we directly characterize temperate rocky planets?
Reaching 10−10 contrast at small separations is a technology problem: testbed-validated coronagraphy and fiber & photonic nulling, aimed at nearby solar-system analogs and, with HWO, at Earth analogs.
Indicative contrast regimes; performance depends on wavelength, angular separation, aperture, stability, calibration, and post-processing.
Observed systems and survey samples
42 lab-associated systems, three survey samples (43 NIRC2-vortex disk targets, 30 Keck/VLT debris-disk stars, 155 young M dwarfs), and a reference layer of 37 imaged planets and benchmark companions — a quick-look tool for ADS and SIMBAD searches. Returned publications extend beyond this laboratory’s; for exhaustive confirmed-planet samples, see the NASA Exoplanet Archive ↗. Filter by category, select a featured system, or browse the complete index below.
Browse selected systems · ADS literature & SIMBAD
Imaged / resolved· 22
Spectra / HDC· 7
Disks / formation· 10
Deep limits· 3
Reference targets· 37
Survey programs · lab co-authored· 6
Instruments, testbeds & programs
Six featured; filter or expand for all fourteen.
Swipe featured projects, or expand the catalog.
ET LAB / CALTECHHISPEC
IN BUILD · FIRST LIGHT 2027Fiber-fed near-infrared Keck spectrograph with R ≈ 100,000 across yJHK — KPIC’s facility-class successor for high-dispersion companion spectroscopy.
SCALES TEAMSCALES
IN BUILD · KECKKeck’s thermal-infrared imager and integral-field spectrograph (PI Andy Skemer, UCSC), vortex coronagraphy in K, L, and M; follow-up of Gaia astrometric-acceleration companions.
ET LAB / CALTECHHCST
TESTBED · SPACE CORONAGRAPHYCoronagraph masks, a kilo-actuator deformable mirror, low-order sensing, and focal-plane control validate segmented-aperture methods approaching 10−10; infrared benches qualify coronagraphs, dispersion correctors, fibers, and modules.
TMT INTERNATIONAL OBSERVATORYMODHIS
DESIGN · TMT FIRST LIGHTA TMT first-light, fiber-fed high-resolution spectrograph: atmospheric spectroscopy of planets around nearby stars, including rocky M-dwarf planets; related concepts for ELT/ANDES.
NASAHWO coronagraph contributions
CONCEPT · SPACECoronagraph architectures, wavefront sensing and control, and laboratory validation for the Habitable Worlds Observatory — NASA’s concept for imaging and characterizing potentially habitable exoplanets. A concluded NASA SAT with JPL set the record broadband dark-hole contrast in vacuum; a new 2025 SAT demonstrates the apodized vortex coronagraph.
ET LAB / CALTECHFiber nulling testbed
TESTBED · DEMONSTRATED WITH KPICPolychromatic testbed for vortex-fiber and mode-selective nulling: a vortex mask and single-mode fiber reject on-axis starlight, retaining companion light below λ/D — demonstrated on sky with KPIC.
ET LAB / CALTECH · JPLAstrophotonics
TESTBED · WITH COOIntegrated photonics for spectroscopy and interferometry — compact spectrographs, achromatic nulling tricouplers, mode-selective lanterns, the Photonic Lantern Nuller. Nem Jovanovic (COO) leads; ET Lab hosts researchers and experiments.
DESAI ET AL. / JPLVortex mask technologies
TESTBED · VECTOR + SCALARVector (liquid-crystal) and scalar vortex focal-plane masks — wrapped-staircase, phase-dimple, and metasurface designs — developed with Eugene Serabyn, Jorge Llop-Sayson, Niyati Desai, and Lorenzo König.
W. M. KECK OBSERVATORYNIRC2 vortex coronagraph
ON SKY · KECK IIVector vortex masks in L and M within Keck/NIRC2, supporting community observations of planets and disks — PDS 70, MWC 758, the AF Lep b discovery (Franson et al. 2023).
NASA / CHRIS GUNNJWST programs
ON SKY · SPACEMIRI observations of the α Centauri A candidate, deep imaging of ε Eridani and ε Indi, and spectroscopy of directly imaged giants.
ET LAB / CALTECHWIRC+POL
ON SKY · PALOMARNear-infrared spectropolarimeter at the Hale 200-inch: polarization and rotational variability constrain brown-dwarf clouds and structure, and probe asymmetries in explosive transients.
ET LAB / CALTECHPARVI
LEGACY · PALOMARSingle-mode-fiber precision-radial-velocity demonstrator behind PALM-3000 at the Hale 200-inch.
A. GHIZZI PANIZZA / ESO · CC BY 4.0NEAR
LEGACY · VLT · 20192019 VLT/VISIR mid-infrared vortex campaign targeting α Centauri’s habitable zones.
ET LAB / CALTECHKPIC
DECOMMISSIONED · 2025KPIC demonstrated high-dispersion coronagraphy, coupling Keck II adaptive optics to NIRSPEC through single-mode fibers and characterizing ~30 companions. Decommissioned December 2025.
Decommissioned instruments’ publications and pipelines stay online.
From current observatories to ELTs and HWO
Two lines: vortex coronagraphy — Palomar and Keck to METIS and HWO; fiber-fed high-resolution spectroscopy — KPIC to HISPEC, MODHIS, and ELT concepts.
Vortex coronagraphy on sky
- 2005
- phase-mask concept introduced
- 2010
- first vortex images of exoplanets — three HR 8799 planets at Palomar
- 8
- instruments — seven on sky, Keck's SCALES in construction
- 2022
- Vacuum demonstrations near 10−9 in 10% bandwidth — 1.6×10−9 on an unobscured aperture (Ruane et al. 2022) and 4.7×10−9 on a segmented one (Riggs et al. 2022), Decadal Survey Testbed
- 2023
- AF Lep b discovered (Franson et al. 2023) — lowest-mass imaged exoplanet with a dynamical mass
- 2024
- Apodized vortex selected as pipe-cleaner for HWO coronagraph integrated modeling
- 350+
- vortex-coronagraph publications (NASA ADS)
High-resolution exoplanet spectroscopy
- ~30
- exoplanets and brown dwarfs characterized at R ≈ 35,000
- spins
- first science: spins of HR 8799 d and e
- C/O
- metallicity, C/O, and isotopologues constrain each companion’s formation — uniform retrievals of eight (Xuan et al. 2024)
- moons
- exomoon searches via radial-velocity monitoring of imaged companions (Ruffio, Horstman, et al. 2023)
- 2024
- Gliese 229 B resolved as a 12-day binary — VLT CRIRES+/GRAVITY (Jerry Xuan, PhD '25), and independently Keck/NIRSPEC RVs (Sam Whitebook)
- 2026
- Record broadband starlight suppression for exoplanet spectroscopy — 4×10−10 over 20% bandwidth; 2×10−9 at 25% and 4×10−9 at 30% through a single-mode fiber; 5×10−9 at 30% in a small dark hole — all in vacuum (NASA SAT, with JPL)
- 55+
- publications in the KPIC science library · legacy page
Next-generation instruments
- HISPEC
- KPIC's fiber architecture as a Keck facility instrument — R ≈ 100,000 across yJHK, first light 2027
- SCALES
- vortex imaging and medium-resolution integral-field spectroscopy at Keck (PI Andy Skemer, UCSC) with ET Lab vortex contributions; related coronagraphy for ELT/METIS and nearby systems
- MODHIS
- fiber-fed high-resolution spectrograph design for TMT; related planet channel under study for ELT/ANDES
- HWO
- 10−10 contrast in space — apodized-vortex architectures for segmented apertures — Habitable Worlds Observatory
Team
The team spans Caltech Astronomy and Physics, Caltech Optical Observatories, JPL, and affiliated programs; students and postdocs lead instrument development, observing, analysis, and publications.
JPL SENIOR RESEARCH SCIENTIST · DIRECTOR OF INSTRUMENTATION, CALTECH OPTICAL OBSERVATORIES
Develops vortex coronagraphy, high-dispersion coronagraphy, and facility instruments for direct imaging and spectroscopy of exoplanets. FULL PROFILE →
Graduate students
Postdoctoral researchers
Affiliated scientists, engineers & visitors
JPLNiyati Desai · Sam Halverson · Lorenzo König · Jorge Llop-Sayson · Camilo Mejia Prada · Bertrand Mennesson · Susan Redmond · AJ Riggs · Garreth Ruane · Eugene Serabyn · Gautam Vasisht · James K. Wallace
IPAC / NEXSCICharles Beichman · David Ciardi · Tiffany Meshkat
AEROSPACEStephanie Leifer
Undergraduate researchers
The current Summer Undergraduate Research Fellowship cohort, in residence at the lab. Past undergraduate researchers are listed in the archive below.
Full profiles and contact details are listed in the Caltech PMA directory ↗.
Alumni
Postdoctoral alumni · 20
Graduate alumni · 12
Undergraduate research alumni · 53
Undergraduate research alumni · 2015–2025
News
Three selected results; the full record follows.
The concluded NASA SAT with JPL reached 4×10−10 raw contrast over 20% bandwidth in vacuum — the deepest, widest-bandwidth dark hole demonstrated to date.
FIG: MAWET, LLOP-SAYSON, RUANE & RIGGS / NASA EXEP
Sam Whitebook and collaborators identified an ultracompact brown-dwarf binary undergoing mass transfer.
ART: CALTECH / R. HURT (IPAC)
JWST spectra analyzed by Jean-Baptiste Ruffio and Jerry Xuan provide constraints on the formation pathway of massive giant planets.
ART: JEAN-BAPTISTE RUFFIO