The Vector APP Coronagraph - realizing new coronagraph designs ...

Vector APP Coronagraph realizing new coronagraph designs

with polarization techniques

Gilles Otten Frans Snik, Matthew Kenworthy, Christoph Keller

Leiden Observatory, Netherlands

Matthew Miskiewicz, Michael Escuti North Carolina State University, USA

Johanan Codona University of Arizona, USA

Apodizing Phase Plate (APP)

Codona et al. 2004, 2006, Kenworthy et al. 2007

Apodizing Phase Plate (APP)

VLT/NACO L-band realtime (pre 2011 drifting)

Pros and Cons of APP

Single Optic Easy alignment

Insensitive to tip-tilt variations

One-sided PSF* Chromatic

*depends on phase pattern

Vector-APP

Patterned liquid crystal encodes phase using vector-phase Half-wave plate flips handedness

Concept described in Snik et al. (Proc. SPIE 8450, 2012)

Prototype characterized in Otten et al. (Optics Express subm., 2014)

Breakthrough manufacturing techniques Direct write Miskiewicz & Escuti, OpEx, Vol. 22, Issue 10, pp. 12691-12706 (2014)

Achromatization Komanduri, Lawler & Escuti, OpEx, Vol. 21, Issue 1, pp. 404-420 (2013)

Vector-APP

Current prototype 500 – 900 nm 25 micron pixel size, 5.5 mm diameter

between crossed polarizers

750 nm

Laboratory data

Achromatic behaviour

characterization of plate Input Lab

retardance

Vector-APP

Two extra optical components only for splitting??

Simplifying the vAPP

Smearing due to wavelength-dependent splitting but only one optic

Going on-sky at LBT

4 micron vAPP currently in LBT/LMIRCam with support from Phil Hinz, Manny Montoya, University of Arizona, USA

Described in Snik et al. (Proc. SPIE 9147, 2014)

Polarimetry with vAPP

Snik et al., 2014

Snik et al., 2014

Phase patterns

Phase part of complex coronagraph Carlotti et al. 2013

1e-5 contrast ~2-6 λ/D phase-only Christoph Keller

360 degree phase patterns Contrast: 1e-5 ~2-8 λ/D 19% Strehl

Contrast: 1e-8 ~6-10 λ/D 53% Strehl

John Codona Christoph Keller

360 degree phase pattern

Simulated PSF John Codona

Lab measurement using spatial light modulator

Poor man's PIAA Guyon, 2003 Image credit: Martinache Replace aspheric optics by patterned vector phase elements Only works for one handedness of polarization but is order of

magnitude cheaper Only works narrowband

Aspheric pupil remapping optics

It is possible to build almost any phase pattern up to 100% bandwidth

What would you do with this power?