Near-infrared wavefront sensing

Wizinowich, Peter; Chun, Mark; Mawet, Dimitri; Agapito, Guido; Dekany, Richard; Esposito, Simone; Fusco, Thierry; Guyon, Olivier; Hall, Donald N. B.; Plantet, Cédric; Rigaut, François

doi:10.1117/12.2233035

Cited by 14 publications

(15 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, for consistency with the error budget used in a previous study, 3 we add a constant error of 165 nm rms to the residual in NGS mode, representing miscellaneous errors from undetermined sources.…”

Section: Simulations Parametersmentioning

confidence: 99%

See 1 more Smart Citation

End-to-end simulations of a near-infrared pyramid sensor on Keck II

Plantet¹,

Agapito²,

Giordano³

et al. 2017

Proceedings of the Adaptive Optics for Extremely Large Telescopes 5

Self Cite

View full text Add to dashboard Cite

The future upgrade of Keck II telescopes adaptive optics system will include a pyramid wavefront sensor working in the near-infrared (J and H band). It will benefit from the recently developed avalanche photodiode arrays, specifically the SAPHIRA (Selex) array, which provides a low noise ( 1 e-at high frame rates). The system will either work with a natural guide star (NGS) in a single conjugated adaptive optics system, or in a laser guide star (LGS) mode. In this case, the pyramid would be used as a low-order sensor only. We report on a study of the pyramid sensor's performance via end-to-end simulations, applied to Keck's specific case. We present the expected Strehl ratio with optimized configurations in NGS mode, and the expected residual on low orders in LGS mode. In the latter case, we also compare the pyramid to LIFT, a focal-plane sensor, demonstrating the ability of LIFT to provide a gain of about 2 magnitudes for low-order sensing.

show abstract

Section: Simulations Parametersmentioning

confidence: 99%

“…3 The main goal of this upgrade is to perform direct imaging and slit spectroscopy of exoplanets around M dwarfs. The flux from these stars is very faint at optical wavelengths, but sufficient in the near-infrared to use as NGSs in a single conjugated AO system, given the adequate detector technology.…”

Section: Introductionmentioning

confidence: 99%

End-to-end simulations of a near-infrared pyramid sensor on Keck II

Plantet¹,

Agapito²,

Giordano³

et al. 2017

Proceedings of the Adaptive Optics for Extremely Large Telescopes 5

Self Cite

View full text Add to dashboard Cite

show abstract

“…The next step being undertaken as part of a phased approach to implementing the Keck Planet Imager and Characterizer (KPIC; Mawet, [24]) will be to integrate a single mode fiber injection unit on the Keck II AO bench to feed the NIRSPEC science instrument; the fiber injection unit includes a pupil plane where apodizers can be installed (Ruane et al, [25]). A proposal for a near-infrared pyramid wavefront sensor has been submitted that would support NGS AO science observations with both NIRC2 and the fiber injection unit (Wizinowich,[26]). A proposal for a coronagraph module has also been submitted which would include a MEMS deformable mirror in a pupil plane and a focal plane coronagraph mask, which would be installed just before the fiber injection unit.…”

Section: Adaptive Optics Upgrades and Activitiesmentioning

confidence: 99%

Keck II laser guide star AO system and performance with the TOPTICA/MPBC laser

et al. 2016

Self Cite

View full text Add to dashboard Cite

The Keck II Laser Guide Star (LGS) Adaptive Optics (AO) System was upgraded from a dye laser to a TOPTICA/MPBC Raman-Fibre Amplification (RFA) laser in December 2015. The W. M. Keck Observatory (WMKO) has been operating its AO system with a LGS for science since 2004 using a first generation 15 W dye laser. Using the latest diode pump laser technology, Raman amplification, and a well-tuned second harmonic generator (SHG), this Next Generation Laser (NGL) is able to produce a highly stable 589 nm laser beam with the required power, wavelength and mode quality. The beam's linear polarization and continuous wave format along with optical back pumping are designed to improve the sodium atom coupling efficiency over previously operated sodium-wavelength lasers. The efficiency and operability of the new laser has also been improved by reducing its required input power and cooling, size, and the manpower to operate and maintain it.The new laser has been implemented on the telescope's elevation ring with its electronics installed on a new Nasmyth sub-platform, with the capacity to support up to three laser systems for future upgrades. The laser is projected from behind the telescope's secondary mirror using the recently implemented center launch system (CLS) to reduce LGS spot size. We will present the new laser system and its performance with respect to power, stability, wavelength, spot size, optical repumping, polarization, efficiency, and its return with respect to pointing alignment to the magnetic field. Preliminary LGSAO performance is presented with the system returning to science operations. We will also provide an update on current and future upgrades at the WMKO.

show abstract

“…In practice, these modes are determined through techniques involving centroid tracking used regularly in adaptive optics applications [46,47].…”

Section: Modal Representation Of Aero-optical Wavefrontsmentioning

confidence: 99%

Predictive dynamic digital holography

2016

View full text Add to dashboard Cite

Digital holography has received recent attention for many imaging and sensing applications, including imaging through turbulent and turbid media, adaptive optics, three-dimensional projective display technology and optical tweezing. It holds several advantages over classical methods for wavefront sensing and adaptive-optics correction, chief among these being significantly fewer and simpler optical components. A significant obstacle for digital holography in real-time applications, such as wavefront sensing for high-energy laser systems and high-speed imaging for target tracking, is the fact that digital holography is computationally intensive; it requires iterative virtual wavefront propagation and hill-climbing algorithms to optimize sharpness criteria. This research demonstrates real-time methods for digital holography based on approaches for optimal and adaptive identification, prediction, and control of optical wavefronts. The methods presented integrate minimum-variance wavefront prediction into dynamic digital holography schemes to accelerate the wavefront correction and image sharpening algorithms. Further gains in computational efficiency are demonstrated in this work with a variant of localized sharpening in conjunction with predictive dynamic digital holography for real-time applications. This "subspace correction" method optimizes sharpness of local regions in a detector plane by parallel independent wavefront correction on reduced-dimension subspaces of the complex field in a spectral plane.ii The dissertation of Sennan David Sulaiman is approved.

show abstract

Near-infrared wavefront sensing

Cited by 14 publications

References 16 publications

End-to-end simulations of a near-infrared pyramid sensor on Keck II

End-to-end simulations of a near-infrared pyramid sensor on Keck II

Keck II laser guide star AO system and performance with the TOPTICA/MPBC laser

Predictive dynamic digital holography

Contact Info

Product

Resources

About