Sumários
Wavefront metrology (class 1 in 3)
10 Abril 2024, 15:00 • Alexandre Pereira Cabral
A Shack-Hartmann wavefront sensor was built based on an array of lenses that divide / sample the incoming wavefront into small sub-apertures, focusing independently the light from each lens in a 2D sensor that captures the focal plane pattern. This pattern was processed in order to obtain the position of each focus point from each individual lens.
An incident plane wave was created using a spatial filter and a collimated lens to produce a grid of equidistant focal points, the reference position, while several distorted waves (corresponding to a point source from an optical fibre in controlled positions) result in an uneven distribution of points that were referenced to the ideal plan wave situation in order to determine with the sensor the position of the fibre tip, using the Shack-Hartman sensor to measure an unknown wavefront based of the focus shifts from the calibration.
JWST cophasing elements
8 Abril 2024, 14:00 • José Manuel Rebordão
Hardware elements for cophasing. Managing object and
pupil imaging
Phase retrieval techniques: IFTA/GW and phase
diversity – an overview
NEXT
JWST: NIRSPec detectors, NIRISS
5 Abril 2024, 09:00 • José Manuel Rebordão
NIRSpec detectors – overview and explanation of key
specification and technological concepts (by Prof. Manuel Abreu)
NIRISS – system overview; grisms, aperture masking
Interferometry mode. PSF’s. Examples.
NEXT
Spectroscopy (class 2 in 2)
27 Março 2024, 15:00 • Alexandre Pereira Cabral
Analysis and operation of spectrometers and monochromators to have an introductory approach to spectral decomposition of polychromatic light.
Study of the dispersion of light, the properties of diffracting elements and how they are used in monochromators and spectrographs, and the concepts of spectral resolution and resolving power.
Characterization of non-monochromatic light.
JWST: NIRSPec detectors, NIRISS
25 Março 2024, 14:00 • José Manuel Rebordão
NIRSpec detectors – overview and explanation of key
specification and technological concepts (by Prof. Manuel Abreu)
NIRISS – system overview; grisms, aperture masking Interferometry
mode. PSF’s. Examples.
NEXT