Sumários

JWST: FGS

17 Março 2025, 14:00 • José Manuel Rebordão

Specific topics: TMA architecture, orbits, Strehl ratio. The FSM and the real image of the PM. Sequence of real images of the PM throughout JWST instruments. EM meaning of conjugation between planes.
FGS and its heritage. Redundancy. SEU concept. Engineering subsystems and criticality.
FGS architecture and its operational modes.
 
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NIRCam

James Webb Space Telescope

14 Março 2025, 09:00 • José Manuel Rebordão

JWST – James Webb Space Telescope
Mission. Platform: Space systems specificities. Architecture. Main systems. Orbit. OTE and ISIM. FoR, FoV, iFoV. TMA architecture. OTE optics.
 
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Pupil function and PSF. Wavefront errors, individual surface contribution.
FGS, NIRCam, MIRI. NIRSpec

Holography (class 2 of 3)

12 Março 2025, 15:00 • Alexandre Pereira Cabral

Introduction to practical Holography, building objects.

Setup of a Denisyuk configuration, consisting of a volume-reflection holography technique. As a recording medium, a silver halide emulsion on a glass plate will be used (a matrix of cohesive silver crystals in a transparent medium). During exposure, the reference wave and the waves reflected from the object result in an interference structure that was recorded within the emulsion.

Students produced their own objects that will be exposed in a 50 mm x 50 mm plate.

Students performed several exposures using different types of objects (including lenses or mirrors to generate holographic optical elements known as HOE.

Analysis of non-holographic technics, bases on the Peper’s ghost concept, will be shown in the lab for analysis.

Nonlinear optics

10 Março 2025, 14:00 • José Manuel Rebordão

Third order effects: spectral broadening, supercontinuum; four wave mixing, holography, phase-conjugated mirrors.
Overview: parametric and non-parametric effects, virtual states.
Photo-refractive materials - basics
 
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JWST – system consideration. Subsystems
TRL, SRL.

Nonlinear optics

7 Março 2025, 09:00 • José Manuel Rebordão

2nd order nonlinear effects, OFC, OPA, OPO, SPDC.
Types of phase matching. A very reference to coupled-waves theory and of its typical outcomes.
Brief overview of the importance of SPDC to optical qubits.
Third order effects: optical Kerr effect, self-phase modulation (SPM), self-focusing, filamentation.
 
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Raman gain, 4 wave mixing, conjugated phase mirrors, photo-refractive materials.
Third order effects: spectral broadening, supercontinuum; four wave mixing, holography, phase-conjugated mirrors.
Overview: parametric and non-parametric effects, virtual states.
BIBLIOGRAPHY
Saleh