Author: SABINO CHAVEZ CERDA

Segmented vortex telescope and its tolerance to diffraction effects and primary aberrations

JUAN PABLO TREVIÑO GUTIERREZ Omar López Cruz SABINO CHAVEZ CERDA (2013)

The segmented large millimeter telescope (LMT/GTM) is the largest spatial light modulator capable of producing vortex beams of integer topological charge. This observing mode could be applied for direct exoplanet searches in the millimeter or submillimeter regimes. The stability of the vortex structure against aberrations and diffraction effects inherent to the size and segmented nature of the collector mirror was studied. In the presence of low-order aberrations, the focal distribution of the system remains stable. Results show that these effects depend on the topological charge of the vortex and the relative orientation of the aberration with respect to the antenna axis. Coma and defocus show no large effects in the image at the focal plane; however, the system is very sensitive to astigmatism. Heat turbulence, simulated by random aberrations, shows that the system behaves in a similar way as astigmatism dissociating the vortices. The segmented vortex telescope is proposed as a novel approach for the detection of giant planets outside circumstellar disks around nearby stars. Since results are applicable to other facilities with segmented surfaces, it is suggested that this idea should be considered as a regular observation mode complementary to interferometric methods.

Article

Aberrations Astronomy Diffraction Millimeter waves Phase modulators Planets Spatial light modulators Telescopes CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA

Discrete-like diffraction dynamics in free space

FRANCISCO SOTO EGUIBAR SABINO CHAVEZ CERDA Héctor Manuel Moya Cessa (2013)

We introduce a new class of paraxial optical beams exhibiting discrete-like diffraction patterns reminiscent to those observed in periodic evanescently coupled waveguide lattices. It is demonstrated that such paraxial beams are analytically described in terms of generalized Bessel functions. Such effects are elucidated via pertinent examples.

Article

Diffraction Dispersion Propagation CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA