Publications by authors named "Nazim A Bharmal"
The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. To achieve this, the pupil-modulated point-diffraction interferometer (m-PDI) was presented in an earlier paper.
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- The study presents initial results from a four-telescope integrated optics discrete beam combiner (DBC) tested at the William Herschel Telescope, designed to improve astronomical observations.
- The DBC, created using ultrafast laser inscription on a single substrate, processes light from stars like Vega and Altair at the H-band (1.6 µm) while utilizing a deformable mirror for efficient light injection.
- The results indicated that the measured visibility amplitudes and closure phases were affected by a significant dispersion from expected values, primarily due to a low signal-to-noise ratio, marking an initial step toward validating DBC for long-baseline interferometry.
The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. In order to achieve this, a high-sensitivity wavefront sensor, the pupil-modulated point-diffraction interferometer (m-PDI), is presented.
View Article and Find Full Text PDFIt is shown how the solenoidal component of noise from the measurements of a wavefront slope sensor can be utilized to estimate the total noise: specifically, the ensemble noise variance. It is well known that solenoidal noise is orthogonal to the reconstruction of the wavefront under conditions of low scintillation (absence of wavefront vortices). Therefore, it can be retrieved even with a nonzero slope signal present.
View Article and Find Full Text PDFA deformable mirror (DM) is a mirror whose surface can be deformed in order to correct for optical aberrations. If a DM is used in a feed-forward operation (i.e.
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