Dr. Alejandro V. Maldonado Profile

Dr. Alejandro V. Maldonado

Area of Expertise:

Metrology , Fabrication , Computational Analysis , Design , Systems

I am a little different than most PhD's in optics. I have a broad understanding of optics with my optical systems engineering education. Some of the areas I am particularly adept to include: design (optical design software, and 3D CAD modeling w/ FEA familiarity), fabrication, metrology, mechanics, and computational analysis. I also understand that it takes everything you've got to be a great team member at Google, and I think I am prepared to give it my all.

Proceedings Article | 28 July 2014 Paper

Measuring large mirrors using SCOTS: the Software Configurable Optical Test System

J. Burge, P. Su, G. Butel, R. Huang, A. Maldonado, T. Su

Proceedings Volume 9151, 91510Z (2014) https://doi.org/10.1117/12.2057726

KEYWORDS: Mirrors, Cameras, Optical testing, Interferometry, Imaging systems, Deflectometry, Aspheric lenses, Modulation, Calibration, Light

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Proceedings Article | 19 December 2013 Paper

Study of the instrument transfer function of a free-form optics metrology system: SCOTS

Tianquan Su, Alejandro Maldonado, Peng Su, Ping Zhou, James Burge

Proceedings Volume 9046, 904602 (2013) https://doi.org/10.1117/12.2037040

KEYWORDS: Mirrors, Cameras, Imaging systems, Point spread functions, Modulation transfer functions, Deflectometry, Spatial frequencies, Metrology, Interferometry, X-rays

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SPIE Journal Paper | 2 December 2013

Aspheric and freeform surfaces metrology with software configurable optical test system: a computerized reverse Hartmann test

Peng Su, Manal Khreishi, Tianquan Su, Run Huang, Margaret Dominguez, Alejandro Maldonado, Guillaume Butel, Yuhao Wang, Robert Parks, James Burge

OE, Vol. 53, Issue 03, 031305, (December 2013) https://doi.org/10.1117/12.10.1117/1.OE.53.3.031305

KEYWORDS: Cameras, Mirrors, Calibration, Aspheric lenses, Optical testing, Interferometry, Freeform optics, Metrology, Deflectometry, Imaging systems

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Proceedings Article | 31 August 2010 Paper

Multiwalled carbon nanotubes for stray light suppression in space flight instruments

John Hagopian, Stephanie Getty, Manuel Quijada, June Tveekrem, Ron Shiri, Patrick Roman, James Butler, Georgi Georgiev, Jeff Livas, Cleophus Hunt, Alejandro Maldonado, Saikat Talapatra, Xianfeng Zhang, Stergios Papadakis, Andrew Monica, David Deglau

Proceedings Volume 7761, 77610F (2010) https://doi.org/10.1117/12.864386

KEYWORDS: Stray light, Mirrors, Reflectivity, Carbon nanotubes, Silicon, Bidirectional reflectance transmission function, Aerospace engineering, Nanoimprint lithography, Stray light control, Light scattering

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Observations of the Earth are extremely challenging; its large angular extent floods scientific instruments with high flux within and adjacent to the desired field of view. This bright light diffracts from instrument structures, rattles around and invariably contaminates measurements. Astrophysical observations also are impacted by stray light that obscures very dim objects and degrades signal to noise in spectroscopic measurements. Stray light is controlled by utilizing low reflectance structural surface treatments and by using baffles and stops to limit this background noise. In 2007 GSFC researchers discovered that Multiwalled Carbon Nanotubes (MWCNTs) are exceptionally good absorbers, with potential to provide order-of-magnitude improvement over current surface treatments and a resulting factor of 10,000 reduction in stray light when applied to an entire optical train. Development of this technology will provide numerous benefits including: a.) simplification of instrument stray light controls to achieve equivalent performance, b.) increasing observational efficiencies by recovering currently unusable scenes in high contrast regions, and c.) enabling low-noise observations that are beyond current capabilities. Our objective was to develop and apply MWCNTs to instrument components to realize these benefits. We have addressed the technical challenges to advance the technology by tuning the MWCNT geometry using a variety of methods to provide a factor of 10 improvement over current surface treatments used in space flight hardware. Techniques are being developed to apply the optimized geometry to typical instrument components such as spiders, baffles and tubes. Application of the nanostructures to alternate materials (or by contact transfer) is also being investigated. In addition, candidate geometries have been tested and optimized for robustness to survive integration, testing, launch and operations associated with space flight hardware. The benefits of this technology extend to space science where observations of extremely dim objects require suppression of stray light.

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