Dr. Henry Quach Profile

Dr. Henry Quach

at ASML San Diego

SPIE Involvement:

Author

Publications (11)

Proceedings Article | 4 October 2023 Presentation + Paper

Advanced deflectometry methods for industrial application

Heejoo Choi, Hyukmo Kang, Yiyang Huang, Mina Yoo, Henry Quach, John Kam, Daewook Kim

Proceedings Volume 12684, 1268407 (2023) https://doi.org/10.1117/12.2678628

KEYWORDS: Deflectometry, Optical alignment, Image processing, Optical testing, Dark field illumination, Industrial applications

Read Abstract +

Deflectometry is a versatile optical testing tool used in various fields, from astronomy to industrial applications, due to its non-null testing capability which facilitates precise measurement despite challenging optical surfaces and system layout constraints. In this manuscript, we present novel variational advancements to traditional deflectometry, towards universal functionality and system friendliness. Traditional dark-field illumination is an inspection technique that is sometimes used to detect particles on a specular surface. Problems arise in its repeatability, as an intensity-based measurement is vulnerably dependent on the testing conditions of time, limiting its ability to be used in automated fashion. The first advancement leverages phase algorithms commonly seen in deflectometry; by adding a secondary light source (normal to the surface) and modulating each source's intensity with a time-varying sinusoid. The phase-based information has a higher sensitivity to the light scattered from a defect producing a more robust computational image process method that is now insensitive to the environment. The second advancement is an alignment method to obtain lower-order shape. While deflectometry proves effective in measuring mid-to-high frequency surface shape, it faces challenges when assessing low-order shape measurements like power, astigmatism, and coma due to relative position and alignment error between the unit under test (UUT) and the deflectometry system. To avert the necessity of additional instruments like a coordinate measuring machine, laser trackers, or interferometers, we leveraged computational fiducials and sensitivity matrices to identify and address misalignments effectively. With enhanced capabilities and system-friendly features, our advanced deflectometry techniques provide powerful options in optical testing. By addressing the challenges in low-order shape measurements and incorporating dark field testing, our approaches extend the potential of deflectometry as a valuable tool in optical metrology across a broad spectrum of industries and scientific endeavors.

Proceedings Article | 3 October 2022 Presentation + Paper

Influence of lens and perspective distortion on optical surface metrology instrumentation

Henry Quach, Joel Berkson, Hyukmo Kang, Heejoo Choi, Daewook Kim

Proceedings Volume 12221, 122210M (2022) https://doi.org/10.1117/12.2633090

KEYWORDS: Distortion, Metrology, Imaging systems, Image processing, Cameras, Calibration

Read Abstract +

Proceedings Article | 27 August 2022 Presentation + Paper

Orbiting astronomical satellite for investigating stellar systems (OASIS): a paradigm shift in realizing large space telescopes

Siddhartha Sirsi, Christopher Walker, Jonathan Arenberg, Yuzuru Takashima, Daewook Kim, Heejoo Choi, Arthur Palisoc, Henry Quach, Marcos Esparza, Kevin Derby, Luke Mayer, Tianyao Zhang, Aman Chandra, Anthony Stark

Proceedings Volume 12180, 121801Q (2022) https://doi.org/10.1117/12.2629100

KEYWORDS: Space telescopes, Receivers, Astronomy, Optical design, Satellites, Mirrors, Cryogenics, Space operations, Metrology, LIDAR

Read Abstract +

Proceedings Article | 24 August 2021 Open Access

Deflectometry-based thermal vacuum testing for a pneumatic terahertz antenna

Henry Quach, Marcos Esparza, Hyukmo Kang, Aman Chandra, Heejoo Choi, Joel Berkson, Karlene Karrfalt, Siddhartha Sirsi, Yuzuru Takashima, Art Palisoc, Jonathan Arenberg, Kristy Gogick Marshall, Christopher Glynn, Sean Godinez, Marcos Tafoya, Christopher Walker, Christian Drouet d'Aubigny, Daewook Kim

Proceedings Volume 11820, 118200W (2021) https://doi.org/10.1117/12.2594902

KEYWORDS: Deflectometry, Calibration, Cameras, Antennas, Metrology

Read Abstract +

DOWNLOAD PAPER

Proceedings Article | 24 August 2021 Open Access

Analytical and finite element analysis tool for nonlinear membrane antenna modeling for astronomical applications

Arthur Palisoc, Gerard Pardoen, Yuzuru Takashima, Aman Chandra, Siddharta Sirsi, Heejoo Choi, Daewook Kim, Henry Quach, Jonathan Arenberg, Christopher Walker

Proceedings Volume 11820, 118200U (2021) https://doi.org/10.1117/12.2594050

KEYWORDS: Reflectors, Finite element methods, James Webb Space Telescope, Telescopes, Mirrors, Antennas, Inverse problems

Read Abstract +

The uninflated shape configurations of parabolic and spherical membrane mirrors were calculated by solving the inverse problem, i.e., given the design inflation pressure, the membrane material and geometric properties, what must be the initial uninflated shape such that on inflation to the design pressure, the exact desired surface of revolution is obtained. The resulting first order nonlinear differential equation was numerically integrated using the boundary conditions. The initial uninflated shape was then subjected to a forward transformation using FAIM, a proprietary geometric nonlinear membrane finite element code. FAIM has been validated against exact analytical solutions for both small and extremely large deformations that are up to eight orders of magnitude larger compared with the starting undeflected shape. Simulations reveal that to fabricate a very accurate and precise inflated membrane mirror relative to the design parameters, one must not only accurately measure and input the moduli in both meridional and hoop directions but an accurately measured Poisson’s ratio as well. The code was used to guide the membrane mirror design. For very small aperture diameters, the initial uninflated shape may be fabricated by thermo-forming the membrane. For aperture diameters exceeding one meter however, the membrane mirror is built with discrete gores that are joined together with tapes at the seams. This provided the impetus to write a companion computer code FLATE, to calculate the gore shapes using a slight modification of the solution to the inverse transformation equation to account for the presence of the seam tapes. After the gores were determined, the resulting final inflated shape was calculated and verified using FAIM. Sensitivity analyses can now be carried out to determine the resulting surface shape as a function of the different sources of error: gore width, gore length, perimeter attachment uncertainties, thermal effects, variation of material properties over the membrane continuum and inflation pressure changes. The code has been shown to be more robust than equivalent commercial analytical packages in so far as membrane, cable and space-frame element combinations are concerned. In particular, the analytical and finite element codes were used in the preliminary assessment of a membrane optic for the OASIS Mission (Orbiting Astronomical Satellite for Investigating Stellar Systems) [1]. The OASIS is a 20-meter class space observatory operating at high spectral resolution in the terahertz frequencies. Over its nominal 2-year mission it will probe conditions and search for biogenic molecules on hundreds of protoplanetary disks and other solar system objects.

DOWNLOAD PAPER

Proceedings Article | 24 August 2021 Open Access

Stressed deformable reflector design and pneumatic membrane antenna for cryogenic thermal vacuum chamber testing

Marcos Esparza, Heejoo Choi, Hyukmo Kang, Christian d'Aubigny, Amarjiit Pandde, Henry Quach, Aman Chandra, Karlene Karrfalt, Yuzuru Takashima, Art Palisoc, Jonathan Arenberg, Kristy Gogick Marshall, Christopher Glynn, Sean Godinez, Marcos Tafoya, Brandon Chalifoux, Christopher Walker, Daewook Kim

Proceedings Volume 11820, 118200R (2021) https://doi.org/10.1117/12.2594403

KEYWORDS: Actuators, Reflectors, Computer aided design, Antennas, Prototyping, Polonium, Reflector design, Aluminum, Wavefronts, Solid modeling

Read Abstract +

DOWNLOAD PAPER

Proceedings Article | 15 January 2021 Paper

Optical technology for future telescopes

Dae Wook Kim, Marcos Esparza, Henry Quach, Stephanie Rodriguez, Hyukmo Kang, Yi-Ting Feng, Heejoo Choi

Proceedings Volume 11761, 1176103 (2021) https://doi.org/10.1117/12.2586867

Read Abstract +

Proceedings Article | 20 August 2020 Presentation + Paper

Full-aperture optical metrology for inflatable membrane mirrors

Henry Quach, Joel Berkson, Siddhartha Sirsi, Heejoo Choi, Ruben Dominguez, Brian Duffy, David Lesser, Yuzuru Takashima, Art Palisoc, Christopher Walker, Dae Wook Kim

Proceedings Volume 11487, 114870N (2020) https://doi.org/10.1117/12.2569750

KEYWORDS: Deflectometry, Metrology, Reflectors, Photogrammetry, Telescopes

Read Abstract +

Proceedings Article | 20 August 2020 Presentation + Paper

Computational alignment of on-machine deflectometry

Hyukmo Kang, Henry Quach, Heejoo Choi, Greg Smith, Dae Wook Kim

Proceedings Volume 11487, 114870O (2020) https://doi.org/10.1117/12.2576955

KEYWORDS: Deflectometry, Computer simulations, Sensors, Calibration, Cameras, Optical alignment, Measurement devices, Ray tracing

Read Abstract +

Proceedings Article | 20 August 2020 Presentation + Paper

Non-planar illumination sources for deflectometry

Henry Quach, Hyukmo Kang, Heejoo Choi, Dae Wook Kim

Proceedings Volume 11487, 114870L (2020) https://doi.org/10.1117/12.2568168

KEYWORDS: Deflectometry, Optics manufacturing, Prototyping, Light sources

Read Abstract +

Proceedings Article | 7 April 2020 Paper

Reconfigurable dynamic optical system design, test, and data analysis

Dae Wook Kim, Maham Aftab, Isaac Trumper, Logan Graves, Henry Quach, Hyukmo Kang, Hyemin Yoo, Andrew Lowman, Greg Smith, Matt Dubin, Chang-Jin Oh, Justin Hyatt, Christian Davila-Peralta, Heejoo Choi

Proceedings Volume 11352, 1135202 (2020) https://doi.org/10.1117/12.2555650

KEYWORDS: Deflectometry, Freeform optics, Optical testing, Optical design, Optics manufacturing, Infrared radiation, Metrology, Data analysis, Mirrors

Read Abstract +

Showing 5 of 11 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years