2021
Nikolov, Daniel K.; Bauer, Aaron; Cheng, Fei; Kato, Hitoshi; Vamivakas, A. Nick; Rolland, Jannick P.
Metaform optics: Bridging nanophotonics and freeform optics Journal Article
In: Science Advances, vol. 7, no. 18, pp. eabe5112, 2021.
Abstract | Links | BibTeX | Tags: Aberration correction, augmented reality, CeFO manufacturing, CEFO metrology, freeform, head display, Image quality, Optical design, relay optics, rolland, tomography
@article{nokey,
title = {Metaform optics: Bridging nanophotonics and freeform optics},
author = {Daniel K. Nikolov and Aaron Bauer and Fei Cheng and Hitoshi Kato and A. Nick Vamivakas and Jannick P. Rolland},
url = {https://www.science.org/doi/abs/10.1126/sciadv.abe5112},
doi = {10.1126/sciadv.abe5112},
year = {2021},
date = {2021-04-30},
urldate = {2021-04-30},
journal = {Science Advances},
volume = {7},
number = {18},
pages = {eabe5112},
abstract = {The demand for high-resolution optical systems with a compact form factor, such as augmented reality displays, sensors, and mobile cameras, requires creating new optical component architectures. Advances in the design and fabrication of freeform optics and metasurfaces make them potential solutions to address the previous needs. Here, we introduce the concept of a metaform—an optical surface that integrates the combined benefits of a freeform optic and a metasurface into a single optical component. We experimentally realized a miniature imager using a metaform mirror. The mirror is fabricated via an enhanced electron beam lithography process on a freeform substrate. The design degrees of freedom enabled by a metaform will support a new generation of optical systems.},
keywords = {Aberration correction, augmented reality, CeFO manufacturing, CEFO metrology, freeform, head display, Image quality, Optical design, relay optics, rolland, tomography},
pubstate = {published},
tppubtype = {article}
}
The demand for high-resolution optical systems with a compact form factor, such as augmented reality displays, sensors, and mobile cameras, requires creating new optical component architectures. Advances in the design and fabrication of freeform optics and metasurfaces make them potential solutions to address the previous needs. Here, we introduce the concept of a metaform—an optical surface that integrates the combined benefits of a freeform optic and a metasurface into a single optical component. We experimentally realized a miniature imager using a metaform mirror. The mirror is fabricated via an enhanced electron beam lithography process on a freeform substrate. The design degrees of freedom enabled by a metaform will support a new generation of optical systems.
2019
JING XU LAUREN L. TAYLOR, MICHAEL POMERANTZ; QIAO, JIE
Femtosecond laser polishing of germanium Journal Article
In: Optical Materials Express, vol. 9, no. 11, pp. 4165-4177, 2019.
Abstract | Links | BibTeX | Tags: CeFO manufacturing, CEFO metrology, fabrication, Freeform surfaces, manufacturing, Mid-Spatial Frequency error
@article{TAYLOR2019,
title = {Femtosecond laser polishing of germanium},
author = {LAUREN L. TAYLOR, JING XU, MICHAEL POMERANTZ, THOMAS
R. SMITH, JOHN C. LAMBROPOULOS, AND JIE QIAO},
url = {https://doi.org/10.1364/OME.9.004165},
year = {2019},
date = {2019-10-02},
journal = {Optical Materials Express},
volume = {9},
number = {11},
pages = {4165-4177},
abstract = {Freeform optics can reduce the cost, weight, and size of advanced imaging systems,
but it is challenging to manufacture the complex rotationally asymmetric surfaces to optical
tolerances. To address the need for disruptive, high-precision sub-aperture forming and finishing
techniques for freeform optics, we investigate an alternative, non-contact polishing methodology
using femtosecond lasers, combining modeling, experiments, and demonstrations. Femtosecondlaser-
based polishing of germanium was investigated using an experimentally-validated twotemperature
model of laser/germanium interaction to guide the understanding and selection of
laser parameters to achieve near-nonthermal ablation for polishing and figuring. For the first time
to our knowledge, model-guided femtosecond laser polishing of germanium was successfully
demonstrated, achieving precision material removal while maintaining single-digit nanometer
optical surface quality. The demonstrated femtosecond-laser-based polishing technique lays the
foundation for semiconductor optics polishing/fabrication using femtosecond lasers and opens a
viable path for high-precision, complex sub-aperture optical polishing tasks on various materials.},
keywords = {CeFO manufacturing, CEFO metrology, fabrication, Freeform surfaces, manufacturing, Mid-Spatial Frequency error},
pubstate = {published},
tppubtype = {article}
}
Freeform optics can reduce the cost, weight, and size of advanced imaging systems,
but it is challenging to manufacture the complex rotationally asymmetric surfaces to optical
tolerances. To address the need for disruptive, high-precision sub-aperture forming and finishing
techniques for freeform optics, we investigate an alternative, non-contact polishing methodology
using femtosecond lasers, combining modeling, experiments, and demonstrations. Femtosecondlaser-
based polishing of germanium was investigated using an experimentally-validated twotemperature
model of laser/germanium interaction to guide the understanding and selection of
laser parameters to achieve near-nonthermal ablation for polishing and figuring. For the first time
to our knowledge, model-guided femtosecond laser polishing of germanium was successfully
demonstrated, achieving precision material removal while maintaining single-digit nanometer
optical surface quality. The demonstrated femtosecond-laser-based polishing technique lays the
foundation for semiconductor optics polishing/fabrication using femtosecond lasers and opens a
viable path for high-precision, complex sub-aperture optical polishing tasks on various materials.
but it is challenging to manufacture the complex rotationally asymmetric surfaces to optical
tolerances. To address the need for disruptive, high-precision sub-aperture forming and finishing
techniques for freeform optics, we investigate an alternative, non-contact polishing methodology
using femtosecond lasers, combining modeling, experiments, and demonstrations. Femtosecondlaser-
based polishing of germanium was investigated using an experimentally-validated twotemperature
model of laser/germanium interaction to guide the understanding and selection of
laser parameters to achieve near-nonthermal ablation for polishing and figuring. For the first time
to our knowledge, model-guided femtosecond laser polishing of germanium was successfully
demonstrated, achieving precision material removal while maintaining single-digit nanometer
optical surface quality. The demonstrated femtosecond-laser-based polishing technique lays the
foundation for semiconductor optics polishing/fabrication using femtosecond lasers and opens a
viable path for high-precision, complex sub-aperture optical polishing tasks on various materials.
2016
Shahinian, H.; Cherukuri, H.; Mullany, B.
An Evaluation of Fiber-Based Tools for Glass Polishing Using Experimental and Computational Approaches Journal Article
In: Applied Optics, vol. 45, no. 16, pp. 4307-4316, 2016.
Abstract | Links | BibTeX | Tags: CeFO manufacturing
@article{Shahinian16,
title = {An Evaluation of Fiber-Based Tools for Glass Polishing Using Experimental and Computational Approaches},
author = {Shahinian, H. and H. Cherukuri and B. Mullany},
doi = {https://doi.org/10.1364/AO.55.004307},
year = {2016},
date = {2016-06-01},
urldate = {2016-06-01},
journal = {Applied Optics},
volume = {45},
number = {16},
pages = {4307-4316},
abstract = {Polymeric pad or pitch-based tools combined with loose abrasive slurries are typically used in the polishing of optical materials. In this paper, the potential of fiber-based tools to both remove material and provide high quality surface finishes on BK7 glass is explored. The potential advantage of fiber-based tools over traditional tools is their inherent compliance, which could accommodate varying workpiece surface curvatures as found in aspheres and freeforms. To evaluate the new tools, both experimental and finite element (FE) modeling approaches were taken. A FE model consisting of a single fiber engaged with the workpiece surface was used to estimate the shape and magnitude of the pressure distribution exerted by the fiber on the workpiece surface. Two different tool configurations, yielding two different Fes, predicted pressure distributions, were used to polish BK7 samples, and the material removal profiles were interferometrically measured. The resulting profiles and the predicted pressure distributions share the same v-shape. While differences in scale exist between the experimental and FE-predicted profiles, the tool generating higher material removal had the greater predicted pressure distribution, thus demonstrating the ability of the FE model to provide insights into tool design. Additional testing was conducted to determine if the tool’s removal rate can be predicted by Preston’s equation. Initial results indicate the equation is valid within the range of parameters tested. The surface roughness of BK7 samples processed by this tool was measured and some deterioration on the Sq value was noted; the surface roughness increased from 1.89 to 3.66 nm Sq. Over several hours of continuous use, the load applied by the fibers decays in a repeatable manner, and little wear was observed on the fibers after 5.33 h of polishing.},
keywords = {CeFO manufacturing},
pubstate = {published},
tppubtype = {article}
}
Polymeric pad or pitch-based tools combined with loose abrasive slurries are typically used in the polishing of optical materials. In this paper, the potential of fiber-based tools to both remove material and provide high quality surface finishes on BK7 glass is explored. The potential advantage of fiber-based tools over traditional tools is their inherent compliance, which could accommodate varying workpiece surface curvatures as found in aspheres and freeforms. To evaluate the new tools, both experimental and finite element (FE) modeling approaches were taken. A FE model consisting of a single fiber engaged with the workpiece surface was used to estimate the shape and magnitude of the pressure distribution exerted by the fiber on the workpiece surface. Two different tool configurations, yielding two different Fes, predicted pressure distributions, were used to polish BK7 samples, and the material removal profiles were interferometrically measured. The resulting profiles and the predicted pressure distributions share the same v-shape. While differences in scale exist between the experimental and FE-predicted profiles, the tool generating higher material removal had the greater predicted pressure distribution, thus demonstrating the ability of the FE model to provide insights into tool design. Additional testing was conducted to determine if the tool’s removal rate can be predicted by Preston’s equation. Initial results indicate the equation is valid within the range of parameters tested. The surface roughness of BK7 samples processed by this tool was measured and some deterioration on the Sq value was noted; the surface roughness increased from 1.89 to 3.66 nm Sq. Over several hours of continuous use, the load applied by the fibers decays in a repeatable manner, and little wear was observed on the fibers after 5.33 h of polishing.