CeFO-Related Publications

@article{falaggis_22,

title = {Freeform optics: Introduction},

author = {K. Falaggis and J. Rolland and F. Duerr and A. Sohn},

doi = {https://doi.org/10.1364/OE.454788},

year  = {2022},

date = {2022-02-14},

journal = {Optics Express},

volume = {30},

issue = {4},

pages = {6450-6455},

abstract = {This feature issue of Optics Express highlights 28 state-of-the-art articles that capture a snapshot of the recent developments in the field of freeform optics. As an introduction, the editors provide an overview of all published articles, which cover a broad range of topics in freeform optics. The wide variety of applications presented here demonstrates that freeform optics is a growing and vibrant field with many more innovations to come.},

keywords = {CeFO related},

pubstate = {published},

tppubtype = {article}

}

@article{Hu2021,

title = {Morphology and waveguiding properties of ultrafast-laser-inscribed type-II waveguides in IG2},

author = {W. Hu and M. Kilinc and W. Gebremichael and C. Dorrer, and J. Qiao},

year  = {2021},

date = {2021-12-24},

urldate = {2021-12-24},

journal = {Optical Materials Express},

volume = {12},

number = {1},

pages = {360-373},

abstract = {Ultrafast-laser-inscribed type-II waveguides inside the chalcogenide glass IG2 and the morphology of the inscribed tracks are presented for the first time to our knowledge. Self-organized periodic structures induced by the ultrafast laser in the tracks are characterized. The near-infrared waveguiding properties are studied for various pulse energies, durations, repetition rates, and polarization states, as well as different separations between the two written tracks. A propagation loss of ∼ 2.3 dB/cm is demonstrated in a type-II waveguide formed in IG2.},

keywords = {manufacturing, related},

pubstate = {published},

tppubtype = {article}

}

@article{Feng2021,

title = {Femtosecond-Laser-Ablation Dynamics in Silicon Revealed by Transient Reflectivity Change},

author = {T. Feng and G. Chen and H. Han and J. Qiao},

year  = {2021},

date = {2021-12-23},

journal = {Micromachines},

volume = {13},

number = {1},

abstract = {The dynamics of ablation in monocrystalline silicon, from electron-hole plasma generation to material expansion, upon irradiation by a single femtosecond laser pulse (1030 nm, 300 fs pulse duration) at a wide range of fluences is investigated using a time-resolved microscopy technique. The reflectivity evolution obtained from dynamic images in combination with a theoretical Drude model and a Two-Temperature model provides new insights on material excitation and ablation process. For all fluences, the reflectivity increased to a temporary stable state after hundreds of femtoseconds. This behavior was predicted using a temperature-dependent refractive index in the Drude model. The increase in velocity of plasma generation with increasing fluence was theoretically predicted by the Two-Temperature model. Two ablation regimes at high fluences (>0.86 J/cm2) were identified through the measured transient reflectivity and ablation crater profile. The simulation shows that the fluence triggering the second ablation regime produces a boiling temperature (silicon, 2628 K).},

keywords = {manufacturing, related},

pubstate = {published},

tppubtype = {article}

}

@article{papa_OE21,

title = {Survey of the four-mirror freeform imager solution space},

author = {J. C. Papa and J. M. Howard and J. P. Rolland},

doi = {https://doi.org/10.1364/OE.442943},

year  = {2021},

date = {2021-12-06},

journal = {Optics Express},

volume = {29},

issue = {25},

pages = {41534-41551},

abstract = {We present the results and methods of a survey of the four-mirror freeform imager solution space. This survey is a grid search over the parameters that remain after reducing the solution space’s degrees of freedom using first-, second-, and third-order aberration theory. We then optimize the systems’ higher-order surface shapes through sixth-order. Finally, we discuss general trends in the systems’ performance versus volume and etendue and their utility in trade studies.},

keywords = {CeFO related},

pubstate = {published},

tppubtype = {article}

}

@article{Swain2021,

title = {Telephoto-lens-based Optical Differentiation Wavefront Sensor for freeform metrology},

author = {BR Swain and C. Dorrer and J. Qiao},

year  = {2021},

date = {2021-11-03},

urldate = {2021-11-03},

journal = {Opt. Express},

volume = {29},

number = {23},

pages = {38395-38403},

abstract = {We report an Optical Differentiation Wavefront Sensor based on a telephoto lens system and binary pixelated filters. It provides a five-fold reduction in the system length compared to a 4f system with identical effective focal length. Measurements of phase plates with this system are compared to measurements performed with a commercial low-coherence interferometer. The telephoto-lens-based system can measure wavefronts with accuracy better than λ/10 Root Mean Squared (RMS) at λ=633 nm. Experimental investigation shows that the system has a high tolerance to components alignment errors.},

keywords = {metrology, related},

pubstate = {published},

tppubtype = {article}

}

@article{karci_NAT21,

title = {Experimental investigation of binodal astigmatism in nodal aberration theory (NAT) with a Cassegrain telescope system},

author = {O. Karci and E. Arpa and M. Ekinci and J. P. Rolland},

doi = {https://doi.org/10.1364/OE.427164},

year  = {2021},

date = {2021-06-21},

journal = {Optics Express},

volume = {29},

issue = {13},

pages = {19427-19440},

abstract = {We present simulations and an experimental investigation of binodal astigmatism in

nodal aberration theory (NAT) for a customized, high-precision Cassegrain telescope system. The

telescope system utilizes a five-axis, piezo-actuated flexural mechanism to introduce secondary

mirror misalignments and generate aberrations intentionally. The induced aberrations are

measured interferometrically and quantified for a grid of field points on the telescope system’s

image plane. For this purpose, a coma-free pivot point of the secondary mirror was simulated for

isolating the binodal astigmatism field response. The separation of the nodes is proportional to

the introduced misalignments. A simulation of Fringe Zernike coma and binodal astigmatism

was generated using a real ray trace model of the optical system and analyzed to compare to

the experimental results. A statistical analysis of the measurements was performed to show the

experimental results’ accuracy and stability. The experimental results were consistent with the

simulations, hence experimentally validating NAT for binodal astigmatism for the first time.

},

keywords = {CeFO related},

pubstate = {published},

tppubtype = {article}

}

@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}

}

@article{Horvath_2021a,

title = {Advancing lightweight mirror design: a paradigm shift in mirror preforms by utilizing design for additive manufacturing},

author = {Nicholas Horvath and Matthew Davies},

doi = {https://doi.org/10.1364/AO.410350},

year  = {2021},

date = {2021-01-18},

urldate = {2021-01-18},

journal = {Applied Optics},

volume = {60},

issue = {3},

pages = {681-696},

keywords = {CeFO related, manufacturing},

pubstate = {published},

tppubtype = {article}

}

@article{Sahoo2020,

title = {Dynamic pulse propagation modelling for predictive femtosecond-laser-microbonding of transparent materials},

author = {Pankaj K. Sahoo and Tao Feng and Jie Qiao},

year  = {2020},

date = {2020-10-02},

journal = {Opt. Express},

volume = {28},

number = {21},

pages = {31103-31118},

abstract = {A dynamic pulse propagation modeling for femtosecond laser bonding of Borofloat glass is presented. The temperature evolution and internal modifications are predicted by incorporating the nonlinear electron dynamics along with temperature dependent thermal properties. The modelling predicts the spatial and temporal distribution of absorption coefficient and plasma density that gives quantitative estimations of the heat affected zone and weld geometry. The impact of focusing condition on heat affected zone and weld geometry is investigated, which for the first time to our knowledge allows to numerically determine the desired relative position between the geometrical focus of a femtosecond-laser-pulse and the interface of the two substrates to be welded. The prediction of the modelling on the offset distance is applied to weld Borofloat glass plates having optical contact and can be applied to other dielectric solids.},

keywords = {manufacturing, related},

pubstate = {published},

tppubtype = {article}

}

@article{Horvath19-ab,

title = {Grinding of additively manufactured silicon carbide surfaces for optical applications},

author = {Nicholas Horvath and Andrew Honeycutt and Matthew A. Davies},

url = {https://doi.org/10.1016/j.cirp.2020.04.079},

year  = {2020},

date = {2020-05-19},

journal = {CIRP Annals},

volume = {69},

pages = {509-512},

abstract = {Many of the properties of Silicon carbide (SiC) are advantageous for optical applications, such as telescope mirrors and industrial laser systems. However, the base shapes of complex components are costly and difficult to manufacture. Leveraging additive manufacturing, near net complex components are readily processed. Here, we investigate the post processing of additively manufactured SiC (AM SiC) compared to chemical vapor deposited (CVD) SiC. The specific grinding energy for the AM SiC was lower than CVD, however the trends were the same. A specular finish was observed on both materials but the AM SiC finish was limited due to residual porosity.},

keywords = {manufacturing, related},

pubstate = {published},

tppubtype = {article}

}

@article{DeMars_02,

title = {Single-Shot Phase Calibration of a Spatial Light Modulator using Geometric Phase Interferometry},

author = {L. A. DeMars and M. Mikula-Zdankowska and K. Falaggis and R. Porras-Aguilar},

year  = {2020},

date = {2020-01-01},

journal = {Appl. Opt.},

keywords = {CEFO metrology, CeFO related},

pubstate = {published},

tppubtype = {article}

}

@article{Swain2019,

title = {High-performance optical differentiation wavefront sensing towards freeform metrology},

author = {Biswa Ranjan Swain and Christophe Dorrer and Jie Qiao},

year  = {2019},

date = {2019-12-09},

journal = {Opt. Express},

volume = {27},

number = {25},

pages = {36297-36310},

abstract = {We report the demonstration of freeform optics metrology with an optical differentiation wavefront sensor that relies on spatially dithered distributions of binary pixels to synthesize a far-field amplitude filter. Analysis of experimental results and comparison with a commercial low-coherence-length interferometer shows that freeform phase plates with different magnitude of wavefront slopes can be accurately characterized. RMS accuracy of ∼ λ/10 and precision of ∼ λ/70 at 633 nm were achieved with pixelated filters having 2.5-µm pixels. Simulations that describe the characterization of a freeform optical component in the presence of photodetection noise and filter nonlinearity demonstrate the robustness of this wavefront-sensing approach for freeform optics characterization.},

keywords = {CeFO related, metrology},

pubstate = {published},

tppubtype = {article}

}

@article{lineark,

title = {Absolute linear-in-k spectrometer designs enabled by freeform optics},

author = {C. Yoon and A. Bauer and D. Xu and C. Dorrer and J. P. Rolland},

url = {https://doi.org/10.1364/OE.27.034593},

year  = {2019},

date = {2019-11-25},

journal = {Optics Express},

volume = {27},

number = {24},

pages = {34593-34602},

abstract = {Linear-in-wavenumber, k, spectrometers have the merits of saving signal processing time and improving the sensitivity of spectral-domain optical coherence tomography (SD-OCT) by avoiding post-k-interpolation. We report on an approach leveraging freeform optics to linearize spectrometers in k to achieve an extremely low residual k-nonlinearity in design. A freeform lens reduced the k-nonlinearity from 2.47% for a benchmark spectrometer to 2.79 × 10−5% and 3.36 × 10−9% using the Fringe Zernike coefficients up to the 16th term and 37th term, respectively. A simulation model was developed to evaluate the performance of SD-OCT with the designed spectrometers. Without the k-interpolation in software, results show that the two freeform spectrometers achieve a roll-off gain of 5.24 dB over the imaging depth from 0.5 to 5.5 mm, while the maximum imaging depth is 5.8 mm. Finally, a 4.2-µm-FWHM axial PSF was maintained throughout the imaging depth in air.},

keywords = {CeFO related},

pubstate = {published},

tppubtype = {article}

}

@article{Alonso2019b,

title = {Effects on the OTF of MSF structures with random variations},

author = {Kevin Liang; Miguel A. Alonso },

doi = {10.1364/OE.27.034665},

year  = {2019},

date = {2019-11-11},

journal = {Optics Express},

volume = {27},

number = {24},

pages = {34665-34680},

abstract = {In diamond-machined freeform manufacturing processes, a tool-tip often leaves behind characteristic mid-spatial frequency (MSF) structures on the optical surface. Unwanted movement between the tool-tip and the part results in MSF structures with random variations. Here, we analyze the effects of these MSF structures on the system’s optical performance and derive simple analytic estimates for the optical transfer function in terms of the parameters of these structures. These expressions are expected to aid in MSF tolerancing.},

keywords = {CeFO design},

pubstate = {published},

tppubtype = {article}

}

@article{BauerARRI,

title = {All-reflective electronic viewfinder enable by freeform optics},

author = {A. Bauer and M. Pesch and J. Muschaweck and F. Leupelt and J. P. Rolland},

url = {https://doi.org/10.1364/OE.27.030597},

year  = {2019},

date = {2019-10-14},

journal = {Optics Express},

volume = {27},

number = {21},

pages = {30597-30605},

abstract = {Refractive eyepiece design forms are often limited by chromatic aberrations and require a mix of glass types to achieve sufficient correction, thus they are not conducive to manufacture in volume. Reflective surfaces are inherently achromatic and can be produced in volume, but rotationally symmetric reflective surfaces are either used with lossy obscurations or are incapable of correcting rotationally variant aberrations when used in an unobscured form. Freeform optics enable unobscured reflective design forms with excellent image quality. Here, we document the design, fabrication, and assembly of an all-reflective high-end electronic viewfinder that shows the applicability of freeform surfaces to eyepiece design forms.},

keywords = {CeFO design, CeFO related},

pubstate = {published},

tppubtype = {article}

}

@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}

}

@article{Feng2019,

title = {Pulse-Propagation Modeling and Experiment for Femtosecond-Laser Writing of Waveguide in Nd:YAG},

author = {Tao Feng and Pankaj K. Sahoo and Francisco R. Arteaga-Sierra and Christophe Dorrer and Jie Qiao},

year  = {2019},

date = {2019-08-20},

journal = {Crystals },

volume = {9},

number = {8},

pages = {434},

abstract = {In this work, unidirectional pulse propagation equation (UPPE) modeling is performed to study the nonlinear laser-mater interaction in silicon and Nd:Y3Al5O12 (Nd:YAG) crystals. The simulation results are validated with reported experimental results for silicon and applied to Nd:YAG crystals with experimental validation. Stress-induced waveguides are written in Nd:YAG crystals using 515 nm, 300 fs pulses at a 1 kHz repetition rate. Waveguides having a mean propagation loss of 0.21 ± 0.06 dB/cm are obtained, which is lower than the previous reported values for Type-II waveguides written in Nd:YAG crystals. The modeling and experimental results consistently show that the modification (waveguide track) depth increases with input energy. A detailed analysis is presented to control the modal properties of the waveguide in the context of UPPE simulation.},

keywords = {CeFO related, manufacturing},

pubstate = {published},

tppubtype = {article}

}

@article{ALONSOALEMAN2019,

title = {Study of reflectors for illumination via conformal maps},

author = {LUIS A. ALEMÁN-CASTAÑEDA AND MIGUEL A. ALONSO},

editor = {Optical Society of America },

doi = {https://doi.org/10.1364/OL.44.003809},

year  = {2019},

date = {2019-07-02},

journal = {Optics Letters},

volume = {44},

number = {15},

pages = {3809-3812},

abstract = {We present an approach for the study and design of reflectors with rotational or translational symmetry that redirect light from a point source into any desired radiant intensity distribution. This method is based on a simple conformal map that transforms the reflector’s shape into a curve that describes light’s direction after reflection. Both segmented reflectors and continuous reflectors are discussed, illustrating how certain reflector characteristics become apparent under this transformation. This method can also be used to study extended sources via translations.},

keywords = {design, related},

pubstate = {published},

tppubtype = {article}

}

@article{DeMars_01,

title = {Calibration of an SLM using Geometric Phase Interferometry},

author = {L. A. DeMars and K. Falaggis and R. Porras-Aguilar },

year  = {2019},

date = {2019-06-01},

journal = {RIAO-OPTILAS-MOPM},

keywords = {CEFO metrology, CeFO related},

pubstate = {published},

tppubtype = {article}

}

@article{Mishchik2019,

title = {High-efficiency femtosecond ablation of silicon with GHz repetition rate laser source},

author = {Konstantin Mishchik and Guillaume Bonamis and Jie Qiao and John Lopez and Eric Audouard and Eric Mottay and Clemens Hönninger and Inka Manek-Hönninger},

year  = {2019},

date = {2019-05-01},

journal = {Opt. Lett.},

volume = {44},

number = {9},

pages = {2193-2196},

abstract = {We report on silicon ablation with a 20 W GHz amplified femtosecond laser source. This novel laser delivers burst energies up to 400 μJ, providing flexible intra-pulse repetition rates of 0.88 or 3.52 GHz, up to 200 pulses with ∼350 fs pulse duration. High-efficiency, high-quality ablation can be achieved through optimally determining the number of pulses, intra-pulse repetition, and average pulse energy within a burst. Due to such optimization, we demonstrate a specific ablation rate of 2.5 mm3∕ min ∕W with a burst containing 200 pulses at 0.88 GHz, which is the highest one reported so far for fs laser ablation, to the best of our knowledge. GHz ablation is sensitive to the selection of laser parameters. We conceptually discuss the contributions of the pulses within a burst to heat-accumulation-based incubation and material ablation.},

keywords = {CeFO related, manufacturing},

pubstate = {published},

tppubtype = {article}

}

@article{ALEMÁN-CASTANEDA2019,

title = {Shearing interferometry via geometric phase},

author = {LUIS A. ALEMÁN-CASTANEDA, BRUNO PICCIRILLO, ENRICO SANTAMATO, LORENZO MARRUCCI, AND MIGUEL A. ALONSO},

url = {https://doi.org/10.1364/OPTICA.6.000396},

doi = {10.1364/OPTICA.6.000396},

year  = {2019},

date = {2019-03-21},

journal = {Optica},

volume = {6},

number = {4},

pages = {396-399},

abstract = {We propose an approach based on geometric phase for per- forming several types of shearing interferometry through a ro- bust, compact, common-path setup. The key elements are two identical parallel plates with spatially varying birefringence distributions, which perform the shearing by writing opposite geometric phases on the two circular polarization components of the linearly polarized incident wavefront. This setup allows the independent control of the shearing magnitude and rela- tive phase of the two wavefront replicas. The approach is first illustrated for the simplest case of lateral shearing, and then extended to other geometries where the magnitude and direc- tion of the shear vary smoothly over the wavefront.},

keywords = {metrology, related},

pubstate = {published},

tppubtype = {article}

}

@article{Schiesser2018,

title = {Gaussian curvature and stigmatic imaging relations for the design of an unobscured reflective relay},

author = {Eric M. Schiesser and Seung-Whan Bahk and Jake Bromage and Jannick P. Rolland},

url = {https://doi.org/10.1364/OL.43.004855},

doi = {10.1364/OL.43.004855},

year  = {2018},

date = {2018-10-03},

journal = {Optics Letters},

number = {20},

pages = {4855-4858},

abstract = {We derive the relationship between Coddington's equations and the Gaussian curvature for a stigmatic reflective imaging system. This relationship allows parameterizing off-axis conic optical systems using traditional first-order optics by considering the effective curvature at the center of the off-axis sections. Specifically, we demonstrate parameterizing the system requirements of a 2{texttimes} achromatic image relay for a terawatt laser system. This system required both collimation (far-field) and pupil imaging (near-field) simultaneously. Long working distances and specific spatial constraints limited the available layout options for the imaging components. By parameterizing these system requirements and packaging constraints, the final specifications could be quickly iterated, while allowing for flexibility in the layout of the system during a multi-year conceptual period.},

keywords = {CeFO related, design},

pubstate = {published},

tppubtype = {article}

}

@article{Papa_IODC2017,

title = {Starting point designs for freeform four-mirror systems},

author = {Jonathan C. Papa and J. Howard and J. P. Rolland},

url = {https://doi.org/10.1117/1.OE.57.10.101705},

doi = {10.1117/1.OE.57.10.101705},

year  = {2018},

date = {2018-06-21},

journal = {Optical Engineering},

volume = {57},

number = {10},

pages = {101705},

abstract = {Driven by the development of freeform four-mirror solutions, we review and compare analytical methods to generate starting point designs with various states of correction, surface types, symmetry, and obscuration. The advantages and disadvantages of each are examined. We have combined several concepts and techniques from the literature to analytically generate unobscured freeform starting point designs that are corrected through the third-order image degrading aberrations. The surfaces in these starting point designs are described as base off-axis conics that image stigmatically for the central field point, also known as Cartesian reflectors, with an aspheric departure “cap” (quartic with the aperture) added to the Cartesian reflectors. Tilt angles are chosen to cancel field-asymmetric field-linear astigmatism and unobscure the system. Paraxial data from an equivalent on-axis system are used to solve a system of linear equations to determine the magnitude of the aspheric departure “caps” that are placed on top of the base Cartesian reflectors, in order to eliminate the remaining third-order image degrading aberrations. In this approach, each aspheric departure “cap” is centered about the intersection of the optical-axis-ray, also known as the base ray, with the base surface, rather than being centered about the axis of rotational invariance.},

keywords = {CeFO related, design},

pubstate = {published},

tppubtype = {article}

}

@article{LaurenApp18,

title = {Direct binary search for improved beam shaping and optical differentiation wavefront sensing},

author = {C. Dorrer and J. Qiao},

doi = {https://www.osapublishing.org/ao/abstract.cfm?URI=ao-57-29-8557},

year  = {2018},

date = {2018-06-01},

journal = {Applied Optics},

volume = {57 (29)},

pages = {8557-8565 },

keywords = {CeFO related, manufacturing, related},

pubstate = {published},

tppubtype = {article}

}