Raymond Rumpf

Raymond Rumpf
University of Texas at El Paso | UTEP · Department of Electrical and Computer Engineering

PhD
Developing revolutionary technologies in electromagnetics, photonics, and hybrid 3D printing.

About

106
Publications
191,671
Reads
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1,951
Citations
Citations since 2016
46 Research Items
1465 Citations
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2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Introduction
I founded the EM Lab at the University of Texas at El Paso with a mission to develop revolutionary technologies that are enabled by digital manufacturing (i.e. 3D printing). Research includes 3D printed circuits, electromagnetics, metamaterials, photonic crystals, antennas, frequency selective surfaces, diffractive optics, nanophotonics, devices for high power microwaves, computational electromagnetics, and more. http://emlab.utep.edu/
Additional affiliations
January 2022 - January 2022
EMPossible
Position
  • Professor
Description
  • https://empossible.net/ -- Develops online course content in the areas of computation and electromagnetics, but also offer materials on career advice and graduate studies. Online courses are primarily free to the public, but several paid courses are available that offer next-level course instruction on advanced topics to the beginner.
January 2021 - January 2022
Kraetonics LLC
Position
  • Founder & Chief Technology Officer
Description
  • http://www.kraetonics.com/ -- Company offers advanced capabilities for slicing and hybrid 3D printing. OmniFAB(TM) can slice multiple material parts, drive hybrid 3D printers, perform off-axis printing, perform conforming printing, print devices composed of functionally graded materials, and more.
September 2010 - January 2022
University of Texas at El Paso
Position
  • Professor (Full)
Description
  • Research -- My lab develops disruptive technologies in electromagnetics, photonics, and hybrid 3D printing. Visit my research website at https://raymondrumpf.com/. Teaching -- I teach undergraduate and graduate courses in electromagnetics and computation. Visit my academic website at https://empossible.net/. Service -- I serve in numerous committees, am an associate editor for SPIE Optical Engineering, and I offer free course material to public.
Education
January 2001 - August 2006
University of Central Florida
Field of study
  • Optics
June 1995 - December 1997
Florida Institute of Technology
Field of study
  • Electrical Engineering
September 1990 - May 1995
Florida Institute of Technology
Field of study
  • Electrical Engineering

Publications

Publications (106)
Article
Full-text available
In this work, results are given for controlling waves arbitrarily inside a new type of spatially variant lattice. To demonstrate the concept, an unguided beam was made to flow around a 90° bend without diffracting or scattering. Control of the field was achieved by spatially varying the orientation of the unit cells throughout a self-collimating ph...
Article
Full-text available
Guided-mode resonance flters (GMRFs) are highly compact structures that can produce a strong frequency response from a single thin layer of dielectric. When a GMRF is formed onto a curved surface, the local angle of incidence varies over the aperture of the device and the overall performance significantly degrades. In the present work, we spatially...
Article
Full-text available
The near-field surrounding devices can be arbitrarily sculpted if they are embedded in a spatially variant anisotropic metamaterial (SVAM). Our SVAMs are low loss because they do not contain metals and are extraordinarily broadband, working from DC up to a cutoff. In the present work, a microstrip transmission line was isolated from a metal object...
Article
Full-text available
3D printing is an emerging technology in manufacturing. It is the long-term goal of the industry to print complex and fully functional products from cell phones to vehicles. A drawback of many 3D printing technologies is rough surface finish. It is known that metals with high surface roughness severely degrade the propagation of electromagnetic wav...
Article
Full-text available
It is often desired to functionally grade and/or spatially vary a periodic structure like a photonic crystal or metamaterial, yet no general method for doing this has been offered in the literature. A straightforward procedure is described here that allows many properties of the lattice to be spatially varied at the same time while producing a fina...
Conference Paper
Full-text available
We present a tunable planar guided-mode resonance (GMR) filter using time-varying permittivity along grating nanobars. Results show that the effective medium concept in the temporal state is exactly the same as the spatial state. Furthermore, the structure has spatial periodicity to save the resonance peak of the passive GMR in addition to the temp...
Presentation
Full-text available
چند وقت پیش، پروژه جالبی را شروع کردم که به آن سنگ روزتا الکترومغناطیسی می‌گوییم (سنگ روزتا: سنگ نوشته ای از دوران مصر باستان به سه زبان دنیا) که در آن پروژه، ویدیوی «دنیای شگفت‌انگیز الکترومغناطیس» ، به هرچه بیشتر زبان‌های ممکن ترجمه می‌شود. این ویدیو شامل معرفی و مروری جالب از الکترومغناطیس و فوتونیک است که برای دانش آموزان دبیرستانی و شاگردان جد...
Preprint
Full-text available
We present a general approach for numerical mode analysis of the multilayer slab waveguides using the scattering matrix (SM) instead of the conventional numerical methods. To calculate the global scattering matrix of multilayer structures, we apply the concept used in the transfer matrix method (TMM), which entails working through the device one la...
Article
Full-text available
A new numerical method to generate spatially variant lattices (SVLs) is derived and implemented. The algorithm proposed solves the underlying partial differential equations iteratively with an update equation derived using the finite-difference method to obtain an SVL that is continuous, smooth, and free of unintended defects while maintaining the...
Article
A binary-lens-embedded photonic crystal (B-LEPC) was designed for operation at 1550 nm and fabricated by multiphoton lithography. The lens is binary in the sense that optical path difference is generated using unit cells having just two distinct fill factors. The unit cells have a “rod-in-wall” structure that exhibits three-dimensional self-collima...
Article
Full-text available
We present an emulation design method for converting asymmetrical transmitters to nonreciprocal isolators equipped with time-varying metasurfaces. To illustrate the model, we design a structure using a combination of the photonic crystal (PhC) and time-varying metasurface. Moreover, we propose a general approach for numerical analysis of the time-m...
Article
Photonic crystals can be engineered so that the flow of optical power and the phase of the field are independently controlled. The concept is demonstrated by creating a self-collimating lattice with an embedded cylindrical lens. The device is fabricated in a photopolymer by multi-photon lithography with the lattice spacing chosen for operation arou...
Book
Full-text available
This book teaches the art and techniques of computational electromagnetics to the complete beginner using finite-difference frequency-domain in MATLAB. Book covers everything from the basic concepts up to advanced 3D simulations and anisotropic materials. Simulation examples (including full MATLAB codes) include waveguides, surface waves, transmiss...
Article
Full-text available
We present a general approach for numerical mode analysis of the multilayer slab waveguides using the scattering matrix (SM) instead of the conventional numerical methods. To calculate the global scattering matrix of multilayer structures, we apply the concept used in the transfer matrix method (TMM), which entails working through the device one la...
Article
An algorithm is introduced for generating frequency selective surfaces (FSS) capable of conforming to any curvature while maintaining proper size, shape and spacing of the elements. Compared to traditional projection and mapping methods, the presented algorithm maintains the electromagnetic properties of the FSS array despite the curvature. The alg...
Preprint
Full-text available
We present an emulation design method for converting asymmetric isolators to nonreciprocal ones using time-varying metasurfaces. To illustrate the model, we design a structure using a combination of the photonic crystal (PhC) and time-varying metasurface. Moreover, we propose a general approach for numerical analysis of the time-modulated proposed...
Article
Full-text available
We introduce two-dimensional space plus time (2D+1) structure and numerically investigate it using a developed multilayer simulation framework, for the first time. The new structure is consisting of crossed grating with time-varying permittivity which is inspired from 1D+1. In this regard, we extend Fourier Modal Method (FMM) in a general approach...
Preprint
Full-text available
We present a general approach for numerical mode analysis of the multilayer slab waveguides using the Transfer Matrix Method (TMM) instead of the Finite Difference Frequency Domain (FDFD) method. TMM consists of working through the device one layer at a time and calculating an overall transfer matrix. Using the scattering matrix technique, we devel...
Conference Paper
Full-text available
We present a general approach for numerical mode analysis of the multilayer slab waveguides using the Transfer Matrix Method (TMM) instead of the Finite Difference Frequency Domain (FDFD) method. TMM consists of working through the device one layer at a time and calculating an overall transfer matrix. Using the scattering matrix technique, we devel...
Article
Full-text available
Statement of problem Selective laser melting (SLM), an additive manufacturing technology, is expected to replace the traditional lost-wax casting process used in producing removable partial denture (RPD) frameworks. However, studies comparing the accuracy of RPD frameworks and the effects of process parameters are lacking. Purpose The purpose of t...
Article
Wide-angle, broadband self-collimation (SC) is demonstrated in a hexagonal photonic crystal (PhC) fabricated in a low-refractive-index photopolymer by multiphoton lithography. The PhC can be described as a hexagonal array of cylindrical air holes in a block of dielectric material having a low-refractive index. Optical characterization shows that th...
Conference Paper
We present a device that flows a beam incident at any position and angle along the input side of a lattice to a single zone at the output. We report the performance of the device.
Article
Full-text available
Design of the guided-mode resonance (GMR) grating filter, as one of the most important optical components, using the cultural algorithm (CA) is presented, for the first time. CA is an evolutionary algorithm (EA) which is easy-to-implement, flexible, inspired by the human cultural evolution, upon using the domain knowledge for reducing the search sp...
Article
We propose an optimized method for the inverse design of guided-mode resonance (GMR) filters using one- and two- dimensional (1D & 2D) grating structures. This work for 2D state is based on developing the effective permittivity of 1D grating structures along three orthogonal axes to predict the physical dimensions of the structure, for the first ti...
Article
Full-text available
Spatial transform techniques like transformation optics and conformal mapping have arisen as the dominant techniques for designing metamaterial devices. However, these techniques only produce the electrical permittivity and permeability as a function of position. The manner in which these functions are converted into physical metamaterial lattices...
Article
Self-collimating photonic crystals are a promising technology to control waves in optical devices. A technique was recently developed that can bend, twist, and otherwise spatially vary a photonic crystal without deforming the unit cells, as this would weaken or destroy the optical properties. Applying this to self-collimating photonic crystals allo...
Article
In this work, a completely automated CAD-to-print process flow for hybrid direct-write 3D printing was produced. We adapted this capability to manufacture a meandering conductive trace formed into a meandering arbitrary interconnect in shape of a 3D pretzel that is completely embedded in dielectric. The conversion between g code and pgm-code was de...
Article
For the first time, a fully three-dimensional (3D) electric circuit was modeled in a 3D environment and manufactured via an automated hybrid direct-write 3D printing process. The implications and applications of this significant achievement are enormous because it allows circuits to be designed and manufactured in virtually any form factor. To acco...
Conference Paper
Full-text available
patially-variant photonic crystals (SVPCs) are a new concept in photonics that provide new optical properties and an extraordinary means for multiplexing functions and incorporating bio-inspired randomness and materials. In the present work, planar SVPCs based on self-collimation are investigated.
Article
In this paper, we develop processes for printing 3-D structures by microdispensing materials loaded with dielectric and magnetic powders. Manufacturing with these materials is demonstrated by 3-D printing simple tower and bridge structures. The dielectric and magnetic properties are adjusted by loading different amounts of powder into a host silico...
Article
This paper presents the fabrication, modeling, and testing of a metamaterial based passive wireless temperature sensor consisting of an array of closed ring resonators (CRRs) embedded in a dielectric material matrix. A mixture of 70 vol% Boron Nitride (BN) and 30 vol% Barium Titanate (BTO) is used as the dielectric matrix and copper washers are use...
Conference Paper
Optical components exploiting Pancharatnam-Berry phase are implemented by harnessing laser induced stress birefringence. Beam converters for obtaining beams with orbital angular momentum are demonstrated in glass and crystalline materials using this technique.
Article
Full-text available
Digital manufacturing, or 3D printing, is a rapidly emerging technology which enables novel designs that incorporate complex geometries and even multiple materials. In electromagnetics and circuits, 3D printing allows the dielectrics to take on new and profound functionality. This paper introduces negative uniaxial metamaterials (NUMs) which are bi...
Article
Full-text available
In this work we report an ultra-thin all-dielectric antenna that was designed, built, tested, and compared with simulated data. The objective of this research was to develop an antenna that is easily manufactured by common 3D printers available today. 3D printing is quickly revolutionizing manufacturing and the need to incorporate electrical elemen...
Article
Full-text available
A fast and simple design methodology for transformation optics (TO) is described for devices having completely arbitrary geometries. An intuitive approach to the design of arbitrary devices is presented which enables possibilities not available through analytical coordinate transformations. Laplace's equation is solved using the finite-difference m...
Conference Paper
Full-text available
This work reports the fabrication of micron-scale spatially variant photonic crystals (SVPCs) and their use for steering light beams through turns with bending radius Rbend on the order of ten times the optical wavelength λ0. Devices based on conventional photonic crystals, metamaterials, plasmonics and transformation optics have all been explored...
Article
Spatial transforms are a popular technique for designing periodic structures that are macroscopically inhomogeneous. The structures are often required to be anisotropic, provide a magnetic response, and to have extreme values for the constitutive parameters in Maxwell's equations. Metamaterials and photonic crystals are capable of providing these,...
Chapter
This chapter introduces the tools and methodologies that can be used to engineer the dispersion and anisotropy of periodic electromagnetic structures. The theory and concepts are presented in language that is as simple as possible, so the information will be useful and interesting to a wide audience. The history and motivation for the topic is give...
Article
Full-text available
New metal/polymer composite filaments for fused deposition modeling (FDM) processes were developed in order to observe the thermo-mechanical properties of the new filaments. The acrylonitrile butadiene styrene (ABS) thermoplastic was mixed with copper and iron particles. The percent loading of the metal powder was varied to confirm the effects of m...
Article
A spatially-variant photonic crystal (SVPC) that can control the spatial propagation of electromagnetic waves in three dimensions with high polarization sensitivity was fabricated and characterized. The geometric attributes of the SVPC lattice were spatially varied to make use of the directional phenomena of self-collimation to tightly bend an ungu...
Article
Full-text available
In this paper an all-dielectric frequency selective surface (ADFSS) was developed using genetic algorithms and fast Fourier transforms to generate random geometries. This device showed a stop-band fractional bandwidth of 54% and a field-of-view of 16°. The optimized FSS was manufactured by 3D printing and the frequency response was measured in the...
Conference Paper
Full-text available
Spatially-variant photonic crystals can be used to direct light through tight turns, with turning radii as small as R bend ~ 20 µm, whereas waveguides having similar R bend exhibit high loss.
Article
Full-text available
The finite-difference frequency-domain (FDFD) method is a very simple and powerful approach for rigorous analysis of electromagnetic structures. It may be the simplest of all methods to implement and is excellent for field visualization and for developing new ways to model devices. This paper describes a simple method for incorporating anisotropic...
Article
In this work, an all-dielectric frequency selective surface was developed for high power microwaves. By avoiding the use of metals, arcing at field concentration points and heating in the conductors was avoided. To do this in a compact form factor while still producing a strong frequency response, we based our design on guided-mode resonance (GMR)....
Article
Full-text available
Spatially-variant photonic crystals (SVPCs), in which the orientation of the unit cell changes as a function of position, are shown to be capable of abruptly controlling light beams using just low index materials and can be made to have high polarization selectivity. Multi-photon direct laser writing in the photo-polymer SU-8 was used to fabricate...
Article
Full-text available
Wireless passive temperature sensors are gaining increasing attention due to the ever-growing need of precise monitoring of temperature in high temperature energy conversion systems such as gas turbines and coal-based power plants. Unfortunately, the harsh environment such as high temperature and corrosive atmosphere present in these systems limits...
Article
Full-text available
Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, EMI immunity, high sensitivity, and multiple multiplexing schemes, as compared to conventional electricity based strain sensors. FBG sensors written in Polarization Maintaining (PM) optical fiber offer an add...
Article
Wireless passive temperature sensors have been receiving increasing attention due to the ever-growing need of higher energy efficiency and precise monitoring of temperatures in high temperature energy conversion systems such as gas turbines and coal-based power plants. Unfortunately, the harsh environment such as high temperature and corrosive atmo...
Conference Paper
Tight control of an optical beam is demonstrated based on self-collimation within three-dimensional all-dielectric photonic crystals for which the orientation of the unit cell is progressively varied to direct power flow.
Article
Full-text available
3-D printing allows increased design flexibility in the fabrication of microwave circuits and devices and is reaching a level of maturity that allows for functional parts. Little is known about the RF and microwave properties of the standard materials that have been developed for 3-D printing. This paper measures a wide variety of materials over a...
Conference Paper
The paper introduces optical nano-hair structures made from high-κ dielectrics that can be used to impart an arbitrary phase function to the transmitted beam. The concept behind the design of these new structures is elaborated.
Article
Full-text available
We present a method for fabricating high aspect ratio metal-oxide, sub-wavelength grating structures. These "nano-hair" structures are composed of alumina cylindrical pillars, partially embedded in a supporting fused silica substrate. The fabricated nano-hair structures demonstrate phase control of the transmitted beam while maintaining a peak tran...
Article
Full-text available
Self-collimation in photonic crystals has received a lot of attention in the literature, partly due to recent interest in silicon photonics, yet no performance metrics have been proposed. This paper proposes a figure of merit (FOM) for self-collimation and outlines a methodical approach for calculating it. Performance metrics include bandwidth, ang...
Article
Full-text available
The printed circuit board is the backbone of electronics and a large number of consumer devices. The challenge to put more function