About

Steve Blair is a Professor in the Department of Electrical and Computer Engineering at the University of Utah. His research focuses on optics and photonics, specifically the physics and applications of resonance phenomena, including linear and nonlinear optical phenomena. His work encompasses resonance enhancement in fluorescence-based molecular transduction, the kinetics of bi-molecular interactions, the development of microfabricated optical biosensor array systems, and the design of periodic and aperiodic systems of artificial resonators. Additionally, he investigates plasmonics and nanophotonic systems based on metallic structures, contributing to advancements in optical sensing and photonic device engineering.

Research topics

• Condensed matter physics
• Physics
• Materials science
• Optics
• Optoelectronics
• Molecular physics

Selected publications

• Holographic Mapping of Orbital Angular Momentum using a Terahertz Diffractive Optical Neural Network

  Advanced Intelligent Discovery · 2026-04-02 · 1 citations

  articleOpen access

  Using orbital angular momentum (OAM) in the terahertz (THz) range provides a new degree of freedom for communication and imaging systems. This study presents a compact diffractive optical neural network (DONN) designed to recognize discrete and superposed OAM states at THz frequencies. The network consists of six diffractive layers trained to spatially separate nine OAM modes with topological charges from 1 to 9. Each mode is projected to a distinct position on the output plane, enabling direct recognition of its state. The structure was fabricated through low‐cost 3D printing techniques with high‐impact polystyrene, allowing for scalable and practical implementations. Experimental validation at 0.3 THz demonstrates good fidelity of mode discrimination and mapping. The proposed approach offers a robust and economical pathway for OAM decoding, offering new opportunities for beam manipulation through THz systems based on DONNs.

  PublisherDOI

• Cortical Response to Acute Implantation of the Utah Optrode Array in Macaque Cortex (Adv. Healthcare Mater. 3/2026)

  Advanced Healthcare Materials · 2026-01-01

  article
  PublisherDOI

• Binary phase-only gallium oxide diffractive optical element for beam shaping

  Scientific Reports · 2025-02-11 · 4 citations

  articleOpen access

  This study presents an experimentally validated demonstration of an inverse-optimized binary phase-only gallium oxide diffractive optical element (DOE). This DOE transforms an incident Gaussian beam into a square flat-top beam at the working plane. The design methodology for this binary phase-only DOE beam shaper is founded on an efficient process that integrates the modified Gerchberg-Saxton algorithm and the adjoint method. Experimental characterization of the fabricated device on a single crystal [Formula: see text]gallium oxide substrate is conducted at a wavelength of 532 nm, confirming its ability to transform an incident Gaussian beam into a focused square flat-top beam. Such a device holds significant promise for various high-power laser applications, notably in laser welding and similar domains. Furthermore, because of the ultrawide bandgap of gallium oxide, DOEs operating at shorter wavelengths in the UV are also possible based on this technique.

  PublisherOA PDFDOI

• Low‐Loss Parowax‐Imprinted Diffractive Neural Network for Orbital Angular Momentum Terahertz Holographic Imaging

  Advanced Photonics Research · 2025-03-06 · 9 citations

  articleOpen access

  The helical phase front of orbital angular momentum (OAM) waves offer additional multiplexing degree‐of‐freedom to increase the capacity of communication systems in the terahertz domain, which in turn can significantly benefit forthcoming high‐speed wireless sixth‐generation communication networks. This work introduces a diffractive neural network approach for recognizing the topological charge of OAM waves and their superposition. Moreover, it is shown that the diffractive network can further enable mathematical operations through the topological charges (TCs) of the superposed OAM waves. The diffractive neural networks (DNN) are fabricated through an imprinting technique with low‐loss parowax material. To validate the feasibility of this general approach, experimental demonstrations are conducted, which show that the low‐loss parowax DNN effectively detects the TCs of the OAM waves and display them in a numerical format.

  PublisherOA PDFDOI

• Compact bandpass pixelated microwave filters with short-circuited stubs via inverse design

  Scientific Reports · 2025-07-15 · 1 citations

  articleOpen access

  Pixelated RF metasurfaces are poised to revolutionize electromagnetic component design by enabling compact, versatile, high-performance solutions. Building upon our prior work in random metasurface-based filters and inverse design methods, we propose pixelated notch filters by integrating shorted stubs within a top ground plane. Using a combination of established optimization techniques, including direct binary search optimization, genetic algorithms, and a randomization mutation algorithm, we synthesize filters enhanced by parallel short-ended feed schemes, which are shown to improve stopband response. Design iterations are automated via Python scripting, commercial full-wave simulations, and Visual Basic within the electromagnetic solver, overcoming initial seeding challenges and enabling innovative pattern-generation techniques. For implementation, laser ablation is employed to precisely remove copper on PCBs, streamlining fabrication on Rogers Kappa 438 substrates. Preliminary results demonstrate the ability of the approach to reach target insertion loss levels with compact geometries, advancing pixelated metasurface-based filter design with enhanced tunability and overall performance.

  PublisherOA PDFDOI

• The Utah Optrode Array for large volume optogenetic manipulation in the non-human primate brain

  2025-03-19

  articleSenior author

  Optogenetics studies in non-human primates (NHPs) are crucial for understanding neural circuit function and dysfunction in human brain disorders. NHP optogenetics has been hampered by the lack of devices for light delivery to deep neural tissue across large areas. We developed the Utah Optrode Array (UOA), a 10x10 array of penetrating glass light-guides, tiling a 4x4mm2 area, bonded to interleaved 10x10 needle-aligned and 9x9 interstitial µLED arrays, for independent photostimulation of deep and superficial brain tissue. Extensive bench and in vivo testing in macaque primary visual cortex demonstrated that the UOA allows for spatiotemporally patterned photostimulation of deep cortical layers with sub-millimeter resolution, at the scale of single cortical layers and columns, over a large volume. This selectivity can be scaled up to multiple layers and columns by varying the number of simultaneously activated μLEDs and/or the light irradiance, allowing for high experimental flexibility. The UOA will improve our understanding of neural circuit function in NHPs, and the circuit-level basis of human brain disorders, and offers great potential for clinical applications.

  PublisherDOI

• Cortical Response to Acute Implantation of the Utah Optrode Array in Macaque Cortex

  Advanced Healthcare Materials · 2025-09-15

  articleOpen accessCorresponding

  Abstract Optogenetics has transformed neural circuit studies, but its application to large‐brained species like non‐human primates (NHPs) remains limited. A major challenge in NHP optogenetics is delivering light to large volumes of deep neural tissue with high spatiotemporal precision, without affecting superficial tissue. To overcome these limitations, we recently developed and tested in vivo in NHP cortex, the Utah Optrode Array (UOA). This is a 10 × 10 array of penetrating glass shanks, tiling a 4 × 4 mm 2 area, bonded to interleaved needle‐aligned and interstitial µLED arrays, enabling independent photostimulation of deep and superficial tissue. Here, the acute biological response to UOA implantation in NHP cortex is investigated, to optimize device design for reduced insertion trauma and chronic response. To this goal, UOA shank diameter, geometry, and insertion pressure are varied, and their effects on astrocytes, microglia, and neuronal viability are assessed, following acute implantation. It is found that UOAs with smaller shank diameter, smooth surface texture, and round tips cause the least damage. Higher insertion pressures have limited effects on inflammation, but cause greater tissue compression. The results highlight the importance of balancing shank diameter, geometry, and insertion pressure in UOA design for preserving tissue integrity and improving long‐term UOA performance and biocompatibility.

  PublisherOA PDFDOI

• Silicon Photonic Test-Point Selection by Integrating Design Parameters with Hypergraph Partitioning

  2025-09-20

  articleSenior author

  As silicon photonic integrated circuits (PICs) increase in complexity, ensuring their reliability against manufacturing and operational variations necessitates robust Design-for-Test (DfT) strategies. We present an adaptable methodology for DfT insertion in large-scale PICs, centered on physics-informed hypergraph partitioning. Our approach uniquely leverages hypergraph-based weighting derived from process sensitivities (e.g. etch, doping) and operational drifts (e.g. thermal, injection), quantified using partial derivatives from foundry data or Transfer Matrix Method (TMM) simulations. This assigns actionable risk values to both devices (nodes) and interconnects (hyperedges). We employ k-way partitioning to achieve finer sub-network isolation and targeted test access, crucial for vulnerability localization in complex PICs like multi-level ring resonator networks or large MZI-based crossbars. Experiments performed on PIC designs demonstrate the application of the proposed risk coverage metric to vulnerability localization and test point insertion, achieved with quantifiable and moderate overhead.

  PublisherDOI

• Control of Extraordinary Optical Transmission in Resonant Terahertz Gratings via Lateral Depletion in an AlGaN-GaN Heterostructure

  ArXiv.org · 2025-11-12

  preprintOpen access

  Periodic metallic gratings on substrates can support a range of electromagnetic modes, such as leaky waveguide, guided-resonant, and Fabry-Perot (FP) cavity modes, which can strongly modulate optical transmission under resonant excitation. Here, we investigate how this coupling can be dynamically manipulated through charge-density control in a laterally patterned AlGaN/GaN heterostructure. The structure comprises metallic stripes separated by regions containing a two-dimensional electron gas (2DEG), forming a periodically modulated interface whose electromagnetic response is governed by the charge density between the stripes. In the unbiased state, the conductive 2DEG screens the incident terahertz field and suppresses excitation of guided modes. When the 2DEG is depleted, the change in boundary conditions allows efficient coupling into substrate resonances, producing a strong modulation at particular frequencies where extraordinary optical transmission (EOT) through the structure takes place. The results highlight the sensitive dependence of guided-mode-resonance (GMR) mediated EOT on inter-stripe charge distribution and demonstrate a direct interplay between carrier dynamics and resonant electromagnetic phenomena in the terahertz regime.

  PublisherOA PDFDOI

• Optogenetic approaches for circuit dissection in the non-human primate

  2025-03-19

  articleSenior author

  Optogenetics has transformed the study of neural circuit function, but its application to non-human primates (NHPs) remains challenging. Two major challenges to applying optogenetics to NHPs have been the lack of viral tools to restrict opsin expression to specific cell types, and the lack of devices for light delivery to deep neural tissue across large brain volumes. To overcome the first challenge, we have validated and characterized in NHP cortex several recently developed viral vectors designed to restrict transgene expression to specific cell types. To overcome the second challenge, we have developed the Utah Optrode Array (UOA), a 10x10 array (tiling 4x4 mm area) of penetrating glass needles. An electrically addressable μLED array independently delivering 450nm light through each needle, is integrated to the device. A second 9x9 µLED array is interleaved on the same device for independent surface stimulation. In vivo testing in macaque primary visual cortex demonstrates that the UOA allows for spatiotemporally patterned photostimulation of deep cortical layers with sub-millimeter resolution over a large volume. This selectivity can be scaled up to multiple layers and columns

  PublisherDOI

Recent grants

• Optrode array for optical neural stimulation and recording

  NSF · $180k · 2013–2017

• CAREER: Integrated-Optic Nanoparticle Biosensor Arrays

  NSF · $437k · 2002–2008

• Novel optical properties of metallic nanocavities

  NSF · $276k · 2006–2010

• Development of an integrated array for simultaneous optogenetic stimulation and electrical recording to study cortical circuit function in the non-human primate brain

  NIH · $2.4M · 2016–2021

• NIH Grant R21EB000481

  NIH · $207k · 2004

Frequent coauthors

• Priyank Kalla

  University of Utah

  48 shared

• Christopher Condrat

  44 shared

• Mohammad Almalkawi

  Skyworks Solutions (United States)

  36 shared

• Chengcheng Yao

  36 shared

• Khair Al Shamaileh

  Purdue University Northwest

  36 shared

• Hoi Lee

  The University of Texas at Dallas

  36 shared

• Chun‐Jen Su

  36 shared

• Chung-Chih Hung

  National Yang Ming Chiao Tung University

  36 shared

Labs

• Utah Nanofab Utah Robotics Center U-Smart Energy LaboratoryPI