About

M. Hassan Arbab is an Associate Professor specializing in terahertz emission, detection, and imaging technologies and their applications in biophotonics. His research focuses on developing advanced imaging techniques and technologies that leverage terahertz radiation for biomedical applications. His work aims to enhance the capabilities of biophotonics through innovative imaging solutions, contributing to the fields of biomedical engineering and optical imaging.

Research topics

• Optics
• Materials science
• Physics
• Computer science
• Biomedical engineering

Selected publications

• Fast terahertz corneal imaging system with automatic motion compensation: application to in vivo mapping of hydration gradients

  2026-03-05

  articleSenior author

  Terahertz time-domain spectroscopy (THz-TDS) has shown strong potential for noncontact corneal hydration sensing and surface-profile metrology, but in vivo imaging remains challenging because the curved corneal surface requires precise phase matching and rapid acquisition to suppress motion artifacts. We report a fast single-pixel THz corneal imaging system that combines electronically controlled optical sampling (ECOPS) for kilohertz waveform acquisition with a direct - drive two-axis beam-steering mirror and a pair of custom hyperbolic-elliptical lenses optimized for wide-field spherical scanning. The system acquires a 40°×40° field of view in 0.8 s (and 60°×60° in <3 s), enabling sub -second spectral imaging while maintaining the required wavefront curvature. To compensate for subject motion, we introduce an automatic alignment method that estimates lateral and axial misalignment from the time-of-arrival surface profile and repositions the scanner using three motorized translation axes. As a demonstration, we captured time-lapse THz images of a contact-lens corneal phantom during controlled drying and observed reproducible changes in the reflected waveform amplitude and shape consistent with the measured decrease in hydration. These results establish a practic al route toward in vivo THz mapping of corneal hydration gradients with automated motion compensation.

  PublisherDOI

• On the impact of imperfect polarizers for the calibration of polarimetric terahertz systems

  2026-03-05

  articleSenior author
  PublisherDOI

• Characterization of in vivo frostbite injury depth using a portable handheld terahertz spectroscopic scanner

  2026-03-05

  articleSenior author

  Tissue damage from frostbite injury may not be apparent until several weeks post-injury; however, early assessment of injury depth is critical for guiding clinical treatment. Recently, we have demonstrated that terahertz (THz) spectroscopic imaging can determine the severity and predict healing outcome of thermal burns with high accuracy. In this work, we extend this work to frostbite and present THz images captured from an in vivo porcine frostbite model using our Portable HAndheld Spectral Reflection (PHASR) Scanner. We establish a standardized frostbite injury model using controlled liquid nitrogen exposure, as confirmed by histological assessments. We then analyze the THz spectra within 24 and 72 hours after frostbite induction and observe a significant difference (p<0.05) between partial- and full-thickness frostbite injuries, as well as healthy tissue using a physical double-Debye dielectric relaxation model. Finally, we employ a support vector machine for classification and demonstrate an area under the receiver operating curve of 0.94, 0.85, and 0.87 for healthy tissue, partial-, and full-thickness frostbite injuries, respectively. This work suggests the potential of THz time-domain spectroscopy for early, noninvasive assessment of frostbite depth.

  PublisherDOI

• Terahertz spectral imaging for early assessment of frostbite injuries using the double Debye model and supervised machine learning

  Biomedical Optics Express · 2026-03-05

  articleOpen accessSenior author

  Early assessment of the severity of frostbite injuries is critical for guiding clinical management and improving patient outcomes; however, tissue damage evolves dynamically and is difficult to predict during the acute phase. Terahertz time-domain spectroscopy (THz-TDS) has previously demonstrated high accuracy in the early triage of thermal burn injuries. In this study, we evaluate the potential of the THz-TDS modality using a portable handheld scanner to assess the depth of frostbite wounds. A standardized in vivo porcine frostbite model was employed, and injury classification was performed using a support vector machine algorithm. We demonstrate that the area under the receiver operating characteristic (ROC) curves was 0.94, 0.85, and 0.87 for healthy tissue, partial-thickness frostbite, and full-thickness injuries. In addition, we explored the use of the double Debye dielectric relaxation model of tissue to reduce the data dimensionality. We observed significant statistical differences between the double Debye parameters of the three groups. These results demonstrate the potential of THz-TDS imaging for early, non-destructive assessment of the depth of frostbite injuries and suggest its potential utility in improving clinical decision-making and surgical outcomes.

  PublisherDOI

• Terahertz Spectral Imaging for the Assessment of Frostbite Injuries Using the Double Debye Model and Supervised Machine Learning

  Research Square · 2026-02-20

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• In situ calibration of terahertz time-domain polarimetry systems with a leaky wire grid polarizer

  Research Square · 2026-01-06

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• 514 Physics-based Deep Learning Models for Accurate Triage of Burn Wounds Using a Terahertz Spectral Scanner

  Journal of Burn Care & Research · 2025-03-01

  articleOpen access1st authorCorresponding

  Abstract Introduction The formation of edema and the dynamic nature of the zone of stasis, surrounding the zone of coagulation, of a burn are mainly responsible for inaccuracies in burn delineation. Today, burn triage is still based on visual and tactile inspection by experienced surgeons, while histology remains the gold standard, albeit invasive and time-consuming. The complexity of the dynamic molecular and cellular level changes, which skin constituents experience post burn, gives rise to most of the discrepancies in burn assessment. Early and highly accurate differentiation of burn wounds can alter the treatment course, reduce length of hospital stay and improve overall recovery of the patients. Terahertz spectroscopy is a promising new technology that can differentiate between burn wounds by quantifying the bound and free water content of the tissue as well as the scattering by deep dermal structures. Methods Recently, physics-based deep learning models to predict the healing outcomes of porcine burns have exploited the rich terahertz spectral data to achieve highly accurate classification on Day 1 after injury. Using a Support Vector Machine and Deep Neural Networks an accuracy between 90 to 94.7% was achieved to predict if the burn would re-epithelialize spontaneously within 28 days. In this presentation, we explore the utility of the same AI models and the terahertz handheld scanner in the first pilot human study of this technology. We monitored the healing outcome of patients (n = 20 burns) admitted within 48 hours of the initial injury. If the attending physician determined that surgical intervention was necessary, we obtained histological biopsies from the excised tissue to determine the depth of the burn (control experiment). However, if the burn was determined to be superficial partial thickness, we monitored the re-epithelialization rate weekly (on days 7, 14, 21, and 28) to determine the wound closure date, which serves as the ground truth for the machine learning algorithm. As shown in the attached figure, in five-fold cross-validation, a model is first trained over the training set (80% of spectral data), and the remaining 20% is reserved for calculating the classification error. We calculate the sensitivity, specificity, and accuracy rates, using receiver operating characteristic (ROC) analysis. Results Preliminary results from this ongoing pilot clinical study indicate that the terahertz spectroscopy can achieve similarly high accuracy results (>90%) in predicting the healing outcome of burn wounds. Conclusions This presentation will report on the first use of the terahertz spectral imaging modality in a pilot human study. Our preliminary results indicate that terahertz spectroscopy can achieve high accuracy in differentiating burn wounds on Day 1 post-injury and predict the ultimate healing outcome. Applicability of Research to Practice An accurate and precise method of burn depth classification is essential for making appropriate burn treatment decisions. Funding for the Study U.S. Army Medical Research Acquisition Activity (USAMRAA) through the Military Burn Research Program (MBRP) and the National Institute of General Medical Sciences (NIGMS) of the National Institutes of Health.

  PublisherOA PDFDOI

• Video-rate terahertz spectral imaging of spherical surfaces

  2025-03-19

  articleSenior author
  PublisherDOI

• In-Situ Polarimetric Calibration of Broadband Terahertz Imaging Systems with and Uncharacterized Imperfect Wire Grid Polarizer

  2025-08-17

  articleSenior author

  With the recent advances in terahertz time-domain instruments, the design of handheld scanners has drawn significant attention. Recently, we developed a polarimetric version of our Portable HAndheld Spectral Reflection (PHASR) Scanner and introduced the in-situ calibration of the scanner using a rotating wire grid polarizer. However, the wire grid polarizers are far from ideal, due to their leaky spectral performance. In this work, we propose a new approach to simultaneously characterize both the scanner, and the imperfect wire grid polarizer used for calibration measurements to improve the characterization of the handheld device. In addition, the effect of the choice of rotation angles of the polarizer will be discussed using matrix condition number minimization analysis.

  PublisherDOI

• High-speed spectroscopic imaging of corneas using compressed sensing in a single-pixel detector and spherical phase front matching

  2025-08-17

  articleSenior author

  Curved biological surfaces such as the cornea, joins, and nose present a challenging imaging target for terahertz spectroscopy due to the difficulty collecting the reflected light. Additionally, the need to scan the THz beam point-by-point results in slow scans which are susceptible to motion artifacts, for instance, due to breathing. Here, we present a video-rate terahertz imaging system for imaging curved surfaces. We show how our recent techniques for scanning spherical surfaces can be combined with THz single-pixel imaging to produce a compressed sensing imaging system for spherical targets. This imaging system will use high-speed ECOPS terahertz trace acquisition to form video-rate images and can pave the way for clinical translation of THz technology for ophthalmological applications.

  PublisherDOI

Recent grants

• Noninvasive Broadband Terahertz Assessment of Burn Severity

  NIH · $2.6M · 2015–2023

Frequent coauthors

• Zachery B. Harris

  Stony Brook University

  75 shared

• Mahmoud E. Khani

  44 shared

• Omar B. Osman

  Cleveland Clinic

  38 shared

• Kuangyi Xu

  36 shared

• Juin W. Zhou

  32 shared

• Adam J. Singer

  Stony Brook School

  28 shared

• Arjun Virk

  Stony Brook University

  20 shared

• Andrew Chen

  Chinese Academy of Medical Sciences & Peking Union Medical College

  17 shared