arXiv subjects

Parviz Zolfaghari

Publications and source records attributed to Parviz Zolfaghari.

3 recordsLinked to original sources

arXiv2025

Optical design and characterization of a multi-depth vision simulator

We present a vision simulator device (Katsim), a compact near-eye optical display designed for assessing postoperative corrected vision, preoperative intraocular lens (IOL) assessment, and objective IOL characterization. The system forms a virtual image using an amplitude-modulated LCoS spatial light modulator (AM-SLM), RGB LED illumination, and a high-speed varifocal lens. In the proposed architecture, the LED illumination and varifocal lens diopter changes are triggered in synchrony with the SLM RGB subframes, rendering three depth planes perceptually simultaneously via high-frequency time-multiplexing. Operating at 60 frames per second (fps), the system achieves an effective 180 Hz depth-coded cycle, enabling sharp, multi-depth rendering within a dynamically adjustable depth range from 0.2 m to optical infinity. The system's eyebox is configurable from 1 to 5 mm, while maintaining a fixed spatial location and preserving angular magnification regardless of changes in focus or eyebox size. The designed system features a 9.15-degree field of view. An integrated infrared pupil-tracking module detects non-cataractous regions of the cataractous crystalline lens, and the projected imagery is mechanically steered through those clear zones in real time. The proposed vision simulator supports both subjective simulation of post-surgical vision for patient-specific counseling and objective optical evaluation of IOLs, including resolution and contrast fidelity (e.g., modulation transfer function, contrast transfer function, and defocus curves). By decoupling depth modulation from eyebox position and size, the system offers a modular, portable platform that supports enhanced preoperative planning, personalized IOL selection, objective IOL characterization, and use as a novel research vision tool.

physics.optics↗

arXiv2025

A Multifunctional Capacitive Sensing Platform for Wireless Vascular and Heart Monitoring

We present a multifunctional, antenna-integrated capacitive sensing (MAiCaS) platform for passive, wireless, and real-time cardiovascular monitoring. Unlike conventional systems that require separate sensors and wireless modules, our device unifies sensing, telemetry, and mechanical functionality into a compact and scalable design by exploiting the parasitic capacitance of an inductive antenna as a strain-sensitive element. The sensor is fabricated using a cleanroom-free, single-step UV laser patterning process on a flexible PDMS substrate, reducing manufacturing complexity and enabling high reproducibility. The MAiCaS is suitable for three different applications: as a sensor for epicardial strain measurement, a stent as a sensor, and a vascular graft sensor. We demonstrate MAiCaS's versatility by validating its wireless resonance-based response to strain, pressure, and deformation across unrolled and rolled forms. In vitro experiments demonstrated consistent resonance frequency shifts under physiological conditions, with stable performance on skin, in PBS, human serum, and simulated vascular environments. Repeatability and aging tests confirmed its long-term reliability and elasticity under cyclic loading. Calibration curves revealed high sensitivity across all configurations, with wireless interrogation achieved through S11 parameter measurements and resonance frequency shift as the output metric. The sensitivity of the device was measured to be 2.9 MHz per 1% strain, 0.43 MHz/mmHg, and 309.6kHz/\textmu m for epicardial patch, graft, and stent integrated sensor, respectively. The operation of MAiCaS was evaluated in a human experiment. This monolithic sensor architecture provides a scalable and cost-effective solution for battery-free monitoring of vascular dynamics, with potential for remote diagnostics, post-surgical follow-up, and continuous cardiovascular health management.

eess.SY↗

arXiv2025

2D PZT MEMS Resonant Scanner Using a Three-Mask Process

This work presents the design, simulation, fabrication, and characterization of a novel architectural compact two-dimensional (2D) resonant MEMS scanning mirror actuated by thin-film lead zirconate titanate (PZT). The device employs an innovative mechanically coupled dual-axis architecture fabricated using a three-mask process on an SOI-PZT deposited wafer, significantly reducing system complexity while achieving high performance. The scanner integrates a 1 $\times$ 1.4 mm oval mirror within a 7 $\times$ 4.7 mm die, actuated by PZT thin-film elements optimized for resonant operation at 3.6 kHz (vertical) and 54.2 kHz (horizontal) under 12 V$_{\mathrm{p-p}}$ periodic pulse driving. The system achieves optical scan angles of 4.8$^\circ$ and 11.5$^\circ$ in vertical and horizontal directions, respectively, with quality factors of 750 (vertical) and 1050 (horizontal). These values contribute to high scanning bandwidth-efficiency products of 24.2 deg$\cdot$mm$\cdot$kHz (vertical) and 623 deg$\cdot$mm$\cdot$kHz (horizontal), among the higher values reported for 2D PZT-MEMS scanners. Finite element analysis confirmed minimal stress and mirror deformation, and experimental validation demonstrated excellent agreement with simulation results. This architecture demonstrates the feasibility of high-resolution laser scanning, as required in applications such as OCT, LiDAR, and displays, by achieving performance levels in line with those used in such systems.

eess.SY↗