Parviz Zolfaghari

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.

We developed a microelectromechanical system for simultaneous temperature and pressure measurements, which is integrated on a fiber. The developed platform is integrated at the tip of a fiber optic cable for surgical assistance. The platform comprises a three-layer sealed micrometer-scale membrane that deflects in response to external pressure. Moreover, we exploit the change in bandgap wavelength of the Gallium Arsenide substrate to monitor temperature. The developed multi-sensor is capable of point-wise and decoupled measurements, owing to its compact form factor and different physical principles used for sensing of temperature and pressure. Both sensors are interrogated using a multimode fiber that is butt-coupled to the substrate, allowing for simple integration and alignment as opposed to a singlemode fiber. Furthermore, the exploitation of graded-index in the fiber core enables measurement immunity to fiber bending. Experiments were conducted in a pressure chamber and on ex vivo tissue. We measured sensitivities of 9.04 nm/mmHg in displacement for pressure and –1.38% /°C in optical power for temperature. With further development, the proposed device can be adapted to a clinical setting as a assistive tool during ablative medical operations, in determining ablation boundaries while monitoring intravascular or organ pressure as a vital signal.

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.

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 × 1.4 mm oval mirror within a 7 × 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 Vp-p periodic pulse driving. The system achieves optical scan angles of 4.8° and 11.5° 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·mm·kHz (vertical) and 623 deg·mm·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.

Objective: This paper discusses analytically and by simulation, a novel disk and ring-shaped piezoelectric micromechanical acoustic resonators in which asymmetric Lamb wave mode is induced in a thin-film aluminum nitride (AlN)-on-silicon structure. Method: The piezoelectric resonators are designed and simulated at two-port state by the aid of FEM tool. An analytical investigation is carried out in order to study the propagation of asymmetric lamb wave in a cylinder structure. Circular electrodes are utilized for excitation of intended order of asymmetric acoustic Lamb wave in the structures. Due to the significance of feedthrough capacitances in the piezoelectric MEMS resonators in high-frequency applications, these capacitances are calculated and extracted. Several electrodes and tethers configurations are introduced and simulated by FEM simulation in order to study distortion of resonator structures. Result: Stress-free nodal zones close to the resonators outer edge are identified and support tethers, which are used to anchor the resonators, are connected to those points by applying the notch method. Connecting anchoring tethers to stress-free nodal zones considerable decreased tether deformation leading to lower loss for resonators. The prototype models of structures work at 307 MHz and 318 MHz for the disk-shaped and ring-shaped resonators, respectively. Numerous transient and harmonic analysis have been carried out in order to study resonators behavior at the fundamental mode and their spurious electrical response. Conclusion: The proposed structures in this paper can be a promising choice for different applications ranging from RF filter, RF oscillators, RF micromachined circuits and physical and biochemical sensors.

This paper reports on a new structure for Aluminum Nitride (AlN) thin film lamb wave resonators. Electrodes are structured into different forms to study wave propagation in structures with different electrodes configuration. For this purpose, several electrode configuration is introduced and simulation results for them is presented. Simulation results are presented in the paper and also a discussion about wave propagation.