Asaf Ilovitsh received his B.Sc. in Physics (2004), M.Sc. in Electrical Engineering (2012), and Ph.D. in Electrical Engineering (2016), from Bar Ilan University, Israel. His Ph.D. research involved developing new methods for super resolution optical imaging, especially using the time domain. Asaf joined the Ferrara lab in 2016 as a postdoctoral fellow. His research involves developing rapid elastography measurements using MR-guided Focused Ultrasound (MRgFUS), and developing new ultrasound imaging methods.

Professional Education

  • Doctor of Philosophy, Bar-Ilan University (2017)
  • Master of Science, Bar-Ilan University (2013)
  • Bachelor of Science, Bar-Ilan University (2005)

Stanford Advisors


All Publications

  • Simultaneous Axial Multifocal Imaging Using a Single Acoustical Transmission: A Practical Implementation IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL Ilovitsh, A., Ilovitsh, T., Foiret, J., Stephens, D. N., Ferrara, K. W. 2019; 66 (2): 273–84


    Standard ultrasound imaging techniques rely on sweeping a focused beam across a field of view; however, outside the transmission focal depth, image resolution and contrast are degraded. High-quality deep tissue in vivo imaging requires focusing the emitted field at multiple depths, yielding high-resolution and high-contrast ultrasound images but at the expense of a loss in frame rate. Recent developments in ultrasound technologies have led to user-programmable systems, which enable real-time dynamic control over the phase and apodization of each individual element in the imaging array. In this paper, we present a practical implementation of a method to achieve simultaneous axial multifoci using a single acoustical transmission. Our practical approach relies on the superposition of axial multifoci waveforms in a single transmission. The delay in transmission between different elements is set such that pulses constructively interfere at multiple focal depths. The proposed method achieves lateral resolution similar to successive focusing, but with an enhanced frame rate. The proposed method uses standard dynamic receive beamforming, identical to two-way focusing, and does not require additional postprocessing. Thus, the method can be implemented in real time on programmable ultrasound systems that allow different excitation signals for each element. The proposed method is described analytically and validated by laboratory experiments in phantoms and ex vivo biological samples.

    View details for DOI 10.1109/TUFFC.2018.2885080

    View details for Web of Science ID 000458775800003

    View details for PubMedID 30530361

    View details for PubMedCentralID PMC6375789

  • Acoustic radiation force imaging using a single-shot spiral readout. Physics in medicine and biology Ilovitsh, A., Fite, B. Z., Ilovitsh, T., Ferrara, K. W. 2019


    The purpose of this study is to develop and validate rapid magnetic resonance acoustic radiation force imaging (MR-ARFI) using a single shot spiral readout for focused ultrasound (FUS) guidance and for local tissue displacement measurements. A magnetic resonance guided FUS system was used to focus a 3 MHz ultrasound beam to a predetermined position. MR-ARFI was performed with a Bruker 7T MRI using a modified single-shot spiral readout, with additional motion encoding gradients that convert local displacement into the phase image. Post processing was then used to analyze the resulting displacement and to evaluate the method's performance for the detection of tissue changes resulting from thermal ablation. The single-shot spiral readout acquires a single MR-ARFI image in one second, which is up to two orders of magnitude faster than conventional 2D spin-warp spin echo that acquires the k-space data line by line. The ARFI displacement in tissue mimicking phantoms was detected and localized with less than 5% geometric distortion. The ARFI displacement was also measured pre and post-thermal ablation in an ex-vivo chicken breast. For transmitted peak negative pressure of 8.6 MPa, the maximum displacement of the tissue that was ablated to 70°C was 78% lower than the pre-ablated tissue. Since spiral readout is not prone to geometrical distortion, it is well-suited for FUS guidance, without generating undesired temperature elevation. Additionally, local displacement measurements of tissues can be performed rapidly during thermal ablation procedures and may help to assess the success of the treatment.

    View details for PubMedID 31039549

  • Enhanced microbubble contrast agent oscillation following 250kHz insonation. Scientific reports Ilovitsh, T., Ilovitsh, A., Foiret, J., Caskey, C. F., Kusunose, J., Fite, B. Z., Zhang, H., Mahakian, L. M., Tam, S., Butts-Pauly, K., Qin, S., Ferrara, K. W. 2018; 8 (1): 16347


    Microbubble contrast agents are widely used in ultrasound imaging and therapy, typically with transmission center frequencies in the MHz range. Currently, an ultrasound center frequency near 250kHz is proposed for clinical trials in which ultrasound combined with microbubble contrast agents is applied to open the blood brain barrier, since at this low frequency focusing through the human skull to a predetermined location can be performed with reduced distortion and attenuationcompared to higher frequencies. However, the microbubble vibrational response has not yet been carefully evaluated at this low frequency (an order of magnitude below the resonance frequency of these contrast agents). In the past, it was assumed that encapsulated microbubble expansion is maximized near the resonance frequency and monotonically decreases with decreasing frequency. Our results indicated that microbubble expansion was enhanced for 250kHz transmission as compared with the 1MHz center frequency. Following 250kHz insonation, microbubble expansion increased nonlinearly with increasing ultrasonic pressure, and was accurately predicted by either the modified Rayleigh-Plesset equation for a clean bubble or the Marmottant model of a lipid-shelledmicrobubble. The expansion ratio reached 30-fold with 250kHz at a peak negative pressure of 400kPa, as compared to a measured expansion ratio of 1.6 fold for 1MHz transmission at a similar peak negative pressure. Further, the range of peak negative pressure yielding stable cavitation in vitro was narrow (~100kPa) for the 250kHz transmission frequency. Blood brain barrier opening using in vivo transcranial ultrasound in mice followed the same trend as the in vitro experiments, and the pressure range for safe and effective treatment was 75-150kPa. For pressures above 150kPa, inertial cavitation and hemorrhage occurred. Therefore, we conclude that (1) at this low frequency, and for the large oscillations, lipid-shelled microbubbles can be approximately modeled as clean gas microbubbles and (2) the development of safe and successful protocols for therapeutic delivery to the brain utilizing 250kHz or a similar center frequency requires consideration of the narrow pressure window between stable and inertial cavitation.

    View details for PubMedID 30397280

  • Imaging beyond ultrasonically-impenetrable objects SCIENTIFIC REPORTS Ilovitsh, T., Ilovitsh, A., Foiret, J., Ferrara, K. W. 2018; 8: 5759


    Ultrasound images are severely degraded by the presence of obstacles such as bones and air gaps along the beam path. This paper describes a method for imaging structures that are distal to obstacles that are otherwise impenetrable to ultrasound. The method uses an optically-inspired holographic algorithm to beam-shape the emitted ultrasound field in order to bypass the obstacle and place the beam focus beyond the obstruction. The resulting performance depends on the transducer aperture, the size and position of the obstacle, and the position of the target. Improvement compared to standard ultrasound imaging is significant for obstacles for which the width is larger than one fourth of the transducer aperture and the depth is within a few centimeters of the transducer. For such cases, the improvement in focal intensity at the location of the target reaches 30-fold, and the improvement in peak-to-side-lobe ratio reaches 3-fold. The method can be implemented in conventional ultrasound systems, and the entire process can be performed in real time. This method has applications in the fields of cancer detection, abdominal imaging, imaging of vertebral structure and ultrasound tomography. Here, its effectiveness is demonstrated using wire targets, tissue mimicking phantoms and an ex vivo biological sample.

    View details for PubMedID 29636513

  • Distinct immune signatures in directly treated and distant tumors result from TLR adjuvants and focal ablation THERANOSTICS Chavez, M., Silvestrini, M. T., Ingham, E. S., Fite, B. Z., Mahakian, L. M., Tam, S. M., Ilovitsh, A., Monjazeb, A. M., Murphy, W. J., Hubbard, N. E., Davis, R. R., Tepper, C. G., Borowsky, A. D., Ferrara, K. W. 2018; 8 (13): 3611–28


    Both adjuvants and focal ablation can alter the local innate immune system and trigger a highly effective systemic response. Our goal is to determine the impact of these treatments on directly treated and distant disease and the mechanisms for the enhanced response obtained by combinatorial treatments. Methods: We combined RNA-sequencing, flow cytometry and TCR-sequencing to dissect the impact of immunotherapy and of immunotherapy combined with ablation on local and systemic immune components. Results: With administration of a toll-like receptor agonist agonist (CpG) alone or CpG combined with same-site ablation, we found dramatic differences between the local and distant tumor environments, where the directly treated tumors were skewed to high expression of F4/80, Cd11b and Tnf and the distant tumors to enhanced Cd11c, Cd3 and Ifng. When ablation was added to immunotherapy, 100% (n=20/20) of directly treated tumors and 90% (n=18/20) of distant tumors were responsive. Comparing the combined ablation-immunotherapy treatment to immunotherapy alone, we find three major mechanistic differences. First, while ablation alone enhanced intratumoral antigen cross-presentation (up to ~8% of CD45+ cells), systemic cross-presentation of tumor antigen remained low. Combining same-site ablation with CpG amplified cross-presentation in the draining lymph node (~16% of CD45+ cells) compared to the ablation-only (~0.1% of CD45+ cells) and immunotherapy-only cohorts (~10% of CD45+ cells). Macrophages and DCs process and present this antigen to CD8+ T-cells, increasing the number of unique T-cell receptor rearrangements in distant tumors. Second, type I interferon (IFN) release from tumor cells increased with the ablation-immunotherapy treatment as compared with ablation or immunotherapy alone. Type I IFN release is synergistic with toll-like receptor activation in enhancing cytokine and chemokine expression. Expression of genes associated with T-cell activation and stimulation (Eomes, Prf1 and Icos) was 27, 56 and 89-fold higher with ablation-immunotherapy treatment as compared to the no-treatment controls (and 12, 32 and 60-fold higher for immunotherapy-only treatment as compared to the no-treatment controls). Third, we found that the ablation-immunotherapy treatment polarized macrophages and dendritic cells towards a CD169 subset systemically, where CD169+ macrophages are an IFN-enhanced subpopulation associated with dead-cell antigen presentation. Conclusion: While the local and distant responses are distinct, CpG combined with ablative focal therapy drives a highly effective systemic immune response.

    View details for PubMedID 30026870

  • Acoustical structured illumination for super-resolution ultrasound imaging. Communications biology Ilovitsh, T., Ilovitsh, A., Foiret, J., Fite, B. Z., Ferrara, K. W. 2018; 1


    Structured illumination microscopy is an optical method to increase the spatial resolution of wide-field fluorescence imaging beyond the diffraction limit by applying a spatially structured illumination light. Here, we extend this concept to facilitate super-resolution ultrasound imaging by manipulating the transmitted sound field to encode the high spatial frequencies into the observed image through aliasing. Post processing is applied to precisely shift the spectral components to their proper positions in k-space and effectively double the spatial resolution of the reconstructed image compared to one-way focusing. The method has broad application, including the detection of small lesions for early cancer diagnosis, improving the detection of the borders of organs and tumors, and enhancing visualization of vascular features. The method can be implemented with conventional ultrasound systems, without the need for additional components. The resulting image enhancement is demonstrated with both test objects and ex vivo rat metacarpals and phalanges.

    View details for PubMedID 29888748

  • Selective inactivation of enzymes conjugated to nanoparticles using tuned laser illumination CYTOMETRY PART A Ilovitsh, A., Polak, P., Zalevsky, Z., Shefi, O. 2017; 91A (8): 767–74


    We report a novel method for specific deactivation of conjugated enzymes using laser-heated gold nanoparticles. Current methods involve treatment of the entire solution, thereby inactivating all bioactive components. Our method enables inactivation of only a single or subset of targeted enzymes. The selected enzyme is pre-conjugated to gold nanoparticles, which are specifically heated by a laser tuned to their surface plasmon resonance. We demonstrate inactivation of a selected enzyme, glucose oxidase, within a mixture of biomolecules. Illumination of non-conjugated enzymes and nanoparticles demonstrated specificity. We propose a novel method to quantitatively regulate enzyme activity, providing a building block for cellular and cell-free biochemical reactions. © 2016 International Society for Advancement of Cytometry.

    View details for DOI 10.1002/cyto.a.23005

    View details for Web of Science ID 000408333700005

    View details for PubMedID 27911977

  • Supersonic transient magnetic resonance elastography for quantitative assessment of tissue elasticity PHYSICS IN MEDICINE AND BIOLOGY Liu, Y., Liu, J., Fite, B. Z., Foiret, J., Ilovitsh, A., Leach, J., Dumont, E., Caskey, C. F., Ferrara, K. W. 2017; 62 (10): 4083–4106


    Non-invasive, quantitative methods to assess the properties of biological tissues are needed for many therapeutic and tissue engineering applications. Magnetic resonance elastography (MRE) has historically relied on external vibration to generate periodic shear waves. In order to focally assess a biomaterial or to monitor the response to ablative therapy, the interrogation of a specific region of interest by a focused beam is desirable and transient MRE (t-MRE) techniques have previously been developed to accomplish this goal. Also, strategies employing a series of discrete ultrasound pulses directed to increasing depths along a single line-of-sight have been designed to generate a quasi-planar shear wave. Such 'supersonic' excitations have been applied for ultrasound elasticity measurements. The resulting shear wave is higher in amplitude than that generated from a single excitation and the properties of the media are simply visualized and quantified due to the quasi-planar wave geometry and the opportunity to generate the wave at the site of interest. Here for the first time, we extend the application of supersonic methods by developing a protocol for supersonic transient magnetic resonance elastography (sst-MRE) using an MR-guided focused ultrasound system capable of therapeutic ablation. We apply the new protocol to quantify tissue elasticity in vitro using biologically-relevant inclusions and tissue-mimicking phantoms, compare the results with elasticity maps acquired with ultrasound shear wave elasticity imaging (US-SWEI), and validate both methods with mechanical testing. We found that a modified time-of-flight (TOF) method efficiently quantified shear modulus from sst-MRE data, and both the TOF and local inversion methods result in similar maps based on US-SWEI. With a three-pulse excitation, the proposed sst-MRE protocol was capable of visualizing quasi-planar shear waves propagating away from the excitation location and detecting differences in shear modulus of 1 kPa. The techniques demonstrated here have potential application in real-time in vivo lesion detection and monitoring, with particular significance for image-guided interventions.

    View details for PubMedID 28426437

    View details for PubMedCentralID PMC5545104

  • Superresolved nanoscopy using Brownian motion of fluorescently labeled gold nanoparticles APPLIED OPTICS Ilovitsh, T., Ilovitsh, A., Wagner, O., Zalevsky, Z. 2017; 56 (5): 1365–69
  • Time multiplexing based geometrical aberrations correction OPTICS LETTERS Ilovitsh, A., Rand, G., Levavi, S., Zalevsky, Z. 2016; 41 (18): 4257–60


    The use of the time-multiplexing super-resolution method for extending the depth of focus of an imaging system was recently presented [Opt. Lett.41, 183 (2016)OPLEDP0146-959210.1364/OL.41.000183]. It involved changing the encoding and decoding gratings frequencies, which determine the optical transfer function duplications positions, and by that obtaining an extended depth of focus. In this Letter we expand this method by showing its applicability for correcting geometrical aberrations of an imaging lens. The proposed method is presented analytically, and validated experimentally for chromatic aberration, spherical aberration, and astigmatism aberration.

    View details for DOI 10.1364/OL.41.004257

    View details for Web of Science ID 000384126300028

    View details for PubMedID 27628371

  • Time multiplexing based extended depth of focus imaging OPTICS LETTERS Ilovitsh, A., Zalevsky, Z. 2016; 41 (1): 183–86


    We propose to utilize the time multiplexing super resolution method to extend the depth of focus of an imaging system. In standard time multiplexing, the super resolution is achieved by generating duplication of the optical transfer function in the spectrum domain, by the use of moving gratings. While this improves the spatial resolution, it does not increase the depth of focus. By changing the gratings frequency and, by that changing the duplication positions, it is possible to obtain an extended depth of focus. The proposed method is presented analytically, demonstrated via numerical simulations and validated by a laboratory experiment.

    View details for DOI 10.1364/OL.41.000183

    View details for Web of Science ID 000380908300005

    View details for PubMedID 26696189

  • Three dimensional imaging of gold-nanoparticles tagged samples using phase retrieval with two focus planes SCIENTIFIC REPORTS Ilovitsh, T., Ilovitsh, A., Weiss, A., Meir, R., Zalevsky, Z. 2015; 5: 15473


    Optical sectioning microscopy can provide highly detailed three dimensional (3D) images of biological samples. However, it requires acquisition of many images per volume, and is therefore time consuming, and may not be suitable for live cell 3D imaging. We propose the use of the modified Gerchberg-Saxton phase retrieval algorithm to enable full 3D imaging of gold-particle tagged samples using only two images. The reconstructed field is free space propagated to all other focus planes using post processing, and the 2D z-stack is merged to create a 3D image of the sample with high fidelity. Because we propose to apply the phase retrieving on nano particles, the regular ambiguities typical to the Gerchberg-Saxton algorithm, are eliminated. The proposed concept is presented and validated both on simulated data as well as experimentally.

    View details for DOI 10.1038/srep15473

    View details for Web of Science ID 000363395100001

    View details for PubMedID 26498517

    View details for PubMedCentralID PMC4620448

  • Super resolved optical system for objects with finite sizes using circular gratings OPTICS EXPRESS Ilovitsh, A., Mico, V., Zalevsky, Z. 2015; 23 (18): 23667–79


    We present a real time all optical super resolution method for exceeding the diffraction limit of an imaging system which has a circular aperture. The resolution improvement is obtained using two fixed circular gratings which are placed in predetermined positions. The circular gratings generate synthetic circular duplications of the aperture, thus they are the proper choice for a circular aperture optical system. The method is applicable for both spatially coherent and incoherent illuminations, as well as for white light illumination. The resolution improvement is achieved by limiting the object field of view. The proposed method is presented analytically, demonstrated via numerical simulations, and validated by laboratory experiments.

    View details for DOI 10.1364/OE.23.023667

    View details for Web of Science ID 000362419900063

    View details for PubMedID 26368464

  • Super-resolution using Barker-based array projected via spatial light modulator OPTICS LETTERS Ilovitsh, A., Ilovitsh, T., Preter, E., Levanon, N., Zalevsky, Z. 2015; 40 (8): 1802–5


    The use of a two-dimensional Barker-based array in the conventional time multiplexing super-resolution (TMSR) technique was recently presented [Opt. Lett.40, 163-165 (2015)OPLEDP0146-959210.1364/OL.40.000163]. It enables achieving a two-dimensional SR image using only a one-dimensional scan, by exploiting its unique auto-correlation property. In this Letter, we refine the method using a mismatched array for the decoding process. The cross-correlation between the Barker-based array and the mismatched array has a perfect peak-to-sidelobes ratio, making it ideal for the SR process. Also, we propose the projection of this array onto the object using a phase-only spatial light modulator. Projecting the array eliminates the need for printing it, mechanically shifting it, and having a direct contact with the object, which is not feasible in many imaging applications. 13 phase masks, which generate shifted Barker-based arrays, were designed using a revised Gerchberg-Saxton algorithm. A sequence of 13 low resolution images were captured using these phase masks, and were decoded using the mismatched arrays, resulting in a high-resolution image. The proposed mismatched array and the design process of the phase masks are presented, and the method is validated by a laboratory experiment.

    View details for DOI 10.1364/OL.40.001802

    View details for Web of Science ID 000353920100048

    View details for PubMedID 25872078

  • Superresolved labeling nanoscopy based on temporally flickering nanoparticles and the K-factor image deshadowing BIOMEDICAL OPTICS EXPRESS Ilovitsh, T., Danan, Y., Ilovitsh, A., Meiri, A., Meir, R., Zalevsky, Z. 2015; 6 (4): 1262–72


    Localization microscopy provides valuable insights into cellular structures and is a rapidly developing field. The precision is mainly limited by additive noise and the requirement for single molecule imaging that dictates a low density of activated emitters in the field of view. In this paper we present a technique aimed for noise reduction and improved localization accuracy. The method has two steps; the first is the imaging of gold nanoparticles that labels targets of interest inside biological cells using a lock-in technique that enables the separation of the signal from the wide spread spectral noise. The second step is the application of the K-factor nonlinear image decomposition algorithm on the obtained image, which improves the localization accuracy that can reach 5nm and enables the localization of overlapping particles at minimal distances that are closer by 65% than conventional methods.

    View details for DOI 10.1364/BOE.6.001262

    View details for Web of Science ID 000352228400014

    View details for PubMedID 25909010

    View details for PubMedCentralID PMC4399665

  • Time multiplexing super resolution using a Barker-based array OPTICS LETTERS Ilovitsh, A., Preter, E., Levanon, N., Zalevsky, Z. 2015; 40 (2): 163–65


    We propose the use of a new encoding mask in order to improve the performance of the conventional time multiplexing super resolution method. The resolution improvement is obtained using a 2D Barker-based array that is placed upon the object and shifted laterally. The Barker-based array is a 2D generalization of the standard 1D Barker code. The Barker-based array has stable autocorrelation sidelobes, making it ideal for the encoding process. A sequence of low resolution images are captured at different positions of the array, and are decoded properly using the same array. After removing the low resolution image from the resulting reconstruction, a high resolution image is established. The proposed method is presented analytically, demonstrated via numerical simulation, and validated by laboratory experiment.

    View details for DOI 10.1364/OL.40.000163

    View details for Web of Science ID 000347939500009

    View details for PubMedID 25679834

  • Optical realization of the radon transform OPTICS EXPRESS Ilovitsh, T., Ilovitsh, A., Sheridan, J., Zalevsky, Z. 2014; 22 (26): 32301–7


    This paper presents a novel optical system for the realization of the Radon transform in a single frame. The optical system is simple, fast and accurate and consists of a 4F system, where in the 2F plane a vortex like optical element is placed. This optical element performs the rotation of the object, which replaces the need for mechanically rotating it, as is done in other common optical realization techniques of the Radon transform. This optical element is realized using a spatial light modulator (SLM) and an amplitude slide. The obtained Radon transform is given in Cartesian coordinates, which can subsequently be transformed using a computer to a polar set. The proposed concept is supported mathematically, numerically and experimentally.

    View details for DOI 10.1364/OE.22.032301

    View details for Web of Science ID 000347179300066

    View details for PubMedID 25607195

  • Super resolved passive imaging of remote moving object on top of sparse unknown background APPLIED OPTICS Ilovitsh, A., Zalevsky, Z. 2014; 53 (28): 6340–43


    A new passive method for improving the contour resolution of a moving object and overcoming the diffraction limit without having any a priori information is presented. The resolution improvement is obtained using a sequence of low-resolution images taken at different positions of an unknown object moving in respect to an unknown background. The super resolving process has two steps. First, a high-resolution estimation of the background is reconstructed using a deconvolution algorithm. Second, the captured set of low-resolution images is decoded by the deconvolved background, and a high-resolution image of the object's contour is generated.

    View details for DOI 10.1364/AO.53.006340

    View details for Web of Science ID 000343159300002

    View details for PubMedID 25322216

  • Time Multiplexing Super Resolving Technique for Imaging from a Moving Platform Jove-Journal of Visualized Experiments Ilovitsh, A., Zach, S., Zalevsky, Z. 2014: e51148


    We propose a method for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained in a two-step process. First, three low resolution differently defocused images are being captured and the optical phase is retrieved using an improved iterative Gerchberg-Saxton based algorithm. The phase retrieval allows to numerically back propagate the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the Synthetic Aperture Radar (SAR) in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated through laboratory experiment.

    View details for DOI 10.3791/51148

    View details for Web of Science ID 000348604100045

    View details for PubMedID 24561625

    View details for PubMedCentralID PMC4123478

  • "Beating speckles'' via electrically-induced vibrations of Au nanorods embedded in sol-gel SCIENTIFIC REPORTS Ritenberg, M., Beilis, E., Ilovitsh, A., Barkai, Z., Shahmoon, A., Richter, S., Zalevsky, Z., Jelinek, R. 2014; 4: 3666


    Generation of macroscopic phenomena through manipulating nano-scale properties of materials is among the most fundamental goals of nanotechnology research. We demonstrate cooperative "speckle beats" induced through electric-field modulation of gold (Au) nanorods embedded in a transparent sol-gel host. Specifically, we show that placing the Au nanorod/sol-gel matrix in an alternating current (AC) field gives rise to dramatic modulation of incident light scattered from the material. The speckle light patterns take form of "beats", for which the amplitude and frequency are directly correlated with the voltage and frequency, respectively, of the applied AC field. The data indicate that the speckle beats arise from localized vibrations of the gel-embedded Au nanorods, induced through the interactions between the AC field and the electrostatically-charged nanorods. This phenomenon opens the way for new means of investigating nanoparticles in constrained environments. Applications in electro-optical devices, such as optical modulators, movable lenses, and others are also envisaged.

    View details for DOI 10.1038/srep03666

    View details for Web of Science ID 000329843800001

    View details for PubMedID 24413086

    View details for PubMedCentralID PMC3888977

  • Optical synthetic aperture radar JOURNAL OF MODERN OPTICS Ilovitsh, A., Zach, S., Zalevsky, Z. 2013; 60 (10): 803–7
  • Contour superresolved imaging of static ground targets using satellite platform APPLIED OPTICS Ilovitsh, A., Zach, S., Zalevsky, Z. 2012; 51 (24): 5863–68


    We propose a method for increasing the contour resolution of static ground targets and to overcome the diffraction limit of an optical system installed on top of a satellite. The resolution improvement is obtained by using a sequence of low-resolution images taken from different angles realized by the movement of the satellite platform. The superresolving process is obtained by the generation of relative movement between the inspected object and the a priori known high-resolution background. The relative movement is caused because the images are taken from different angles. The captured set of low-resolution images are decoded by the a priori known high-resolution background obtained from a set of reference images taken only once by a high-resolution camera. The proposed concept is demonstrated via Matlab simulation and laboratory experiments.

    View details for DOI 10.1364/AO.51.005863

    View details for Web of Science ID 000308076600015

    View details for PubMedID 22907014