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In the last decade, advancements in attosecond spectroscopy have allowed us to study electron motion dynamics in condensed matter. The access to these electron dynamics and, consequently, its control by an ultrafast light field paves the way for establishing ultrafast optoelectronics. Here, we report the generation of light-induced quantum tunnelling current in graphene phototransistors by ultrafast laser pulses in an ambient environment. This tunnelling effect provides access to the instantaneous field-driven current to demonstrate the current switching (ON and OFF) on a 630 attosecond (1.6 petahertz speed). Moreover, we controlled the tunnelling current and enhanced the graphene phototransistor conductivity by controlling the density of the photoexcited charge carriers at different pump laser powers. Furthermore, we exploited this capability to demonstrate various logic gates. The demonstrated light-induced tunnelling current and ultrafast switching were attained under standard room temperature and pressure conditions. Therefore, the presented scientific advancement in this work is at the technology readiness level suitable for its immediate integration into the development of ultrafast, nearly six orders of magnitude faster, optical transistors, lightwave electronics, and optical quantum computers., Comment: 24 pages and 4 figures

The electron motion in atoms and molecules is at the heart of all phenomena in nature that occur outside the nucleus. Recently, ultrafast electron and X-ray imaging tools have been developed to image the ultrafast dynamics of matter in real time and space. The cutting-edge temporal resolution of these imaging tools is on the order of a few tens to a hundred femtoseconds, limiting imaging to atomic dynamics. Hence electron motion imaging remains beyond the reach. Here, we achieved attosecond electron imaging temporal resolution in a transmission electron microscope, orders of magnitude faster than the highest reported imaging resolution, to demonstrate, which we coin it as (attomicroscopy) to image the field-induced electron dynamics in neutral multilayer graphene. Our results show that the electron motion between the carbon atoms in graphene is due to the field-driven electron dynamics in the conduction band and depends on the field waveform, strength, and polarization direction. This attomicroscopy imaging provides more insights into the electron motion of neutral matter in real time and space and would have long-anticipated real-life attosecond science applications in quantum physics, chemistry, and biology.

With numerous medical tasks, the performance of deep models has recently experienced considerable improvements. These models are often adept learners. Yet, their intricate architectural design and high computational complexity make deploying them in clinical settings challenging, particularly with devices with limited resources. To deal with this issue, Knowledge Distillation (KD) has been proposed as a compression method and an acceleration technology. KD is an efficient learning strategy that can transfer knowledge from a burdensome model (i.e., teacher model) to a lightweight model (i.e., student model). Hence we can obtain a compact model with low parameters with preserving the teacher's performance. Therefore, we develop a KD-based deep model for prostate MRI segmentation in this work by combining features-based distillation with Kullback-Leibler divergence, Lovasz, and Dice losses. We further demonstrate its effectiveness by applying two compression procedures: 1) distilling knowledge to a student model from a single well-trained teacher, and 2) since most of the medical applications have a small dataset, we train multiple teachers that each one trained with a small set of images to learn an adaptive student model as close to the teachers as possible considering the desired accuracy and fast inference time. Extensive experiments were conducted on a public multi-site prostate tumor dataset, showing that the proposed adaptation KD strategy improves the dice similarity score by 9%, outperforming all tested well-established baseline models.

The advancement of the ultrafast pulse shaping and waveform synthesis allowed to coherently control the atomic and electronic motions in matter. The temporal resolution of the waveform synthesis is inversely proportional to the broadening of its spectrum. Here, we demonstrate the light field synthesis of high-power waveforms spanning two optical octaves, from near-infrared (NIR) to deep-ultraviolet (DUV) with attosecond resolution. Moreover, we utilized the all-optical field sampling metrology for on-demand tailoring of light field waveforms to control the electron motion in matter. The demonstrated synthesis of the light field and the electron motion control pave the way for switching the photo-induced current signal in dielectric nanocircuit and establishing ultrafast photonics operating beyond the petahertz speed.

In the last decade, the development of Ultrafast Electron Diffraction (UED) and Microscopy (UEM) has enabled the imaging of atomic motion in real time and space. These pivotal table-top tools opened the door for a vast range of applications in different areas of science spanning chemistry, physics, materials science, and biology. We first discuss the basic principles and recent advancements, including some of the important applications, of both UED and UEM. Then, we discuss the recent advances in the field that have enhanced the spatial and temporal resolutions, where the latter, however, is still limited to a few hundreds of femtoseconds, preventing the imaging of ultrafast dynamics of matter on the scale of several tens of femtoseconds. Then, we present our new optical gating approach for generating an isolated 30 fs electron pulse with sufficient intensity to attain a temporal resolution on the same time scale. This achievement allows, for the first time, imaging the electron dynamics of matter. Finally, we demonstrate the feasibility of the optical gating approach to generate an isolated attosecond electron pulse, utilizing our recently demonstrated optical attosecond laser pulse, which paves the way for establishing the field of Attomicroscopy, ultimately enabling us to image the electron motion in action., Comment: 57 pages, 23 figures