Recent ucla_ece items

Feed-forward CEP stabilization revisited: a lower-bound on out-of-loop phase noise

Mon, 8 Jun 2026 00:00:00 +0000

Feed-forward CEP stabilization revisited: a lower-bound on out-of-loop phase noise

Modeling Feedback Bandwidth Limits for Carrier-Envelope Phase Stabilization

Mon, 8 Jun 2026 00:00:00 +0000

Modeling Feedback Bandwidth Limits for Carrier-Envelope Phase Stabilization

Validating Single-Pulse Stability of the SESAM Mode-Locked Er:Yb:glass Oscillator Underlying Feed-Forward CEP Stabilization

Sun, 7 Jun 2026 00:00:00 +0000

Validating Single-Pulse Stability of the SESAM Mode-Locked Er:Yb:glass Oscillator Underlying Feed-Forward CEP Stabilization

Sub-Hz Noise Dominance in Feed-Forward Carrier-Envelope Phase Stabilization

Sun, 7 Jun 2026 00:00:00 +0000

Sub-Hz drift dominates full-band phase noise of the feed-forward system. This review models its mechanisms through phase-noise integration and transfer functions.

Critical Review: Carrier-Envelope Phase Stabilization of an Er:Yb:Glass Laser via Feed-Forward Technique

Sun, 7 Jun 2026 00:00:00 +0000

Critical Review: Carrier-Envelope Phase Stabilization of an Er:Yb:Glass Laser via Feed-Forward Technique

Role of Upper-State Lifetime in Carrier-Envelope Phase Control of Er:Yb:glass Lasers

Sun, 7 Jun 2026 00:00:00 +0000

We critically review carrier-envelope phase stabilization of Er:Yb:glass mode-locked lasers, reproducing attosecond-level jitter and illustrating that millisecond-level upper-state lifetime limits bandwidth, forcing a hybrid feed-forward/feedback architecture and motivating fast intracavity actuation.

PERCEL: A Re-Writable NVM CIM Incorporating a CTT-Based Per-Cell DAC

Tue, 12 May 2026 00:00:00 +0000

Compute in memory (CiM) accelerators perform matrix vector multiplications (MVMs) directly inside memory arrays, reducing data movement and improving both energy efficiency and throughput for AI workloads. To reduce the number of conversions, recent designs use multi-bit compute cells. Nevertheless, practical multi-bit CiM still faces a tension between accuracy, efficiency, and re-writeability, since multi-level NVM based designs suffer from nonlinearity and poor re-writeability, while multi-level activation based DRAM / SRAM macros are limited by mismatch and low accuracy. This work introduces a per-cell DAC based CiM macro that combines the density of multi-level NVM with fully re-writable DRAM weights to break the trade-off. Each bit cell embeds a compact 6-bit CTT based current mode DAC, calibrated in-situ through a write verify write loop, together with a 1T(1C) embedded DRAM. Post-layout simulations of a 576×256 macro in 22nm FDSOI project 49.9 8b-TOPS/W, and 8.96 8b-TOPS/mm2,...

Deep learning-enhanced dual-mode multiplexed optical sensor for point-of-care diagnostics of cardiovascular diseases.

Fri, 10 Apr 2026 00:00:00 +0000

Rapid and accessible cardiac biomarker testing is essential for the timely diagnosis and risk assessment of myocardial infarction (MI) and heart failure (HF), two interrelated conditions that frequently coexist and drive recurrent hospitalizations with high mortality. However, current laboratory and point-of-care testing systems are limited by long turnaround times, narrow dynamic ranges for the tested biomarkers, and single-analyte formats that fail to capture the complexity of cardiovascular disease. Here, we present a deep learning-enhanced dual-mode multiplexed vertical flow assay (xVFA) with a portable optical reader and a neural network-based quantification pipeline. This optical sensor integrates colorimetric and chemiluminescent detection within a single paper-based cartridge to complementarily cover a large dynamic range (spanning ~6 orders of magnitude) for both low- and high-abundance biomarkers, while maintaining quantitative accuracy. Using 50 µL of serum, the optical...

Diagnostic x-ray source using electrons produced by a 100 J-class picosecond laser

Wed, 1 Apr 2026 00:00:00 +0000

Many laser-based high-energy-density science (HEDS) facilities have one or more short-pulse (sub- to few-picosecond) laser beams for diagnostics. For the past decade, we have been developing a novel x-ray probing capability using such picosecond lasers interacting with an underdense plasma to produce relativistic electrons. The ultimate goal of these experiments is to demonstrate a new type of x-ray backlighter using the short-pulse ARC laser at the National Ignition Facility (NIF). Before this diagnostic is fielded at the NIF, it is critical to demonstrate the viability and reproducibility of the x-ray source on comparable high-power short-pulse laser systems. We present experiments that were carried out with the OMEGA EP laser at the University of Rochester’s laboratory for laser energetics. In these experiments, high-energy electrons are produced through a combination of the self-modulation instability and direct laser acceleration in an underdense gas jet. These electrons...

Dictionary Learning for Phase-Less Beam Alignment Codebook Design in Multipath Channels

Wed, 11 Feb 2026 00:00:00 +0000

Large antenna arrays are critical for reliability and high data rates in wireless networks at millimeter-wave and sub-terahertz bands. While traditional methods for initial beam alignment for analog phased arrays scale beam alignment overhead linearly with the array size, compressive sensing (CS) and machine learning (ML) algorithms can scale logarithmically. CS and ML methods typically utilize pseudo-random or heuristic beam designs as compressive codebooks. However, these codebooks may not be optimal for scenarios with uncertain array impairments or multipath, particularly when measurements are phase-less or power-based. In this work, we propose a novel dictionary learning method to design codebooks for phase-less beam alignment given multipath and unknown impairment statistics. This codebook learning algorithm uses an alternating optimization with block coordinate descent to update the codebooks and Monte Carlo trials over multipath and impairments to incorporate a-priori knowledge...

Robustness Analysis of Laguerre-Gaussian Mode Laser Heaters: Defining the Transverse Jitter Threshold for Microbunching Instability Suppression