@arXiv_physicsoptics_bot@mastoxiv.page2025-11-25 09:19:33
Graphene and thin graphite films for ultrafast optical Kerr gating at 1 GHz repetition rate under focused illumination
Amr Farrag, Assegid M. Flatae, Mario Agio
https://arxiv.org/abs/2511.17713 https://arxiv.org/pdf/2511.17713 https://arxiv.org/html/2511.17713
arXiv:2511.17713v1 Announce Type: new
Abstract: The ability to address sub-picosecond events of weak optical signals is essential for progress in quantum science, nonlinear optics, and ultrafast spectroscopy. While up-conversion and optical Kerr gating (OKG) offer femtosecond resolution, they are generally limited to ensemble measurements, making ultrafast detection in nano-optics challenging. OKG, with its broadband response and high throughput without phase-matching, is especially promising when used at high repetition rates under focused illumination.
Here, we demonstrate an ultrafast detection scheme using the third-order nonlinearity of graphene and thin graphite films, operating at 1 GHz with sub-nanojoule pulses and achieving 141 fs temporal resolution. Their exceptionally large nonlinear refractive index, orders of magnitude higher than conventional Kerr media, enhances detection efficiency at smaller thicknesses, enables sub-picosecond response, and supports broadband operation. Their atomic-scale thickness minimizes dispersion and simplifies integration with microscopy platforms, optical fibers, and nanophotonic circuits, making them a compact, practical material platform for nano-optical and on-chip ultrafast Kerr gating.
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@cdarwin@c.im2025-12-19 00:35:54
Seeing Life at the Quantum Limit
Congratulations to
Dr Nicolas Mauranyapin,
winner of QUBIC’s inaugural Scientific Achievement Award - Cell Theme!
Nico has built a quantum-limited microscope, so sensitive it operates at the quantum shot noise limit,
the same benchmark used in gravitational wave detection.
This means it can capture the faintest signals nature allows.
This breakthrough enables real-time observation of living cells without damage,
@cdarwin@c.im2025-11-04 01:56:56
Nobel laureate Sir Roger Penrose dismantles standard cosmology,
arguing the Big Bang wasn't the beginning and quantum mechanics is fundamentally wrong.
He then connects a real, gravitational wave function collapse to the non-computational nature of consciousness
and why today's AI can't truly understand
