arXiv subjects

Kaifeng Shi

Publications and source records attributed to Kaifeng Shi.

8 recordsLinked to original sources

arXiv2026

Owner3D: Ownership-Guided Style Writing for Training-Free Localized 3D Stylization

Localized 3D stylization aims to modify the appearance of a specified object part while preserving the remaining surfaces. In large reconstruction models (LRMs), this task is challenging because style is injected into intermediate appearance representations before rendering, while compact triplane features are shared across target and non-target surfaces, causing style leakage and boundary ambiguity. We propose Owner3D, a training-free framework for localized 3D stylization that integrates localized appearance control directly into the LRM reconstruction process. Specifically, Owner3D introduces ownership-guided style writing to restrict reference-style injection to target regions, producing a single localized stylized triplane without additional training while avoiding separate global style and appearance representations. To resolve appearance ambiguity near semantic boundaries, we further introduce boundary dual slots that maintain separate local feature sources for target and non-target regions. Finally, a surface-first texture readout hierarchically combines surface, 3D, and triplane ownership evidence to robustly recover appearance under incomplete visibility. Experiments on a benchmark constructed from Google Scanned Objects and PartNet demonstrate that Owner3D consistently outperforms existing 3D stylization methods in target-region style fidelity and non-target appearance preservation, reducing appearance leakage by 86.4% and 89.9% compared with StyleSplat and LAENeRF, respectively.

cs.CV↗

arXiv2016

Fiber-to-Waveguide and 3D Chip-to-Chip Light Coupling Based on Bent Metal-Clad Waveguides

Efficient fiber-to-waveguide light coupling has been a key issue in integrated photonics for many years. The main challenge lies in the huge mode mismatch between an optical fiber and a single mode waveguide. Herein, we present a novel fiber-to-waveguide coupler, named "L-coupler", through which the light fed from the top of a chip can bend 90° with low reflection and is then efficiently coupled into an on-chip Si waveguide within a short propagation distance (<20μm). The key element is a bent metal-clad waveguide with a big matched input port. According to our finite-difference time-domain (FDTD) simulation, the coupling efficiency is over 80% within a broad range of working wavelengths in the near-infrared regime for a transverse electric input Gaussian wave. The coupler is polarization-dependent, with very low coupling efficiency (6%-9%) for transverse magnetic waves. The coupler can also be used for three-dimensional (3D) chip-to-chip optical interconnection by efficiently coupling light into an integrated photonic chip from a vertical-cavity surface-emitting laser (VCSEL), or Si waveguide on another chip. The work presented in this Arxiv article has been filed as a patent. Detailed description of this work may be published in future papers.

physics.optics↗

arXiv2015

Nanoscale Field Effect Optical Modulators Based on Depletion of Epsilon-Near-Zero Films

The field effect in metal-oxide-semiconductor (MOS) capacitors plays a key role in field-effect transistors (FETs), which are the fundamental building blocks of modern digital integrated circuits. Recent works show that the field effect can also be used to make optical/plasmonic modulators. In this paper, we report field effect electro-absorption modulators (FEOMs) each made of an ultrathin epsilon-near-zero (ENZ) film, as the active material, sandwiched in a silicon or plasmonic waveguide. Without a bias, the ENZ film maximizes the attenuation of the waveguides and the modulators work at the OFF state; contrariwise, depletion of the carriers in the ENZ film greatly reduces the attenuation and the modulators work at the ON state. The double capacitor gating scheme is used to enhance the modulation by the field effect. According to our simulation, extinction ratio up to 3.44 dB can be achieved in a 500-nm long Si waveguide with insertion loss only 0.71 dB (85.0%); extinction ratio up to 7.86 dB can be achieved in a 200-nm long plasmonic waveguide with insertion loss 1.11 dB (77.5%). The proposed modulators may find important applications in future on-chip or chip-to-chip optical interconnection.

physics.optics↗

arXiv2015

Ultracompact Field Effect Electro-Absorption Plasmonic Modulator

One of the technical barriers impeding the wide applications of integrated photonic circuits is the lack of ultracompact, high speed, broadband electro-optical (EO) modulators, which up-convert electronic signals into high bit-rate photonic data. In addition to direct modulation of lasers, EO modulators can be classified into (i) phase modulation based on EO effect or free-carrier injection, or (ii) absorption modulation based on Franz-Keldysh effect or quantum-confined Stark effect. Due to the poor EO properties of regular materials, a conventional EO modulator has a very large footprint. Based on high-Q resonators, recent efforts have advanced EO modulators into microscale footprints, which have nearly reached their physical limits restricted by the materials. On-chip optical interconnects require ultrafast EO modulators at the nanoscale. The technical barrier may not be well overcome based on conventional approaches and well-known materials. Herein, we report an EO modulator, more specifically electro-absorption (EA) modulator, based on the integration of a novel yet inexpensive active material, indium tin oxide (ITO), in a metal-insulator-metal (MIM) plasmonic waveguide platform, where the field effect is then greatly enhanced by high-k insulator and double capacitor gating scheme. The modulator waveguide length is only 800 nm, which is the smallest recorded dimension according to our knowledge. Preliminary results show that it has extinction ratio of 1.75 (2.43 dB) at 10 MHz, works up to 500 MHz (limited by testing setup for now), and can potentially operate at high speed.

physics.optics↗

arXiv2015

Photonic MOS Based on "Optical Property Inversion"

Most dielectric materials have very weak electro-optic properties, whereas the optical properties of some plasmonic materials may be greatly tuned, especially around their plasma frequency, where dielectric constant is transiting between positive ("dielectric state") and negative ("metallic state") values. In this report, we will review some of our recent work on electro-optical modulation and introduce a new concept, photonic MOS based on "optical property inversion". This concept may provide inspiration for the development of nanophotonic devices. Some of the material was adapted from unfunded NSF proposals.

physics.optics↗

arXiv2015

Efficient Electro-Optical Modulation Based on Indium Tin Oxide

We experimentally demonstrate several electro-optical modulators based on transparent conducting oxides. Our previous work demonstrated the modulator structure on glass substrate with broadband bias polarity-dependent modulation. Further exploration shows similar modulation effect of the modulator on quartz and silicon substrate.

physics.optics↗

arXiv2013

Ultrabroad-Band, Greatly Enhanced Light Absorption by Monolayer Graphene

We demonstrate greatly enhanced light absorption by monolayer graphene over a broad spectral range, from visible to near infrared, based on the attenuated total reflection. In the experiment, graphene is sandwiched between two dielectric media referred as superstrate and substrate. Based on numerical calculation and experimental results, the closer the refractive indices of the superstrate and the substrate, the higher the absorption of graphene will be. The light absorption of monolayer graphene up to 42.7% is experimentally achieved.

physics.optics↗

arXiv2012

Nanoscale Plasmonic and Optical Modulators Based on Transparent Conducting Oxides

Recent experiments showed that unity-order index change in a transparent conducting oxide (TCO) can be achieved in a metal-oxide-semiconductor (MOS) structure by accumulation charge. However, the ultrathin (~5nm) accumulation layer and inherent absorption of TCOs impede the practical applications of this effect. Herein, we propose and explore a novel waveguide, namely "TCO-slot waveguide", which combines both the tunable property of a TCO and field enhancement of a slot waveguide. In particular, light absorption can be sharply enhanced when the slot dielectric constant is tuned close to zero. Based on TCO-slot waveguides, efficient electro-absorption modulation can be achieved within 200 nm with small insertion loss.

physics.optics↗