In this Letter, we propose and experimentally demonstrate the first, to our knowledge, integrated liquid-crystal-based (LC-based) variable-tap devices for visible-light amplitude modulation. These devices leverage the birefringence of LC medium to actively tune the coupling coefficient between two waveguides. First, we develop the device structure, theory of operation, and design procedure. Next, we summarize the fabrication and LC packaging procedure for these devices. Finally, we experimentally demonstrate amplitude modulation with 15.4-dB tap-port extinction within ±3.1 V for a 14-µm-long device at a 637-nm operating wavelength. These small-form-factor variable-tap devices provide a compact and low-power solution to integrated visible-light amplitude modulation and will enable future high-density integrated visible-light systems.
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http://dx.doi.org/10.1364/OL.511189 | DOI Listing |
Adv Sci (Weinh)
January 2025
Shaanxi Key Laboratory of Artificially Structured Functional Materials and Devices, Airforce Engineering University, Xi'an, Shaanxi, 710051, China.
The integrated modulation of radiation and scattering provides an unprecedented opportunity to reduce the number of electromagnetic (EM) apertures in the platform while simultaneously enhancing communication and stealth performance. Nevertheless, achieving full-polarization, arbitrary amplitude, and phase modulation of radiation scattering remains a challenge. In this paper, a strategy that realizes space-time coding of radiation scattering within the same frequency band, which enables the simultaneous and independent modulation of amplitude and phase, is proposed.
View Article and Find Full Text PDFFront Public Health
January 2025
Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, Seoul, Republic of Korea.
Objective: This study assessed the effects of transcranial direct current stimulation (tDCS) on cue reactivity and craving for game-related cues using event-related potentials (ERPs) in internet gaming disorder (IGD) patients.
Methods: At baseline, a series of game-related and neutral pictures were shown to both IGD and healthy controls (HCs) while ERPs were recorded. Late positive potentials (LPP) were used to investigate cue reactivity.
Opt Express
January 2025
The perceived colors of silicon-on-insulator (SOI) wafers with etched Si surface layers of thickness 90 nm to 30 nm vary from turquoise to purple to golden. Measured reflectance curves spanning ultraviolet, visible, and near infrared wavelengths have an amplitude modulated oscillatory pattern. Multilayer reflectance calculations indicate the oscillatory pattern results from the 2 µm thick buried SiO layer which functions as a nearly lossless reflective Fabry-Perot etalon in the near infrared where SiO and Si are transparent.
View Article and Find Full Text PDFAdaptive mode-selective multiplexers offer the potential to control the modal content within multimode fibers for space division multiplexing (SDM). To such an end, spatial light modulators allow programmable control over the phase, amplitude, and polarization of optical wavefronts. One of the major challenges is to precisely match the manipulated beam to the waveguide modes in the multimode fiber.
View Article and Find Full Text PDFGeneration of orthonormal optical fields using phase-only spatial light modulators (SLM) or amplitude-only digital micromirror devices (DMD) is an active and diverse research field, with a wide variety of applications. However, these approaches typically come with limited accuracy, and a significant loss in resolution and intensity. We present a different approach: we construct orthonormal fields that can be generated exactly on phase-only hardware without loss of resolution or intensity.
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