- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Deflecting transmissive light beams with metasurfaces based on crystalline silicon high-contrast grating
摘要： Dielectric metasurfaces have emerged and expanded rapidly for their success in realizing high-efficiency wavefront control in the optical and infrared ranges. However, devices have either been demonstrated at near-infrared regime using high-index semiconductors such as silicon, or they use lower index dielectric materials such as TiO2 or Si3N4 and operate in the visible wavelength regime to avoid the optical loss of dielectric materials. It seems that dielectric metasurfaces could not achieve either high index or high device efficiency, simultaneously. Here, we provide a crystalline silicon metasurface scheme to efficiently modulate transmitted light beams at the wavelengths as short as to 532 nm. The unit cell of the metasurfaces consists of high-contrast grating (HCG), which provides full 2π phase control for circular polarized incident beams in thin film. The demonstration of HCG deflector shows that the device enables high deflecting efficiency as high as those made by transparent materials. Our results provide a paradigm to functionalize transmitted light beams based on crystalline silicon in the visible wavelength regime.
关键词： dielectric metasurfaces,high-contrast grating,diffractive optics,crystalline silicon
更新于2025-09-23 15:19:57
-
Demonstration of polarization control GaN-based micro-cavity lasers using a rigid high-contrast grating reflector
摘要： We reported on Gan microcavity (Mc) lasers combined with one rigid tio2 high-contrast grating (HcG) structure as the output mirror. the HcG structure was directly fabricated on the Gan structure without an airgap. The entire MC structure comprised a bottom dielectric distributed Bragg reflector; a GaN cavity; and a top HCG reflector, which was designed to yield high reflectance for transverse magnetic (tM)- or transverse electric (te)-polarized light. the Mc device revealed an operation threshold of approximately 0.79 MW/cm2 when pulsed optical pumping was conducted using the HcG structure at room temperature. The laser emission was TM polarized with a degree of polarization of 99.2% and had a small divergence angle of 14° (full width at half maximum). This laser operation demonstration for the Gan-based Mc structure employing an HcG exhibited the advantages of HcGs in semiconductor lasers at wavelengths from green to ultraviolet.
关键词： Gan microcavity lasers,high-contrast grating reflector,GaN,polarization control,TiO2
更新于2025-09-11 14:15:04
-
Improving the Performance of the Optical Antenna for Integrated LIDAR with Optical Phased Arrays through High Contrast Grating Structure on SOI Substrate
摘要： A novel optical antenna for integrated LIDAR with optical phased arrays is proposed and simulated. A HCG structure is used to achieve extremely efficient emission. The emission efficiency is as high as 93.94% at 1550 nm, which exceeds 50% in a range of wavelength from 1480 nm to 1620 nm. The antenna can achieve a perfect grating lobe suppression with background suppression of 28.4dB when the phase difference between adjacent waveguides is 0. A 16-wire optical phased arrays LIDAR can easily achieve a scan range of ±22.8°×20.2° with a beam width of 2.4°×2.5°, by employing the optical antenna proposed.
关键词： SOI substrate,high contrast grating,optical phased arrays,LIDAR,optical antenna
更新于2025-09-10 09:29:36