Related papers: A Millimeter-Wave Achromatic Half Wave Plate
Modal phase matching (MPM) is a widely used phase matching technique in Al$_x$Ga$_{1-x}$As and other $\chi^{(2)}$ nonlinear waveguides for efficient wavelength conversions. The use of a non-fundamental spatial mode compensates the material…
A single layer broadband millimetre wave (mm-wave) array with circular polarisation is proposed for the fifth generation (5G) mm-wave communication applications. The antenna element is designed to integrate the matching circuit into a…
In this paper, we report measurements of diffraction efficiency and angular dispersion for a large format (~ 25 cm diameter) Volume-Phase Holographic (VPH) grating optimized for near-infrared wavelengths (0.9 -- 1.8 micron). The aim of this…
An all-dielectric Huygens metasurface supporting electric and magnetic resonances is a promising platform for a variety of optical applications that require a combination of extremely high transmission and broad-range control of the phase…
In this letter, a dual port antenna with polarization adjustability is proposed. The loading effect of four ring slots stimulates a hybrid mode in the antenna that generates eight magnetic monopoles with high gain in boresight. Due to…
We investigate the hemispherical power asymmetry in the cosmic microwave background on small angular scales. We find an anomalously high asymmetry in the multipole range l=601-2048, with a naive statistical significance of 6.5 sigma.…
In the second part of our series on integrated photonic spectrographs for astronomy, we present theoretical and experimental results on the design, simulation and characterization of custom-manufactured silica-on-silicon Arrayed Waveguide…
The propagation of electromagnetic waves in the anisotropic medium with a single-sheeted hyperboloid dispersion relation is investigated. It is found that in such an anisotropic medium E- and H-polarized waves have the same dispersion…
We describe the design and performance of a microwave polarimeter used to make precision measurements of polarized astrophysical radiation in three microwave frequency bands spanning 26-36 GHz. The instrument uses cooled HEMT amplifiers in…
A method of measuring the thickness of steel plates using through transmission of an acoustic pulse is demonstrated. This study has been done on a stainless steel plate with regions of thickness 10:0 mm, 9:8 mm, and 9:6 mm, using broadband…
Recently, an achromatic metasurface was successfully demonstrated to deflect light of multiple wavelengths in the same direction and it was further applied to the design of planar lenses without chromatic aberrations [Science, 347,…
The primary goal of the MAP satellite, now in orbit, is to make high fidelity polarization sensitive maps of the full sky in five frequency bands between 20 and 100 GHz. From these maps we will characterize the properties of the cosmic…
We present a numerical and experimental study of the impact of phase errors on the performance of large, high-resolution Arrayed Waveguide Gratings (AWG) for applications in astronomy. We use a scalar diffraction model to study the…
Asymmetric propagation of acoustic waves is theoretically reported in a chirped phononic crystal made of the combination of two different nonlinear solids. The dispersion of the system is spatially dependent and allows the rainbow trapping…
We used two novel approaches to produce sub-wavelength structure (SWS) anti-reflection coatings (ARC) on silicon for the millimeter and sub-millimeter (MSM) wave band: picosecond laser ablation and dicing with beveled saws. We produced…
Metasurfaces are nano-structured devices composed of arrays of subwavelength scatterers (or meta-atoms) that manipulate the wavefront, polarization, or intensity of light. Like other diffractive optical devices, metasurfaces suffer from…
This paper presents the design and fabrication of leaky-wave holograms with anisotropic properties, enabling circular polarization for single-beam radiation in desired directions. Tailored for future terrestrial networks like 5G, 6G, and…
The metalenses have been extensively studied for their compact and flexible characteristics in focusing and imaging applications. However, it remains a significant challenge to design a broadband achromatic metalens that maintains high…
Broadband low-resolution near-infrared spectrographs in a compact form are crucial for ground- and space-based astronomy and other fields of sensing. Astronomical spectroscopy poses stringent requirements including high efficiency, broad…
We present first results of Hertz/VPM, the first submillimeter polarimeter employing the dual Variable-delay Polarization Modulator (dual-VPM). This device differs from previously used polarization modulators in that it operates in…