This investigation demonstrates the feasibility of a magnetically tunable liquid crystal phase grating for the terahertz wave. The phase grating can be used as a beam splitter. The ratio of the zeroth and first-order diffracted THz-beams (0.3 THz) polarized in a direction perpendicular to that of the grooves of the grating can be tuned from 4:1 to 1:2. When the THz wave is polarized in any other direction, this device can be operated as a polarizing beam splitter.
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http://dx.doi.org/10.1364/oe.16.002995 | DOI Listing |
Rev Sci Instrum
December 2024
OFS Laboratories, 19 Schoolhouse Road, Somerset, New Jersey 08873, USA.
Transmission matrix measurements of multimode fibers are now routinely performed in numerous laboratories, enabling control of the electric field at the distal end of the fiber and paving the way for the potential application to ultrathin medical endoscopes with high resolution. The same concepts are applicable to other areas, such as space division multiplexing, targeted power delivery, fiber laser performance, and the general study of the mode coupling properties of the fiber. However, the process of building an experimental setup and developing the supporting code to measure the fiber's transmission matrix remains challenging and time consuming, with full details on experimental design, data collection, and supporting algorithms spread over multiple papers or lacking in detail.
View Article and Find Full Text PDFRev Sci Instrum
December 2024
Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400094, India.
We present a comprehensive overview of the commissioning process and initial results of a synchrotron beamline dedicated to atomic, molecular, and optical sciences at the BL-5 undulator port of the Indus-2 synchrotron facility, Raja Ramanna Center for Advanced Technology, Indore, India. The beamline delivers a photon flux of ∼1012 photons/s with high resolving power (∼10 000) over an energy range of 6-800 eV, making it suitable for high-resolution spectroscopy in atomic, molecular, and optical science. The energy tunability from vacuum ultraviolet to soft x-ray (6-800 eV) is achieved through a varied line spacing plane grating monochromator with four gratings: very low energy (VLEG), low energy (LEG), medium energy (MEG), and high energy (HEG).
View Article and Find Full Text PDFMed Phys
December 2024
Research Center for Advanced Detection Materials and Medical Imaging Devices, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China.
Background: The complementary absorption contrast CT (ACT) and differential phase contrast CT (DPCT) can be generated simultaneously from an x-ray computed tomography (CT) imaging system incorporated with grating interferometer. However, it has been reported that ACT images exhibit better spatial resolution than DPCT images. By far, the primary cause of such discrepancy remains unclear.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Photonics Research Group, Department of Electrical and Information Engineering, Politecnico di Bari, 70126 Bari, Italy.
This study explores the achievement of a tunable true time-delay (TTD) system for a microwave phased-array antenna (MPAA) by incorporating the reversible phase-transition property of phase-change material (PCM) with Bragg gratings (BGs) and a cascade of three phase-shifted Bragg grating resonators (CPSBGRs). The goal was to design a low-power-consuming, non-volatile highly tunable compact TTD system for beam steering. A programmable on/off reflector was designed by changing a PCM-incorporated BG/CPSBGR from one phase to another.
View Article and Find Full Text PDFNanophotonics
April 2024
Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Manipulating the thermal emission in the infrared (IR) range significantly impacts both fundamental scientific research and various technological applications, including IR thermal camouflage, information encryption, and radiative cooling. While prior research has put forth numerous materials and structures for these objectives, the significant challenge lies in attaining spatially resolved and dynamically multilevel control over their thermal emissions. In this study, a one-step ultrafast laser writing technique is experimentally demonstrated to achieve position-selective control over thermal emission based on the phase-change material GeSbTe (GST).
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