Spatial Terahertz-Light Modulators for Single-Pixel Cameras

Mapping Intimacies ◽

10.5772/intechopen.96691 ◽

2021 ◽

Author(s):

Rayko Ivanov Stantchev ◽

Emma Pickwell-MacPherson

Keyword(s):

Medical Diagnosis ◽

Imaging Techniques ◽

Terahertz Imaging ◽

Main Section ◽

Light Modulator ◽

Future Directions ◽

Imaging Arrays ◽

Light Modulators ◽

The Future ◽

Single Pixel

Terahertz imaging looks set to become an integral part of future applications from semiconductor quality control to medical diagnosis. This will only become a reality when the technology is sufficiently cheap and capabilities adequate to compete with others. Single-pixel cameras use a spatial light modulator and a detector with no spatial-resolution in their imaging process. The spatial-modulator is key as it imparts a series of encoding masks on the beam and the detector measures the dot product of each mask and the object, thereby allowing computers to recover an image via post-processing. They are inherently slower than parallel-pixel imaging arrays although they are more robust and cheaper, hence are highly applicable to the terahertz regime. This chapter dedicates itself to terahertz single-pixel cameras; their current implementations, future directions and how they compare to other terahertz imaging techniques. We start by outlining the competing imaging techniques, then we discuss the theory behind single-pixel imaging; the main section shows the methods of spatially modulating a terahertz beam; and finally there is a discussion about the future limits of such cameras and the concluding remarks express the authors’ vision for the future of single-pixel THz cameras.

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Compressed sensing in the far-field of the spatial light modulator in high noise conditions

Scientific Reports ◽

10.1038/s41598-021-97072-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Akhil Kallepalli ◽

John Innes ◽

Miles J. Padgett

Keyword(s):

Compressed Sensing ◽

Phased Array ◽

Imaging Techniques ◽

Far Field ◽

Light Modulator ◽

High Noise ◽

Detector Arrays ◽

Phase Modulators ◽

Plane Detector ◽

Single Pixel

AbstractSingle-pixel imaging techniques as an alternative to focal-plane detector arrays are being widely investigated. The interest in these single-pixel techniques is partly their compatibility with compressed sensing but also their applicability to spectral regions where focal planes arrays are simply not obtainable. Here, we show how a phased-array modulator source can be used to create Hadamard intensity patterns in the far-field, thereby enabling single-pixel imaging. Further, we successfully illustrate an implementation of compressed sensing for image reconstruction in conditions of high noise. In combination, this robust technique could be applied to any spectral region where spatial light phase modulators or phased-array sources are available.

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Compressed sensing in the far-field of the spatial light modulator in high noise conditions

10.21203/rs.3.rs-403263/v1 ◽

2021 ◽

Author(s):

Akhil Kallepalli ◽

John Innes ◽

Miles Padgett

Keyword(s):

Compressed Sensing ◽

Phased Array ◽

Imaging Techniques ◽

Far Field ◽

Light Modulator ◽

High Noise ◽

Detector Arrays ◽

Phase Modulators ◽

Plane Detector ◽

Single Pixel

Abstract Single-pixel imaging techniques as an alternative to focal-plane detector arrays are being widely investigated. The interest in these single-pixel techniques is partly their compatibility with compressed sensing but also their applicability to spectral regions where focal planes arrays are simply not obtainable. Here, we show how a phased-array modulator source can be used to create Hadamard intensity patterns in the far-field, thereby enabling single-pixel imaging. Further, we successfully illustrate an implementation of compressed sensing for image reconstruction in conditions of high noise. In combination, this robust technique could be applied to any spectral region where spatial light phase modulators or phased-array sources are available.

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Transplantation: current developments and future directions; The future of clinical islet transplantation as a cure for diabetes

Frontiers in Bioscience ◽

10.2741/2755 ◽

2008 ◽

Vol 13 (13) ◽

pp. 1192 ◽

Cited By ~ 43

Author(s):

Anthony Hogan

Keyword(s):

Islet Transplantation ◽

Future Directions ◽

Clinical Islet Transplantation ◽

The Future

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The prototypes of nanozyme-based nanorobots

Biophysics Reports ◽

10.1007/s41048-020-00125-8 ◽

2020 ◽

Vol 6 (6) ◽

pp. 223-244

Author(s):

Jiaying Xie ◽

Yiliang Jin ◽

Kelong Fan ◽

Xiyun Yan

Keyword(s):

Functional Nanomaterials ◽

Promising Candidate ◽

Future Directions ◽

Complex Tasks ◽

Logic Control ◽

The Future ◽

Flexible Designs

AbstractArtificial nanorobot is a type of robots designed for executing complex tasks at nanoscale. The nanorobot system is typically consisted of four systems, including logic control, driving, sensing and functioning. Considering the subtle structure and complex functionality of nanorobot, the manufacture of nanorobots requires designable, controllable and multi-functional nanomaterials. Here, we propose that nanozyme is a promising candidate for fabricating nanorobots due to its unique properties, including flexible designs, controllable enzyme-like activities, and nano-sized physicochemical characters. Nanozymes may participate in one system or even combine several systems of nanorobots. In this review, we summarize the advances on nanozyme-based systems for fabricating nanorobots, and prospect the future directions of nanozyme for constructing nanorobots. We hope that the unique properties of nanozymes will provide novel ideas for designing and fabricating nanorobotics.

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Population screening for glaucoma in UK: current recommendations and future directions

Eye ◽

10.1038/s41433-021-01687-8 ◽

2021 ◽

Author(s):

Sana Hamid ◽

Parul Desai ◽

Pirro Hysi ◽

Jennifer M. Burr ◽

Anthony P. Khawaja

Keyword(s):

Screening Test ◽

Vision Loss ◽

Open Angle Glaucoma ◽

Public Awareness ◽

Population Based ◽

Population Screening ◽

Effective Population ◽

Future Directions ◽

The Future ◽

The Uk

AbstractEffective population screening for glaucoma would enable earlier diagnosis and prevention of irreversible vision loss. The UK National Screening Committee (NSC) recently published a review that examined the viability, effectiveness and appropriateness of a population-based screening programme for primary open-angle glaucoma (POAG). In our article, we summarise the results of the review and discuss some future directions that may enable effective population screening for glaucoma in the future. Two key questions were addressed by the UK NSC review; is there a valid, accurate screening test for POAG, and does evidence exist that screening reduces morbidity from POAG compared with standard care. Six new studies were identified since the previous 2015 review. The review concluded that screening for glaucoma in adults is not recommended because there is no clear evidence for a sufficiently accurate screening test or for better outcomes with screening compared to current care. The next UK NSC review is due to be conducted in 2023. One challenge for POAG screening is that the relatively low disease prevalence results in too many false-positive referrals, even with an accurate test. In the future, targeted screening of a population subset with a higher prevalence of glaucoma may be effective. Recent developments in POAG polygenic risk prediction and deep learning image analysis offer potential avenues to identifying glaucoma-enriched sub-populations. Until such time, opportunistic case finding through General Ophthalmic Services remains the primary route for identification of glaucoma in the UK and greater public awareness of the service would be of benefit.

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Diffraction Efficiency Characteristics for MEMS-Based Phase-Only Spatial Light Modulator with Nonlinear Phase Distribution

Photonics ◽

10.3390/photonics8030062 ◽

2021 ◽

Vol 8 (3) ◽

pp. 62

Author(s):

Remington S. Ketchum ◽

Pierre-Alexandre Blanche

Keyword(s):

Diffraction Efficiency ◽

High Speed ◽

Phase Distribution ◽

Complex Structure ◽

Spatial Light Modulators ◽

Light Modulator ◽

Micro Electro Mechanical Systems ◽

Light Modulators ◽

Nonlinear Phase ◽

Liquid Crystal On Silicon

Micro-electro mechanical systems (MEMS)-based phase-only spatial light modulators (PLMs) have the potential to overcome the limited speed of liquid crystal on silicon (LCoS) spatial light modulators (SLMs) and operate at speeds faster than 10 kHz. This expands the practicality of PLMs to several applications, including communications, sensing, and high-speed displays. The complex structure and fabrication requirements for large, 2D MEMS arrays with vertical actuation have kept MEMS-based PLMs out of the market in favor of LCoS SLMs. Recently, Texas Instruments has adapted its existing DMD technology for fabricating MEMS-based PLMs. Here, we characterize the diffraction efficiency for one of these PLMs and examine the effect of a nonlinear distribution of addressable phase states across a range of wavelengths and illumination angles.

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On imaging, speed, and the future of lymphocyte signaling

Journal of Experimental Medicine ◽

10.1084/jem.20050223 ◽

2005 ◽

Vol 201 (4) ◽

pp. 505-508 ◽

Cited By ~ 4

Author(s):

Alexander Tarakhovsky

Keyword(s):

Imaging Techniques ◽

Roundtable Discussion ◽

Advanced Imaging ◽

The Future ◽

Personal Perspectives ◽

Imaging Speed

During a recent roundtable discussion, we captured some personal perspectives on the new insight that advanced imaging techniques promise to bring to the study of lymphocyte signaling. The experts present their views on the power of imaging, the problems that need to be overcome, and the potential of the technology.

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The Social Robot in Rehabilitation and Assistance: What is the Future?

Healthcare ◽

10.3390/healthcare9030244 ◽

2021 ◽

Vol 9 (3) ◽

pp. 244

Author(s):

Daniele Giansanti

Keyword(s):

The Elderly ◽

Social Robots ◽

Social Robot ◽

Clinical Use ◽

Research Development ◽

Future Directions ◽

Collaborative Robotics ◽

Research Perspectives ◽

The Social ◽

The Future

This commentary aims to address the field of social robots both in terms of the global situation and research perspectives. It has four polarities. First, it revisits the evolutions in robotics, which, starting from collaborative robotics, has led to the diffusion of social robots. Second, it illustrates the main fields in the employment of social robots in rehabilitation and assistance in the elderly and handicapped and in further emerging sectors. Third, it takes a look at the future directions of the research development both in terms of clinical and technological aspects. Fourth, it discusses the opportunities and limits, starting from the development and clinical use of social robots during the COVID-19 pandemic to the increase of ethical discussion on their use.

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Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

Science ◽

10.1126/science.aaw6747 ◽

2019 ◽

Vol 364 (6445) ◽

pp. 1087-1090 ◽

Cited By ~ 64

Author(s):

Shi-Qiang Li ◽

Xuewu Xu ◽

Rasna Maruthiyodan Veetil ◽

Vytautas Valuckas ◽

Ramón Paniagua-Domínguez ◽

...

Keyword(s):

High Resolution ◽

Spatial Light Modulator ◽

Deflection Angle ◽

Beam Steering ◽

Beam Deflection ◽

Spatial Light Modulators ◽

Light Modulator ◽

Steering Angle ◽

Holographic Display ◽

Light Modulators

Rapidly developing augmented reality, solid-state light detection and ranging (LIDAR), and holographic display technologies require spatial light modulators (SLMs) with high resolution and viewing angle to satisfy increasing customer demands. Performance of currently available SLMs is limited by their large pixel sizes on the order of several micrometers. Here, we propose a concept of tunable dielectric metasurfaces modulated by liquid crystal, which can provide abrupt phase change, thus enabling pixel-size miniaturization. We present a metasurface-based transmissive SLM, configured to generate active beam steering with >35% efficiency and a large beam deflection angle of 11°. The high resolution and steering angle obtained provide opportunities to develop the next generation of LIDAR and display technologies.

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