Terahertz compressive imaging with metamaterial spatial light modulators

Watts, Claire M.; Shrekenhamer, David; Montoya, John; Lipworth, Guy; Hunt, John; Sleasman, Timothy; Krishna, S.; Smith, David R.; Padilla, Willie J.

doi:10.1038/nphoton.2014.139

Cited by 730 publications

(401 citation statements)

References 18 publications

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“…Application of reverse voltage bias enables tuning the frequency of the resonant absorption, with modulation speeds up to 10 MHz. This type of metamaterial absorber based THz spatial modulator, shown in figure 27(e), has been recently successfully em- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 ployed in THz compressive imaging [182].…”

Section: Page 39 Of 59mentioning

confidence: 99%

A review of metasurfaces: physics and applications

2016

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Abstract. Metamaterials are composed of periodic subwavelength metal/dielectric structures that resonantly couple to the electric and/or magnetic components of the incident electromagnetic fields, exhibiting properties that not found in nature. This class of micro-and nano-structured artificial media have attracted great interest during the past 15 years and yielded ground-breaking electromagnetic and photonic phenomena. However, the high losses and strong dispersion associated with the resonant responses and the use of metallic structures, as well as the difficulty in fabricating the micro-and nanoscale 3D structures, have hindered practical applications of metamaterials. Planar metamaterials with subwavelength thickness, or metasurfaces, consisting of single-layer or few-layer stacks of planar structures can be readily fabricated using lithography and nanoprinting methods, and the ultrathin thickness in the wave propagation direction can greatly suppress the undesirable losses. Metasurfaces enable a spatially varying optical response (e.g., scattering amplitude, phase, and polarization), mold optical wavefronts into shapes that can be designed at will, and facilitate the integration of functional materials to accomplish active control and greatly enhanced nonlinear response. This paper reviews recent progress in the physics of metasurfaces operating at wavelengths ranging from microwave to visible. We provide an overview of key metasurface concepts such as anomalous reflection and refraction, and introduce metasurfaces based on the PancharatnamBerry phase and Huygens' metasurfaces, as well as their use in wavefront shaping and beam forming applications, followed by a discussion of polarization conversion in fewlayer metasurfaces and their related properties. An overview of dielectric metasurfaces reveals their ability to realize unique functionalities coupled with Mie resonances and their low ohmic losses. We also describe metasurfaces for wave guidance and radiation control, as well as active and nonlinear metasurfaces. Finally, we conclude by providing our opinions of future developments in this rapidly developing research field.

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Section: Page 39 Of 59mentioning

confidence: 99%

A review of metasurfaces: physics and applications

2016

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“…Equation (1) is, in fact, the Hadamard transformation of the object onto the Hadamard frequency space. The object is then recovered by the inverse transformation 1 …”

Section: Single-pixel 3d Imaging By Using a Color Led Displaymentioning

confidence: 99%

“…Some other imaging techniques can benefit from light detectors with no spatial structure. This is the case of imaging with low light levels or with electromagnetic radiation in spectral ranges out of the visible region, particularly in the near IR and terahertz spectral bands, where it is more difficult to make a pixelated sensor [1][2][3]. Imaging with single-pixel detectors can be useful also when the purpose is to measure the spatial distribution of several optical parameters of the light beam simultaneously, not only the intensity but also the polarization state [4], the phase [5,6], the color [7][8][9][10], or the spectral content [11][12][13][14][15][16] Single-pixel imaging techniques [25,26] are based on illuminating the scene with a sequence of light structured patterns while the light reflected or transmitted by the objects is recorded by a single photosensor such as a photodiode or photomultiplier tube (PMT).…”

Section: Introductionmentioning

confidence: 99%

Low-cost single-pixel 3D imaging by using an LED array

Salvador-Balaguer¹,

Carmona²,

Chabert³

et al. 2018

Opt. Express

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Abstract:We propose a method to perform color imaging with a single photodiode by using light structured illumination generated with a low-cost color LED array. The LED array is used to generate a sequence of color Hadamard patterns which are projected onto the object by a simple optical system while the photodiode records the light intensity. A field programmable gate array (FPGA) controls the LED panel allowing us to obtain high refresh rates up to 10 kHz. The system is extended to 3D imaging by simply adding a low number of photodiodes at different locations. The 3D shape of the object is obtained by using a noncalibrated photometric stereo technique. Experimental results are provided for an LED array with 32 × 32 elements.

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“…Recent research has demonstrated THz SLMs using all-electronic dynamic metamaterials used in single-pixel THz imaging systems. 10,15,16 These dynamic metamaterial SLMs are electronically controlled by injecting charges or depleting them in the bulk semiconductor substrate, which is an inherently slow process due to the intrinsically large capacitance of what is essentially a large bulk diode structure. 15,17,18 This results in a slow switching speed and large dynamic power consumption.…”

Section: Introductionmentioning

confidence: 99%

A low-voltage high-speed terahertz spatial light modulator using active metamaterial

Rout

Sonkusale

2016

APL Photonics

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An all solid-state metamaterial based terahertz (THz) spatial light modulator (SLM) is presented which uses high mobility 2DEG to manipulate the metamaterial resonant frequency (0.45 THz) leading to terahertz wave modulation. The 2DEG is created by embedding pseudomorphic high-electron mobility transistors in the capacitive gap of each electrical-LC resonator, allowing the charge density to be controlled with very low voltage (1 V) and modulating speeds up to 10 MHz while consuming sub-milliwatt power. We have demonstrated our SLM as a 2 × 2 pixel array operating around 0.45 THz by raster scanning a 6 × 6 image of an occluded metal object behind a thick polystyrene screen using a single-pixel THz imaging setup.

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Terahertz compressive imaging with metamaterial spatial light modulators

Cited by 730 publications

References 18 publications

A review of metasurfaces: physics and applications

A review of metasurfaces: physics and applications

Low-cost single-pixel 3D imaging by using an LED array

A low-voltage high-speed terahertz spatial light modulator using active metamaterial

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