Real-time contrast-enhanced holographic imaging using phase coherent photorefractive quantum wells

Dongol, A.; Thompson, Jonathan; Schmitzer, Heidrun; Tierney, D.; Wägner, Hans

doi:10.1364/oe.23.012795

Cited by 3 publications

(2 citation statements)

References 34 publications

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“…Alternative forms of nonlinearity, such as photochromic 27 , 28 and photorefractive 29 – 31 effects, may also be used, but these processes are typically slow, involving response time scales on the order of a few 27 , 29 to tens of seconds 31 . Other forms of photorefractive effect, for example, in multiple quantum wells, are fast but present very weak nonlinearity 32 – 34 . Some organic photorefractive devices show millisecond responses, but rely on coherent interference to build up spatial charge patterns and create strong nonlinear diffraction patterns, and are thus mostly adapted to holography 35 , 36 .…”

Section: Introductionmentioning

confidence: 99%

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Zhang,

Xu,

et al. 2024

Nat Commun

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Nonlinear optical processing of ambient natural light is highly desired for computational imaging and sensing. Strong optical nonlinear response under weak broadband incoherent light is essential for this purpose. By merging 2D transparent phototransistors (TPTs) with liquid crystal (LC) modulators, we create an optoelectronic neuron array that allows self-amplitude modulation of spatially incoherent light, achieving a large nonlinear contrast over a broad spectrum at orders-of-magnitude lower intensity than achievable in most optical nonlinear materials. We fabricated a 10,000-pixel array of optoelectronic neurons, and experimentally demonstrated an intelligent imaging system that instantly attenuates intense glares while retaining the weaker-intensity objects captured by a cellphone camera. This intelligent glare-reduction is important for various imaging applications, including autonomous driving, machine vision, and security cameras. The rapid nonlinear processing of incoherent broadband light might also find applications in optical computing, where nonlinear activation functions for ambient light conditions are highly sought.

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Section: Introductionmentioning

confidence: 99%

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Zhang,

Xu,

et al. 2024

Nat Commun

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show abstract

“…effect, for example, in multiple quantum wells, are fast but present very weak nonlinearity [32][33][34] . Some organic photorefractive devices show millisecond responses, but rely on coherent interference to build up spatial charge patterns and create strong nonlinear diffraction patterns, and are thus mostly adapted to holography 35,36 .…”

mentioning

confidence: 99%

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Duan,

Zhang,

et al. 2024

Preprint

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Nonlinear optical processing of ambient natural light is highly desired for computational imaging and sensing. Strong optical nonlinear response under weak broadband incoherent light is essential for this purpose. By merging 2D transparent phototransistors (TPTs) with liquid crystal (LC) modulators, we create an optoelectronic neuron array that allows self-amplitude modulation of spatially incoherent light, achieving a large nonlinear contrast over a broad spectrum at orders-of-magnitude lower intensity than achievable in most optical nonlinear materials. We fabricated a 10,000-pixel array of optoelectronic neurons, and experimentally demonstrated an intelligent imaging system that instantlyattenuates input glares while retaining the weaker-intensity objects captured by a cellphone camera. This intelligent glare-reduction is important for various imaging applications, including autonomous driving, machine vision, and security cameras. The rapid nonlinear processing of incoherent broadband light might also find applications in optical computing, where nonlinear activation functions for ambient light conditions are highly sought.

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Nonlinear encoding in diffractive information processing using linear optical materials

Li,

Ozcan

2024

Light Sci Appl

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Nonlinear encoding of optical information can be achieved using various forms of data representation. Here, we analyze the performances of different nonlinear information encoding strategies that can be employed in diffractive optical processors based on linear materials and shed light on their utility and performance gaps compared to the state-of-the-art digital deep neural networks. For a comprehensive evaluation, we used different datasets to compare the statistical inference performance of simpler-to-implement nonlinear encoding strategies that involve, e.g., phase encoding, against data repetition-based nonlinear encoding strategies. We show that data repetition within a diffractive volume (e.g., through an optical cavity or cascaded introduction of the input data) causes the loss of the universal linear transformation capability of a diffractive optical processor. Therefore, data repetition-based diffractive blocks cannot provide optical analogs to fully connected or convolutional layers commonly employed in digital neural networks. However, they can still be effectively trained for specific inference tasks and achieve enhanced accuracy, benefiting from the nonlinear encoding of the input information. Our results also reveal that phase encoding of input information without data repetition provides a simpler nonlinear encoding strategy with comparable statistical inference accuracy to data repetition-based diffractive processors. Our analyses and conclusions would be of broad interest to explore the push-pull relationship between linear material-based diffractive optical systems and nonlinear encoding strategies in visual information processors.

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Real-time contrast-enhanced holographic imaging using phase coherent photorefractive quantum wells

Cited by 3 publications

References 34 publications

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Nonlinear encoding in diffractive information processing using linear optical materials

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