Biomimetic optics: visual systems Lakshminarayanan, Vasudevan; Kuppuswamy Parthasarathy, Mohana
Journal of modern optics,
09/2023, Letnik:
70, Številka:
13-15
Journal Article
Recenzirano
Biomimetics is the transfer of ideas and concepts borrowed from nature in order to develop solutions to technological issues. Research in biomimetic vision as a whole has focused on several aspects ...ranging from development of optical devices and sensors, innovative solutions to visual problems and building intelligent systems, all based on findings from nature. In this review, we discuss the diversity of animal eyes, optical systems inspired by natural eyes and their optical properties in nature that has the potential for biomimicry.
Compound eyes are natural multiaperture optical imaging systems and have substantial potential in the field of modern optics. However, both natural and artificial compound eyes are composed of ...ommatidia with fixed focal lengths, and thus incapable of variable‐focus imaging. In this study, inspired by the tunable crystalline lens of human eyes, smart stimuli‐responsive compound eyes based on the bovine serum album (BSA) protein are fabricated via femtosecond laser direct writing. Due to the swelling and shrinking effect of BSA under different pH conditions, a tunable field of view (FOV, 35°–80°) and variable focal length of ommatidia are achieved. In addition to the direct prototyping of an entire protein‐based compound eye, the ability to flexibly integrate the smart protein ommatidia with a conventional optical lens (an SU‐8 lens in this study) to form a composite compound eye is shown. The composite compound eye achieves nearly 400% of focal length tuning at a fixed FOV. It is anticipated that femtosecond laser fabrication and the integration of smart protein‐based compound eyes may emerge as an enabler for fabricating miniature tunable imaging systems.
Smart artificial compound eyes with the combined advantages of both insect compound eyes and human eyes are fabricated based on a pH‐responsive protein via femtosecond laser direct writing, demonstrating variable fields of view and focal lengths for tunable imaging. In addition to direct prototyping of entire compound eyes, flexible integration of tunable ommatidia with given micro‐optical components is realized.
With high thermal and mechanical stability, glass artificial compound eyes have great potential applications in wide field‐of‐view (FOV) imaging and fast detection. However, the rapid fabrication of ...large‐area, high integration, uniform, and well‐designed three‐dimensional (3D) glass compound eyes is still a great challenge. Here, a dry‐etching‐assisted femtosecond laser machining (DE‐FsLM) technology is proposed for fabrication of cm‐sized concave compound eye from a curved sapphire substrate, with which the fabrication efficiency can be improved by over two orders of magnitude compared with direct laser ablation. With high hardness and thermal stabilities, the sapphire concave compound eyes can be used as high‐temperature and hard‐casting templates for the replication of convex compound eyes on K9 glass. The replicated cm2‐size all‐glass compound eye consists of a spherical macrolens (1 cm diameter and 2.3 mm height) and over 190 000 close‐packed ommatidia (≈20 µm diameter and 1.5 µm height). The compound eyes exhibit excellent optical properties with wide FOV (up to 90°) imaging and focusing. These results indicate that the DE‐FsLM and casting replication technology will open new opportunities in micro‐/nanofabrication of hard materials.
Dry‐etching‐assisted femtosecond laser machining is proposed for the rapid fabrication of large‐scale uniform and smooth sapphire concave compound eye templates. K9 glass compound eyes are fabricated by high‐temperature casting replication from the sapphire concave compound eyes, which exhibit a wide field‐of‐view (up to 90°) for practical applications.
The natural compound eye is a striking imaging device with a wealth of fascinating optical features such as a wide field of view (FOV), low aberration, and high sensitivity. Dragonflies in particular ...possess large, sophisticated compound eyes that exhibit high resolving power and information‐processing capacity. Here, a large‐scale artificial compound eye inspired by the unique designs of natural counterparts is presented. The artificial compound eye is created by a high‐efficiency strategy that combines single‐pulse femtosecond laser wet etching with thermal embossing. These eyes have a macrobase diameter of 5 mm and ≈30 000 close‐packed ommatidia with an average diameter of 24.5 μm. Moreover, the optical properties of the artificial compound eyes are investigated; the results confirm that the eye demonstrates advanced imaging quality, an exceptionally wide FOV of up to 140°, and low aberration.
A large‐scale artificial compound eye, with a total of 30 000 ommatidia, is successfully fabricated by a high‐efficiency strategy that combines single‐pulse femtosecond laser wet etching with thermal embossing. The optical properties of the artificial compound eyes are investigated; the results confirm that the eye demonstrates comparable imaging quality, an exceptionally wide FOV of up to 140°, and low aberration.
Most animals that have compound eyes determine object distances by using monocular cues, especially motion parallax. In artificial compound eye imaging systems inspired by natural compound eyes, ...object depths are typically estimated by measuring optic flow; however, this requires mechanical movement of the compound eyes or additional acquisition time. In this paper, we propose a method for estimating object depths in a monocular compound eye imaging system based on the computational compound eye (COMPU-EYE) framework. In the COMPU-EYE system, acceptance angles are considerably larger than interommatidial angles, causing overlap between the ommatidial receptive fields. In the proposed depth estimation technique, the disparities between these receptive fields are used to determine object distances. We demonstrate that the proposed depth estimation technique can estimate the distances of multiple objects.
Light is the most important Zeitgeber for entraining animal activity rhythms to the 24-h day. In all animals, the eyes are the main visual organs that are not only responsible for motion and colour ...(image) vision, but also transfer light information to the circadian clock in the brain. The way in which light entrains the circadian clock appears, however, variable in different species. As do vertebrates, insects possess extraretinal photoreceptors in addition to their eyes (and ocelli) that are sometimes located close to (underneath) the eyes, but sometimes even in the central brain. These extraretinal photoreceptors contribute to entrainment of their circadian clocks to different degrees. The fruit fly
Drosophila melanogaster
is special, because it expresses the blue light-sensitive cryptochrome (CRY) directly in its circadian clock neurons, and CRY is usually regarded as the fly’s main circadian photoreceptor. Nevertheless, recent studies show that the retinal and extraretinal eyes transfer light information to almost every clock neuron and that the eyes are similarly important for entraining the fly’s activity rhythm as in other insects, or more generally spoken in other animals. Here, I compare the light input pathways between selected insect species with a focus on
Drosophila’s
special case.
The circadian clock is a timekeeper but also helps adapt physiology to the outside world. This is because an essential feature of clocks is their ability to adjust (entrain) to the environment, with ...light being the most important signal. Whereas cryptochrome-mediated entrainment is well understood in Drosophila, integration of light information via the visual system lacks a neuronal or molecular mechanism. Here, we show that a single photoreceptor subtype is essential for long-day adaptation. These cells activate key circadian neurons, namely the large ventral-lateral neurons (lLNvs), which release the neuropeptide pigment-dispersing factor (PDF). RNAi and rescue experiments show that PDF from these cells is necessary and sufficient for delaying the timing of the evening (E) activity in long-day conditions. This contrasts to PDF that derives from the small ventral-lateral neurons (sLNvs), which are essential for constant darkness (DD) rhythmicity. Using a cell-specific CRISPR/Cas9 assay, we show that lLNv-derived PDF directly interacts with neurons important for E activity timing. Interestingly, this pathway is specific for long-day adaptation and appears to be dispensable in equinox or DD conditions. The results therefore indicate that external cues cause a rearrangement of neuronal hierarchy, which contributes to behavioral plasticity.
•Receptor cell 8 of the compound eyes is essential for long-day adaptation•PDF from the lLNvs is necessary and sufficient for long-day adaptation•Disruption of the PDF receptor suggests a direct connection between lLNvs and LNds•The targets of PDF neurons change depending on environmental conditions
Schlichting et al. describe the contribution of a single photoreceptor subtype to long-day adaptation in Drosophila melanogaster. Light information from this receptor is integrated into the clock network by PDF release from the lLNvs, suggesting a shift of neuronal dominance in the network, depending on environmental conditions.
In article number 1903340, Yong‐Lai Zhang, Hong‐Bo Sun, and co‐workers fabricate smart artificial compound eyes with the combined advantages of both insect compound eyes and human eyes based on a ...pH‐responsive bovine serum album protein via a femtosecond laser direct writing method, demonstrating variable fields of view and focal lengths for tunable imaging.
Abstract
Crepuscular bees have larger compound eyes, ommatidia and ocelli than diurnal bees. These visual adaptations allow these bees to forage during twilight. While the sizes of visual organs are ...positively correlated with body size in diurnal bees, this relationship is as yet unclear in crepuscular bees. Here we measured the sizes of the ocellus; compound eyes; ommatidial density; and dorsal, frontal and ventral facets of 11 phylogenetically related bee species with different temporal patterns. We tested whether and how each of these visual attributes is correlated with body size and/or temporal pattern. Except for ommatidial density and size of the frontal ommatidia, which are similar in crepuscular bees of different sizes, we found that all other visual variables in diurnal and crepuscular bees are correlated with both body size and temporal pattern. The lower variability in ommatidial density among crepuscular bees suggests that their eyes operate on the threshold between light sensitivity and visual acuity. Furthermore, similar frontal ommatidial sizes in bees of different sizes indicate that this eye region is under higher evolutionary pressure in small than in large crepuscular bees to ensure light sensitivity. Finally, those crepuscular bees from different families convergently share the same visual characteristics.
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