Red Illumination Research Articles

Colour category constancy and the development of colour naming

In this study, we investigated the processes of coordination, adaptation, and calibration during the development of colour naming and colour constancy, and we tested whether colour term knowledge is related to colour constancy. We measured category membership and prototypes with 163 Munsell chips in preschool children (3- to 4-year-old) under neutral, green, and red illuminations, and compared their results to those of adults. We introduced an index of colour term maturity based on the similarity of children’s colour term use to adults, and a colour category constancy index that quantifies the variation in colour categorisation that is specific to illumination changes. Results showed that illumination changes affected children’s consistency of colour categorisation, but only to a small extent. However, colour term maturity and illumination-specific effects on consistency strongly varied in this age range. Correlations between colour term maturity and illumination-specific consistency indicated that colour constancy increases with colour term acquisition; but those results depended on the type of illumination changes (between neutral, green, and red). Together, our findings suggest that children progressively fine-tune and recalibrate the meaning of colour terms through processes of coordination and adaptation that are also involved in the calibration of colour constancy.

Can Acropora tenuis larvae attract native Symbiodiniaceae cells by green fluorescence at the initial establishment of symbiosis?

Most corals acquire symbiodiniacean symbionts from the surrounding environment to initiate symbiosis. The cell densities of Symbiodiniaceae in the environment are usually low, and mechanisms may exist by which new coral generations attract suitable endosymbionts. Phototaxis of suitable symbiodiniacean cells toward green fluorescence in corals has been proposed as one such mechanism. In the present study, we observed the phototaxis action wavelength of various strains of Symbiodiniaceae and the fluorescence spectra of aposymbiotic Acropora tenuis larvae at the time of endosymbiont uptake. The phototaxis patterns varied among the Symbiodiniaceae species and "native" endosymbionts-commonly found in Acropora juveniles present in natural environments; that is, Symbiodinium microadriaticum was attracted to blue light rather than to green light. Another native endosymbiont, Durusdinium trenchii, showed no phototaxis specific to any wavelength. Although the larvae exhibited green and broad orange fluorescence under blue-violet excitation light, the maximum green fluorescence peak did not coincide with that of the phototaxis action spectrum of S. microadriaticum. Rather, around the peak wavelength of larval green fluorescence, this native endosymbiont showed slightly negative phototaxis, suggesting that the green fluorescence of A. tenuis larvae may not play a role in the initial attraction of native endosymbionts. Conversely, broad blue larval fluorescence under UV-A excitation covered the maximum phototaxis action wavelength of S. microadriaticum. We also conducted infection tests using native endosymbionts and aposymbiotic larvae under red LED light that does not excite visible larval fluorescence. Almost all larvae failed to acquire S. microadriaticum cells, whereas D. trenchii cells were acquired by larvae even under red illumination. Thus, attraction mechanisms other than visible fluorescence might exist, at least in the case of D. trenchii. Our results suggest that further investigation and discussion, not limited to green fluorescence, would be required to elucidate the initial attraction mechanisms.

Rapid changes in spectral composition after darkness influences nitric oxide, glucose and hydrogen peroxide production in the Antarctic diatom Fragilariopsis cylindrus

Ice-associated phototrophic taxa contribute significantly to Antarctic primary production and are crucial to ecosystem stability in the Southern Ocean. The quantity and quality of light required for photosynthesis is the single most influential driver of ice-associated algal communities. While the presence of ice and snow greatly reduces the irradiance reaching the ice-water interface, it is also the spectral quality that influences the phototrophy of ice-associated microalgae communities. Here we test the capability of three electrochemical microsensors to detect photosynthetically derived “stress” metabolites produced by the Antarctic diatom F. cylindrus. Following a period of dark incubation, this photo-physiological response differed with respect to the intensity and spectral quality of light during re-illumination. Exposure to blue light resulted in impairment in photosynthetic efficiency of PSII (Fv/Fm) and resulted in the production of nitric oxide (NO), hydrogen peroxide (H2O2) and glucose exudation. A similar trend in metabolite production was observed when subjected to white light, but not during red or green illumination. These results indicate that rapid exposure to light and variation in spectral composition can cause significant stress that can be quantified using H2O2, NO and glucose microsensors. This metabolic overflow was triggered by the disruption of normal photosynthetic electron flow and it is proposed that the detection of extracellular metabolites can be directly attributed to intracellular activity.

Documenting nocturnal activity of dragon-headed katydids (Lesina blanchardi) under artificial light.

Across the genera of katydids from the family Tettigoniidae, both diurnal and nocturnal species have been identified. The Saint Louis Zoo Bayer Insectarium filmed dragon-headed katydids (Lesina blanchardi) overnight using red light-emitting diodes (LEDs) to examine the activity of this presumed nocturnal species to provide quantitative information about these insects that are otherwise immobile when keepers are present. Evidence from the literature suggests that LED bulbs emitting long-wavelength red and infrared lights are less likely to cause changes to the subjects' behavioral budgets and movements through the habitat. Three katydids were filmed for 5 nights, and time-interval scan sampling was used to record their positions and whether they were active every 15 min for two 2-hperiods starting at midnight and noon. A modified Shannon's diversity index determined that katydids were recorded in more areas when under only red LEDs at night as compared to artificial daytime working lights. Similarly, repeated measures analysis of variance indicated that insects were significantly more active under nighttime red LEDs when compared to daytime working lights. While we cannot be sure if behaviors recorded under red LEDs are the same as those that would be performed under total darkness in situ, the use of red LED illumination ex situ to facilitate overnight filming did not suppress nocturnal movement or activity for our subjects.

Chlorophyll fluorescence kinetics and oxygen evolution in Chlorella vulgaris cells: Blue vs. red light

Oxygen evolution and chlorophyll fluorescence kinetics in cells of the Chlorella vulgaris strain (Europolytest, Russia) were studied under low, moderate and high photosynthetic photon flux densities (PPFD 40, 130 and 350 μmol photons m–2 s–1) of the red and blue actinic light. A novel method of a pulse amplitude modulated (PAM) Fourier chlorophyll fluorometry was applied to obtain photoinduction curves simultaneously for the red and blue measuring light for one sample. It was found that the red light did not induce oxygen evolution at low and moderate PPFD, whereas at high PPFD it caused a declining oxygen release. There was only a trace fluorescence kinetics at the low PPFD, but noticeable fluorescence kinetics under the red light was observed at the low and moderate PPFD. Particularly, the moderate red illumination of Chlorella cells excited a high chlorophyll fluorescence kinetics along with the absence of oxygen evolution that suggests anoxygenic photosynthesis. In contrast, the blue light induced a significant oxygen evolution as well as fluorescence kinetics already at low PPFD which were both further increased with the PPFD increasing. In addition, a high value of the chromatic divergence of quantum yield of photosystem II was revealed between the red and blue measuring light under high PPFD of the red actinic light.

LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.

Visual acuity assessment in phakic and pseudophakic eyes under red, green, and blue illumination

espanolProposito: Valorar el impacto de la iluminacion cuasi-monocromatica en la agudeza visual (AV) en ojos faquicos y pseudofaquicos utilizando diferentes longitudes de onda. Metodo: El trabajo se realizo con 61 ojos clasificados en dos grupos: 31 faquicos jovenes y 30 pseudofaquicos implantados con una lente intraocular acrilica monofocal. La AV lejana fue medida usando un optotipo expresamente disenado para el trabajo iluminandolo secuencialmente con tres luces LED de longitud de onda nominal de (B) 455nm, (G) 530nm, (R) 625nm y blanca (W) (CCT= 6500K). Adicionalmente se midio la AV cercana usando las mismas iluminaciones en el grupo de jovenes faquicos. Resultados: La mejor AV lejana en ojos faquicos se obtuvo con las iluminaciones roja y blanca mientras que en el grupo de pseudofaquicos esta se obtuvo con las iluminaciones verde y blanca. La AV con iluminacion azul fue la que obtuvo peores resultados en ambos grupos. No se encontraron diferencias estadisticamente significativas en la AV cercana para las iluminaciones R, G y B, pero fue significativamente mejor con iluminacion W que con iluminacion B. Conclusion: Los valores de AV lejana revelan el impacto de la diferencia cromatica de refracion (CDRx) provocada por la aberracion cromatica longitudinal de los ojos evaluados. Con iluminacion roja, la capacidad acomodativa de los ojos jovenes faquicos compensa la aberracion. En ojos pseudofaquicos, se observa una disminucion natural de la AV. En estos casos, ademas, la perdida de la acomodacion y un resultado refractivo postoperatorio calculado para una longitud de onda de diseno verde, hacen que la AV obtenida con luz verde sea igual a la obtenida con luz blanca. La AV cercana media obtenida en ojos faquicos jovenes revela un equilibrio en la capacidad de acomodacion con iluminacion R, G y B, si bien la AV cercana es significativamente superior con luz blanca que con luz azul. EnglishPurpose: To assess the impact of the quasi-monochromatic illumination on visual acuity (VA) in phakic and monofocal pseudophakic eyes using different wavelengths. Methods: Sixty-one eyes classified in two groups (phakic and pseudophakic) participated in this study: 31 young phakic and 30 pseudophakic implanted with an acrylic monofocal intraocular lens. Distance VA was measured with custom optotype illuminated sequentially with three LED lights of nominal wavelengths (B) 455nm, (G) 530nm, (R) 625nm and white (W) LED light (CCT= 6500K). Near VA was additionally assessed in young phakic eyes under the same illuminations. Results: Best mean distance VA was obtained under red and white lights in young phakic eyes, whereas it was obtained under white and green lights in pseudophakic eyes. For both groups, the blue illumination led to the worst mean distance VA outcomes. No significant differences were found among mean near VA for R, G an B lights, but it was significantly better under W light than under B light. Conclusion: The measured distance VA values reveal the impact of the chromatic difference of refraction caused by the longitudinal chromatic aberration of the tested eyes. This aberration, is compensated by the accommodation capability of young phakics under red light. In the case of monofocal elderly pseudophakic eyes, a natural age-related decrease in the VA is observed. Additionally, the lack of accommodation, and a postoperative refraction outcome likely targeted for a green design wavelength, make the mean distance VA under green light match the one under white light. The mean near VA results in young phakic subjects revealed a balanced accommodation capability to every R, G, B illumination, but significantly higher under W light than under B light.

Novel, automated, semi-industrial modular photobioreactor system for cultivation of demanding microalgae that produce fine chemicals—The next story of H. pluvialis and astaxanthin

Recently, there has been increased interest in the use of microorganisms in the production of pharmaceuticals, nutraceuticals and energy supply products, which is due to their rapid growth rate and ability to biosynthesize fine chemicals or biotransform specific xenobiotics. To achieve the desired scale of production and optimization of microbial cultures, it is necessary to design bioreactors that enable process automation, control of working parameters, reduction of microbial and chemical contaminations, and culture independence of climate conditions. In response to this need, an original, modular airlift-type photobioreactor system was designed and manufactured. This novel semitechnical system, with a total volume of 1000 dm3, was operated via computer control, which enabled the creation of time profiles of red, blue and white LED illumination and of carbon dioxide and air dosing. The quality and usefulness of the developed system was demonstrated via the case study, namely two-stage cultivation of the microalgae Haematococcus pluvialis—a species commonly used in the production of natural astaxanthin. The experimentally developed procedure ensures a repeatable and efficient biomass multiplication process and the maintenance of a light- and chemical-mediated effective stress mechanism that allows the production of up to 3.2% natural astaxanthin in terms of dry biomass.

Electroretinographic study of the magnetic compass in European robins.

Migratory birds are known to be sensitive to external magnetic field (MF). Much indirect evidence suggests that the avian magnetic compass is localized in the retina. Previously, we showed that changes in the MF direction could modulate retinal responses in pigeons. In the present study, we performed similar experiments using the traditional model animal to study the magnetic compass, European robins. The photoresponses of isolated retina were recorded using ex vivo electroretinography (ERG). Blue- and red-light stimuli were applied under an MF with the natural intensity and two MF directions, when the angle between the plane of the retina and the field lines was 0° and 90°, respectively. The results were separately analysed for four quadrants of the retina. A comparison of the amplitudes of the a- and b-waves of the ERG responses to blue stimuli under the two MF directions revealed a small but significant difference in a- but not b-waves, and in only one (nasal) quadrant of the retina. The amplitudes of both the a- and b-waves of the ERG responses to red stimuli did not show significant effects of the MF direction. Thus, changes in the external MF modulate the European robin retinal responses to blue flashes, but not to red flashes. This result is in a good agreement with behavioural data showing the successful orientation of birds in an MF under blue, but not under red illumination.

Virtual brightfield and fluorescence staining for Fourier ptychography via unsupervised deep learning.

Fourier ptychographic microscopy (FPM) is a computational approach geared towards creating high-resolution and large field-of-view images without mechanical scanning. Acquiring color images of histology slides often requires sequential acquisitions with red, green, and blue illuminations. The color reconstructions often suffer from coherent artifacts that are not presented in regular incoherent microscopy images. As a result, it remains a challenge to employ FPM for digital pathology applications, where resolution and color accuracy are of critical importance. Here we report a deep learning approach for performing unsupervised image-to-image translation of FPM reconstructions. A cycle-consistent adversarial network with multiscale structure similarity loss is trained to perform virtual brightfield and fluorescence staining of the recovered FPM images. In the training stage, we feed the network with two sets of unpaired images: (1) monochromatic FPM recovery and (2) color or fluorescence images captured using a regular microscope. In the inference stage, the network takes the FPM input and outputs a virtually stained image with reduced coherent artifacts and improved image quality. We test the approach on various samples with different staining protocols. High-quality color and fluorescence reconstructions validate its effectiveness.

CRISPR/Cas9 mediated disruption of the white gene leads to pigmentation deficiency and copulation failure in Drosophila suzukii

The Spotted-wing Drosophila (Drosophila suzukii) is a devastating invasive pest of fruit crops. In D. melanogaster, the white (w) gene was associated with pigmentation and mating behavior, which are also important aspects to understand the invasion biology as well as to develop control strategies for D. suzukii. Here, we show that the generation of D. suzukii white-eyed mutants by CRISPR/Cas9 mutagenesis of the w gene resulted in the complete failure of copulation when w− males were individually paired with w− females in small circular arenas (diameter 0.7 cm) for 24 h. Further analysis showed that the mating defect was associated with w− males and could not be rectified by two years of inbreeding by crossing sibling w− females with w+ males, dim red illumination, male–female sexual training, changing to large arenas (diameter 3.5 cm), or different sex ratios. Profound pigmentation deficiency was detected in the compound eyes, ocelli, Malpighian tubules and testis sheaths in the w− flies. Specifically, testis imaging showed that w− males failed to deposit any pigments into pigment cells of the testis sheath, and produced smaller sperms and less seminal fluid compared to those from wildtype males. Together these observations suggest that the w gene plays an essential role in the regulation of sexual behavior and reproduction in D. suzukii. The similarities and differences in w gene function between D. suzukii and D. melanogaster in the context of pigmentation and mating behavior are discussed.

Fabrication of bifacial sandwiched heterojunction photoconductor – Type and MAI passivated photodiode – Type perovskite photodetectors

Abstract In this work, we report novel heterojunctions perovskite photodetector architecture utilizing metal-free contact electrodes. The metal-free contact electrodes were exploited to fabricate photoconductor – type perovskite photodetector. The attempt to investigate the effect of passivating the active layers of the as – proposed architecture with electrolytic MAI gave rise to a photodiode – type perovskite photodetector. These two photodetector types are sensitive and responsive to light sources through their dual transparent electrodes faces (N-face and T-face). We also showed that passivating the surfaces of the sandwiched perovskite layers with MAI solution improves the performance of the fabricated photodetectors, where the detectivity is enhanced by a factor of hundred compared to non-passivated devices. The proposed photodetectors architectures demonstrate champion dual-detectivity (1.77 × 1014 Jones for N-face and 4.64 × 1014 Jones for T-face), dual-responsivity (1.94 × 103 A/W for N-face and 1.61 × 103 A/W for T-face) and high dual – sensitivity (3.3 × 102 for N-face and 1.1 × 102 for T-face). All these properties were obtained from the two faces of the MAI passivated photodetectors under 0.02 mW/cm2 red LED illumination and at −2.0 bias voltage. This novel architecture may scale up towards building energy and cost efficient classes of optoelectronic and photovoltaic devices which are responsive to light in two directions.

Giant photostriction of CaCu3Ti4O12 ceramics under visible light illumination

Ferroelectrics with a perovskite structure, exhibiting strong coupling between photons, carriers, and phonons, have been demonstrated to show a strong photostrictive response. Limited by the optical bandgap, most of the reported ferroelectric perovskites respond only to UV light or weakly respond to visible light below 550 nm. Herein, the photostrictive performance of CaCu3Ti4O12 (CCTO) ceramics, with a low bandgap of ∼1.5 eV (ideal for solar spectrum absorption), is comprehensively investigated. Although the compound presents no ferroelectricity, in general, a giant photostriction of ∼10−3 with a large photostrictive efficiency of ∼10−11 m3/W in CCTO ceramics is observed by applying purple (405 nm), green (520 nm), and red (655 nm) laser illumination. Evidenced by the XRD peak shifts under external laser illumination and the phonon mode shifts via the power-dependent Raman spectrum, the light-induced non-thermal deformation in CCTO is attributed to the enhanced stretching of O–Ti–O chains and the distortions of TiO6 octahedrons. The excellent and uniform photostrictive performance of CCTO ceramics in the visible-light region makes them potential candidates for practical applications in next-generation photo-driven electromechanical devices.

Automatic Phenotyping Test of Sunflower Seeds

Abstract The development of automated precision technologies for the phenotyping test of seeds by a complex of functional features in the selection process of sunflower is relevant and promising. The task of developing a device for the automatic phenotyping test of seeds and the algorithm for finding and isolating seeds based on color information was set. Research was conducted on a stand, which consisted of the following elements: Video Microscope Camera 1080 P 16MP HDMI USB manufactured by Eakins, a set of LEDs of three types (red, green, blue) and a personal computer. The results of experimental studies of the process of automatic phenotyping test of seeds of different sunflower varieties allowed us to establish an average error of determining the geometric dimensions of sunflower seeds (length L and width B) – 0.06 mm. The histograms of the color distribution of sunflower seeds in the RGB color space with different illumination are established. As a result of the analysis of the obtained histograms of the color distribution of sunflower seeds in the RGB color space it is established that in the case of color homogeneity, the discreteness of the channels with red illumination is most clearly seen. A device for automatic phenotyping test of seeds has been developed, which preserves the accuracy of individual measurement of the geometric dimensions of sunflower seeds, determining their shape and color, which corresponds to modern measuring tools, and provides low complexity and high technological implementation of the phenotyping test procedure (determination, ascertaining and identification) material, according to its morphological and marker features.

Self-Powered Visible-Invisible Multiband Detection and Imaging Achieved Using High-Performance 2D MoTe2/MoS2 Semivertical Heterojunction Photodiodes.

Two-dimensional(2D) van der Waals (vdW) heterostructures herald new opportunities for conducting fundamental studies of new physical/chemical phenomena and developing diverse nanodevice applications. In particular, vdW heterojunction p-n diodes exhibit great potential as high-performance photodetectors, which play a key role in many optoelectronic applications. Here, we report on 2D MoTe2/MoS2 multilayer semivertical vdW heterojunction p-n diodes and their optoelectronic application in self-powered visible-invisible multiband detection and imaging. Our MoTe2/MoS2 p-n diode exhibits an excellent electrical performance with an ideality factor of less than 1.5 and a high rectification (ON/OFF) ratio of more than 104. In addition, the photodiode exhibits broad spectral photodetection capability over the range from violet (405 nm) to near-infrared (1310 nm) wavelengths and a remarkable linear dynamic range of 130 dB within an optical power density range of 10-5 to 1 W/cm2 in the photovoltaic mode. Together with these favorable static photoresponses and electrical behaviors, very fast photo- and electrical switching behaviors are clearly observed with negligible changes at modulation frequencies greater than 100 kHz. In particular, inspired by the photoswitching results for periodic red (638 nm) and near-infrared (1310 nm) illumination at 100 kHz, we successfully demonstrate a prototype self-powered visible-invisible multiband image sensor based on the MoTe2/MoS2 p-n photodiode as a pixel. Our findings can pave the way for more advanced developments in optoelectronic systems based on 2D vdW heterostructures.

New results for aperiodic, clustered-dot halftoning

Spot colors are widely used in the food packaging industry. We wish to add a watermark signal within a spot color that is readable by a Point Of Sale (POS) barcode scanner which typically has red illumination. Some spot colors such as blue, black and green reflect very little red light and are difficult to modulate with a watermark at low visibility to a human observer. The visibility measurements that have been made with the Digimarc watermark enables the selection of a complementary color to the base color which can be detected by a POS barcode scanner but is imperceptible at normal viewing distance.

The effect of red illumination on the perceived temperature on the human body

The effect of red illumination on the perceived temperature on the human body

The Influence of Illumination Color on the Subjective Visual Recognition of Biological Specimens.

Visual examination by the naked eye is integral to medical diagnosis and surgery. The illumination in conditioned color is widely used for visual inspection in the industry but has not been introduced to the biomedical context. The color that can enhance the visual recognition of individual tissues is still unknown. Therefore, we carried out a visual recognition experiment on biological specimens to determine the subjective preference for illumination color based on questionnaires. Twenty healthy subjects were asked to compare the visual recognizability of several rat tissues between the illuminations in test colors and white. The rats were anesthetized, and the femoral vein and abdominal cavity were exposed. Seven tissues were selected for a visual recognition test. Illumination was generated using a multi-color LED light. The subjects observed the tissues under the illuminations of white and one of the test colors alternately and reported which illumination is suitable for visual recognition using a questionnaire. The analysis of the questionnaires showed that the blue test color was more effective than white illumination in the visual recognition of fine structures such as the branching of blood vessels and nerves, and red illumination disturbed the visual recognizability of the same tissues. On the other hand, the red but not the blue illumination improved the visual recognizability of the vein beneath the intact skin. As to the recognition of individual tissues in the abdominal cavity, the white illumination gave a better visual recognizability compared to every other test color. This study shows that the illumination color influences the visual recognition of biological specimens and the adequate color for the visual recognition of specific tissue parts is distinct among biological specimens. Using the lighting system to make fine adjustments to the illumination color may be useful in medical diagnosis and surgery.

Ascorbate Deficiency Does Not Limit Nonphotochemical Quenching in Chlamydomonas reinhardtii.

Ascorbate (Asc; vitamin C) plays essential roles in development, signaling, hormone biosynthesis, regulation of gene expression, stress resistance, and photoprotection. In vascular plants, violaxanthin de-epoxidase requires Asc as a reductant; thereby, Asc is required for the energy-dependent component of nonphotochemical quenching (NPQ). To assess the role of Asc in NPQ in green algae, which are known to contain low amounts of Asc, we searched for an insertional Chlamydomonas reinhardtii mutant affected in theVTC2 gene encoding GDP-l-Gal phosphorylase, which catalyzes the first committed step in the biosynthesis of Asc. The Crvtc2-1 knockout mutant was viable and, depending on the growth conditions, contained 10% to 20% Asc relative to its wild type. When C. reinhardtii was grown photomixotrophically at moderate light, the zeaxanthin-dependent component of NPQ emerged upon strong red illumination both in the Crvtc2-1 mutant and in its wild type. Deepoxidation was unaffected by Asc deficiency, demonstrating that the Chlorophycean violaxanthin de-epoxidase found in C. reinhardtii does not require Asc as a reductant. The rapidly induced, energy-dependent NPQ component characteristic of photoautotrophic C. reinhardtii cultures grown at high light was not limited by Asc deficiency either. On the other hand, a reactive oxygen species-induced photoinhibitory NPQ component was greatly enhanced upon Asc deficiency, both under photomixotrophic and photoautotrophic conditions. These results demonstrate that Asc has distinct roles in NPQ formation in C. reinhardtii as compared to vascular plants.

Dielectric multi-momentum meta-transformer in the visible

Metasurfaces as artificially nanostructured interfaces hold significant potential for multi-functionality, which may play a pivotal role in the next-generation compact nano-devices. The majority of multi-tasked metasurfaces encode or encrypt multi-information either into the carefully tailored metasurfaces or in pre-set complex incident beam arrays. Here, we propose and demonstrate a multi-momentum transformation metasurface (i.e., meta-transformer), by fully synergizing intrinsic properties of light, e.g., orbital angular momentum (OAM) and linear momentum (LM), with a fixed phase profile imparted by a metasurface. The OAM meta-transformer reconstructs different topologically charged beams into on-axis distinct patterns in the same plane. The LM meta-transformer converts red, green and blue illuminations to the on-axis images of “R”, “G” and “B” as well as vivid color holograms, respectively. Thanks to the infinite states of light-metasurface phase combinations, such ultra-compact meta-transformer has potential in information storage, nanophotonics, optical integration and optical encryption.