Blue-green Range Research Articles

Hydrothermal synthesis and optical luminescence center attribution in samarium-doped zirconia nanocrystals

Sm[Formula: see text] -doped ZrO2 (SDZ) nanocrystals were prepared via a hydrothermal route without subsequent calcination. These samples underwent a series of characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy, and photoluminescence (PL) spectral. The results showed pure cubic ZrO2 nanocrystals, with a crystallite size of 8.4 nm, were achieved by doping 8 mol% Sm[Formula: see text]. It was observed that the concentration of Sm[Formula: see text] had a significant impact on the crystallite structure of the samples, which exhibited an array of spherical shape and irregular aggregates. The inclusion of PL emission bands, spanning from the ultraviolet to blue-green range, highlighted three distinct bands. These were analyzed using Gaussian fittings and were attributed to three different types of defects, referred to as the F, F1, and F2 centers, respectively.

Multivalency-induced structural variations of 2D selenium nanosheets: facile solution-phase synthesis and optical properties.

The structural stability of two-dimensional (2D) phases derived from bulk selenium (Se) is intrinsically rooted in the multivalent nature of the material. The emergence of 2D Se, as its morphology evolves from 1D to 2D, was initially inspired by theoretical predictions of various quasi-stable structural phases of 2D Se. Here, we report a facile liquid-phase synthesis of free-standing few-layer selenium nanosheets (SeNS) employing a simple magnetic stirring of their bulk counterpart in N-methyl pyrrolidone (NMP). The synthesized SeNS possess lateral dimensions ranging from several hundreds of nanometers to a few microns, with a minimum thickness of ∼1 nm. High-resolution transmission electron microscopy reveals the existence of α- and β-selenene. Fourier transform infrared analysis suggests that the inherent surface/edge functionalization of 2D SeNS by NMP enhances their dispersion stability. The UV-vis-NIR absorption spectrum of SeNS exhibits a shoulder peak at 330 nm, attributed to surface/edge functionalization, and multiple peaks across the vis-NIR region, stemming from size quantization effects. The functionalized selenium nanosheets generate photoluminescence that spans the blue-green range, while the size quantization of SeNS leads to green-orange luminescence. The non-linear optical studies following Z-scan experiments with an open aperture revealed reverse saturable absorption (RSA) and strong optical limiting in 2D SeNS under 532 nm, 10 ns laser pulses. Notably, a transition from RSA to saturable absorption (SA) has also been observed in samples stirred over an extended period. In this perspective, the results illustrate the first experimental realization of free-standing multivalent 2D selenium in allotropic forms with unique optical properties.

Brightness and purity of a room-temperature single-photon source in the blue-green range.

We discuss a promising solid-state system that emits single photons at room temperature in the blue-green range, making it an attractive candidate for quantum communications in free space and underwater. The active element is a core-shell ZnSe tapered nanowire embedding a single CdSe quantum dot grown by molecular beam epitaxy. A patterned substrate enables a comprehensive study of a single nanowire using various methods. Our source shows potential for achieving a total brightness of 0.17 photon per pulse and anti-bunching with g(2)(0) < 0.3 within a restricted spectral window. Additionally, we analyze the impact of charged excitons on the g(2)(0) value in different spectral ranges.

Quantitative analysis of the blue-green single-photon emission from a quantum dot in a thick tapered nanowire

Quantum dots (QDs) acting as single-photon emitters in the blue-green range are fabricated and characterized at cryogenic temperature. They consist in CdSe dots inserted in (Zn,Mg)Se nanowires with a thick shell. Photoluminescence spectra, decay curves, and autocorrelation functions were measured under nonresonant continuous-wave and pulsed excitation. An analytical approach is applied simultaneously to the decay curves and correlation functions. It allows a quantitative description of how these two quantities are affected by the exciton rise due to biexciton feeding, the bright exciton decay, the effect of the dark exciton, and the reexcitation between two laser pulses. Linewidths at our limit of resolution (200 $\ensuremath{\mu}\mathrm{eV}$) are recorded. The reported correlation counts vary from a full control by reexcitation from traps, to a small contribution of reexcitation by mobile carriers or other QDs, as low as 5%.

Development of flexible scintillation sensors based on Ag and Gd doped CdWO4 nanocomposites

In this work, CdWO4 (CWO), CWO: Ag, and CWO: Gd nanoparticles (NPs) were synthesized by a simple method. Incorporation of the prepared NPs in a polymeric matrix (Polyester) developed a highly luminescent and ionizing ray nanocomposite sensor. Results from XRD, XPS, FE-SEM and EDAX, verified the successful synthesize of pure and doped CWO nanoparticles with the mean size of approximately 50–70 nm. The luminescence properties of the synthesized NPs were examined under UV and ion-beam excitation. CWO: Ag nanoparticles exhibited the most intense emission in the blue-green range compared to the CWO and CWO: Gd samples. The scintillation response of the prepared composite films against alpha irradiation (241Am source) was studied. The highest absolute efficiency (ε) was obtained for CWO: Ag composite film (58.18%) which has promising applications in flexible and transparent optical detectors.

Synthesize and optical response of ZnO/CdWO4: Ce nanocomposite with high sensitivity detection of ionizing radiations

Pure and cerium doped zinc oxide/cadmium tungstate (ZnO/CdWO4: Ce) nanocomposites were synthesized by an affordable route. Various approaches were applied to study the structural and optical features of prepared samples. For the first time, ionization radiation responses of ZnO/CdWO4: Ce nanocomposites were investigated using 241Am source and ionoluminescence measurements. Under a Xe source of radiation, photocurrent transient responses of produced nanocomposites were also detected. Doped nanocomposite showed strong emission in the blue-green range and excellent photosensitivity at room temperature compared to pure samples. The average diameter particle size of nanoparticles was in the range of 102–168 nm. Results from XRD, XPS, FTIR, and EDX verified the presence of ZnO, CdWO4, chemical bindings, and associated components in the composites. Obtained results showed that the optical response of the ZnO/CWO: Ce nanocomposite was improved when compared with bare ZnO, CdWO4, and pure ZnO/CdWO4; as a result, the synthesized nanocomposite is expected to have promising applications in optoelectronic devices.

Implications of open circuit voltage of light-emitting diodes installed for plant cultivation

This study investigated a light sensor function of light-emitting diodes (LEDs), the use of which is expanding in plant cultivations. Unimodal spectral LEDs of four types with respective emission peak wavelengths of 464, 501, 634, and 849 nm, and a white LED with a bimodal spectrum with 455-nm primary and 574-nm secondary peaks were used for this study. Open circuit voltage (VOC) of up to 1-2 V was induced in the LEDs when they were irradiated with sunlight. The VOC value of the 634 nm LED saturated with a low photon flux density can be used for binary discrimination between daylight and night. Each LED had a VOC inducible threshold wavelength of incident light. By virtue of the wavelength threshold feature, existence of a plant leaf between a light source and the LEDs is detectable by comparing the VOC values of blue-green range LEDs (464 nm, 501 nm) and near-infrared (NIR) LEDs (849 nm). Under leaf shadow, the NIR LED VOC exceeded those of the blue-green range LEDs. Under natural incident sunlight, the VOCs of the blue-green range LEDs were greater than that of the NIR LED. Another function of LEDs in agricultural use has been demonstrated.

Nitrogen and sulfur co-doped carbon dots with bright fluorescence for intracellular detection of iron ion and thiol

Carbon dots (CDs) have been widely used in recent years because of their excellent water solubility and abundant surface functional groups. However, compared with quantum dots or biological probes, the quantum yield of CDs is lower, and the fluorescence mainly concentrated in the blue-green range, which significantly limits the biological applications of CDs. Heteroatoms doping is the most common method to improve the luminescence of CDs. In this work, nitrogen and sulfur co-doped luminescent CDs were successfully synthesized by microwave assisted method using glutathione (GSH) and p-phenylenediamine (PPD) as raw materials. It can emit bright green fluorescence in ethanol solution, and the maximum emission wavelength is 535 nm when excited at 374 nm, and the absolute quantum yield is as high as 63%. Iron ion (Fe3+) can interact with the functional groups on the surface of the CDs to form CDs/Fe3+, which is a non-fluorescence complex, and Fe3+ can be reduced to ferrous ion (Fe2+). In other words, the reaction mechanism of CDs and Fe3+ is a combination of dynamic quenching and static quenching. The fluorescence of CDs quenched by Fe3+ can be restored by thiol, because there is a stronger binding force between sulfhydryl (-SH) on the surface of thiol and Fe3+, which enables CDs to be released. In addition, the CDs has good biocompatibility and stability, indicating that it has excellent potential in bioimaging. This discovery will expand the application of CDs in the fields of biosensing and imaging.

Bit error rate performance of underwater optical wireless communication test bed simulating the seawater conditions

Underwater wireless communication (UWC) is one of the most challenging forms of communication due to the dynamic nature of oceans. At present acoustic communication is the most mature technology available for UWC. However, this technology has limitations in terms of bandwidth, data rates, latency, multipath propagation, etc., Radio frequency communication is also not feasible in the underwater environment due to the high conductivity of the sea water and high absorption of RF waves in fresh water. Underwater Wireless Optical Communication (UWOC) has lots of potential in water environment and has an advantage over acoustic and RF in terms of higher data rates, bandwidth, least latency, low power requirement, and small components. The blue-green visible range of the visible spectrum (410–550 nm) has the least attenuation underwater, i.e. low absorption and scattering. Although UWOC promises the said advantages but also has a lot of challenges. In this paper, we aim at evaluation a link performance of UWOC test bed (in a laboratory scale) with varying salinity and turbidity close to the sea water conditions in a water tank. The results indicate the trends of deterioration of BER with the increasing salinity and turbidity and the need of power requirement of laser for clear oceans to get higher ranges and requirement of the better receiver to get satisfactory ranges in coastal water.

Facile synthesis of ZnO/CWO nanocomposite with brilliant enhanced optical response

In this research, novel zinc oxide/cadmium tungstate (ZnO/CWO) nanocomposite was prepared by a simple chemical method. The prepared nanocomposite was characterized for its structural and optical properties by different techniques. For the first time, the radiation response of prepared nanocomposite was studied using 241Am alpha source and ion beam induced luminescence (IBIL) measurement. Also, photocurrent transient responses of the prepared nanocomposite were recorded under Xe source radiation. ZnO/CWO nanocomposite exhibited strong light emission in the blue-green range at room temperature. Under alpha irradiation, the ZnO/CWO nanocomposite showed an excellent sensitivity when compared to pure ZnO or CWO. FESEM and TEM images showed a uniform distribution of spherical nanoparticles with an average particle size of 77 nm. XRD, XPS, and EDX results indicated characteristic peaks of ZnO, CWO, and related elements in the composite. Fourier transform infrared spectroscopy confirmed the presence of several groups in the nanocomposite. Investigations indicated that the optical quality of the ZnO/CWO nanocomposite was improved when compared with pure ZnO and CWO. According to obtained results, it is anticipated that ZnO/CWO nanocomposite would hold suitable potential for applications in optoelectronic devices and detection.

Sensory systems of Lineus ruber (Nemertea, Pilidiophora)

The aim of this study was to examine the organization of sensory systems in the heteronemertean Lineus ruber (Muller, 1774). Sensory systems of the head region (cerebral and frontal organs), body wall, proboscis and digestive tract of L. ruber were studied using Golgi–Colonnier silver impregnation, glyoxylic acid-induced fluorescence method for catecholamines (CAs) and immunochemical staining for serotonin (5-HT) and FMRFamide-related peptides (FaRPs). The study revealed a large number of intra- and subepithelial sensory cells in all of these structures and body regions. Only some of the sensory cells identified by silver impregnation were positive for CAs, 5-HT or FaRPs; the remaining cells appear to have different neurotransmitter modality. CA-containing (CA-C) intra- and subepithelial sensory cells were the most common cell types and were present in the epidermis and all the organs studied. All CA-C cells had a stiff cilium, which showed glyoxylic acid-induced fluorescence in the blue–green range indicative of CAs. In addition to CA-C cells, the cerebral organs had FaRP-immunoreactive sensory cells and argyrophilic cells containing an unidentified neurotransmitter and the frontal organs contained the neurites of 5-HT-immunoreactive, most likely efferent neurons. The presence of presumably mechanoreceptive CA-C cells in the frontal and cerebral organs indicates that these organs may perform not only a chemosensory, but also mechanosensory function.

Theoretical and Experimental Investigations of Large Stokes Shift Fluorophores Based on a Quinoline Scaffold.

A series of novel styrylquinolines with the benzylidene imine moiety were synthesized and spectroscopically characterized for their applicability in cellular staining. The spectroscopic study revealed absorption in the ultraviolet–visible region (360–380 nm) and emission that covered the blue-green range of the light (above 500 nm). The fluorescence quantum yields were also determined, which amounted to 0.079 in the best-case scenario. The structural features that are behind these values are also discussed. An analysis of the spectroscopic properties and the theoretical calculations indicated the charge-transfer character of an emission, which was additionally evaluated using the Lippert–Mataga equation. Changes in geometry in the ground and excited states, which had a significant influence on the emission process, are also discussed. Additionally, the capability of the newly synthesized compounds for cellular staining was also investigated. These small molecules could effectively penetrate through the cellular membrane. Analyses of the images that were obtained with several of the tested styrylquinolines indicated their accumulation in organelles such as the mitochondria and the endoplasmic reticulum.

Directed UV and X-ray generation in nanomaterials at the optical excitation

Efficient electromagnetic emission of radiation in the spectral range with wavelengths shorter than exciting light wavelength was observed at the nanomaterials excitation by laser pulses. Emission was registered in a visible (blue-green) range, in vacuum UV and in soft X-ray. Luminescence was registered both in the air and in the vacuum chamber. Synthetic opal matrices and nanocomposites on their base (matrices infiltrated with different liquids) were used as samples. Luminescence was excited with the help of different lasers: ruby laser, second harmonic of Nd:YAG laser and copper vapor laser. In the visible range two regimes of luminescence were observed: fast (few μs) and slow (up to 12 s). Slow luminescence was registered at temperatures lower than 110 K. Spectra of X-ray emission were registered. The connection of this emission with the triboluminescence effect is considered.

Categorical colour perception occurs in both signalling and non-signalling colour ranges in a songbird.

Although perception begins when a stimulus is transduced by a sensory neuron, numerous perceptual mechanisms can modify sensory information as it is processed by an animal's nervous system. One such mechanism is categorical perception, in which (1) continuously varying stimuli are labelled as belonging to a discrete number of categories and (2) there is enhanced discrimination between stimuli from different categories as compared with equally different stimuli from within the same category. We have shown previously that female zebra finches ( Taeniopygia guttata) categorically perceive colours along an orange-red continuum that aligns with the carotenoid-based coloration of male beaks, a trait that serves as an assessment signal in female mate choice. Here, we demonstrate that categorical perception occurs along a blue-green continuum as well, suggesting that categorical colour perception may be a general feature of zebra finch vision. Although we identified two categories in both the blue-green and the orange-red ranges, we also found that individuals could better differentiate colours from within the same category in the blue-green as compared with the orange-red range, indicative of less clear categorization in the blue-green range. We discuss reasons why categorical perception may vary across the visible spectrum, including the possibility that such differences are linked to the behavioural or ecological function of different colour ranges.

Intrinsic blue-green fluorescence in amyloyd fibrils

Proteins and polypeptides containing a high proportion of β-sheets have been recently reported to exhibit, in their amyloid aggregated states, an intrinsic fluorescence in the blue-green range of wavelength where the aromatic residues do not emit. Lately, growing attention has been devoted to the identification of a specific, structure-related fluorophore for the detection of amyloid aggregates due to their implications in the physio-pathology of neurodegenerative diseases and other aggregation-related diseases. Indeed, the appearance of blue-green fluorescence could be used as an alternative method for the investigation and the detection of the aggregation state without using external probes. Several hypotheses have been suggested to explain the molecular bases of this rather unusual intrinsic emission. In particular, it has been related to an expansion of the electronic delocalization of π-electrons of peptide bonds through the backbone-to-backbone hydrogen bonds connecting the β-sheets. Alternatively, the formation of the intrinsic chromophore has been associated to chemical modifications of the aromatic residues or arising from dipolar coupling between excited states of aromatic amino acids densely packed in the fibril structures. More recently, it has been proposed that the blue-green amyloid fluorophore does not require neither the presence of aromatic residues nor multiple bond conjugation. In this study, we critically review the above hypotheses with particular attention to the electronic transitions responsible for the appearance of blue-green fluorescence in amyloid fibrils.

A Low Ratio of Red/Far-Red in the Light Spectrum Accelerates Senescence in Nest Leaves of Platycerium Bifurcatum

AbstractThe fern Platycerium bifurcatum is a valuable component of the flora of tropical forests, where degradation of local ecosystems and changes in lighting conditions occur due to the increasing anthropogenic pressure. In ferns, phytochrome mechanism responsible for the response to changes in the value of R/FR differs from the mechanism observed in spermatophytes. This study analyzed the course of ontogenesis of nest leaves in P. bifurcatum at two values of the R/FR ratio, corresponding to shadow conditions (low R/FR) and intense insolation (high R/FR). The work used only non-destructive research analysis, such as measurements of reflectance of radiation from the leaves, their blue-green and red fluorescence, and the chlorophyll a fluorescence kinetics. This allowed tracing the development and aging processes in the same leaves. Nest leaves are characterized by short, intense growth and rapid senescence. The study identified four stages of development of the studied leaves related to morphological and anatomical structure and changing photochemical efficiency of PSII. Under the high R/FR ratio, the rate of ontogenesis of the leaf lamina was much slower than under the low R/FR value. As shown, the rapid aging of the leaves was correlated with faster decline of the chlorophyll content. It was shown that leaf senescence was accompanied by accumulation of polyphenols, anthocyanins and carotenoids on the basis of reflectance and fluorescence measurements in the blue-green range.

Turn-on Fluorene Push-Pull Probes with High Brightness and Photostability for Visualizing Lipid Order in Biomembranes.

The rational design of environmentally sensitive dyes with superior properties is critical for elucidating the fundamental biological processes and understanding the biophysical behavior of cell membranes. In this study, a novel group of fluorene-based push-pull probes was developed for imaging membrane lipids. The design of these fluorogenic conjugates is based on a propioloyl linker to preserve the required spectroscopic features of the core dye. This versatile linker allowed the introduction of a polar deoxyribosyl head, a lipophilic chain, and an amphiphilic/anchoring group to tune the cell membrane binding and internalization. It was found that the deoxyribosyl head favored cell internalization and staining of intracellular membranes, whereas an amphiphilic anchor group ensured specific plasma membrane staining. The optimized fluorene probes presented a set of improvements as compared to commonly used environmentally sensitive membrane probe Laurdan such as red-shifted absorption matching the 405 nm diode laser excitation, a blue-green emission range complementary to the red fluorescent proteins, enhanced brightness and photostability, as well as preserved sensitivity to lipid order, as shown in model membranes and living cells.

Measurement of non-equilibrium carriers dynamics in Ce-doped YAG, LuAG and GAGG crystals with and without Mg-codoping

Non-linear absorption spectroscopy in pump and probe configuration has been used to test the population of non-equilibrium carriers in Ce-doped Y3Al5O12 (YAG), Lu3Al5O12 (LuAG), and Gd3AlxGa(5-x)O12 (GAGG) crystals with and without codoping by Mg2+ ions. A faster rise time of the induced optical density has been observed in all crystals codoped with Mg with respect to that in Mg-free samples. A significant difference in the time evolution of the differential optical density in GAGG with respect to YAG and LuAG crystals has also been measured. In both GAGG:Ce and GAGG:Ce,Mg an absorption band with maximum in the blue-green range and a decay time of 1.4ps is present. This band is due to the absorption by free electrons before they are trapped or re-captured by Ce3+ ions. A broad absorption band in the yellow-red region with very short rise time and a decay time longer than 150ps has been observed in all the Ce-doped garnets under study and can be attributed to the absorption from the Ce3+ excited states.

SPECTRAL FEATURE ANALYSIS FOR QUANTITATIVE ESTIMATION OF CYANOBACTERIA CHLOROPHYLL-A

In recent years, lake eutrophication caused a large of Cyanobacteria bloom which not only brought serious ecological disaster but also restricted the sustainable development of regional economy in our country. &amp;lt;i&amp;gt;Chlorophyll-a&amp;lt;/i&amp;gt; is a very important environmental factor to monitor water quality, especially for lake eutrophication. Remote sensed technique has been widely utilized in estimating the concentration of &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt; by different kind of vegetation indices and monitoring its distribution in lakes, rivers or along coastline. For each vegetation index, its quantitative estimation accuracy for different satellite data might change since there might be a discrepancy of spectral resolution and channel center between different satellites. The purpose this paper is to analyze the spectral feature of &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt; with hyperspectral data (totally 651 bands) and use the result to choose the optimal band combination for different satellites. The analysis method developed here in this study could be useful to recognize and monitor cyanobacteria bloom automatically and accrately. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt; In our experiment, the reflectance (from 350nm to 1000nm) of wild cyanobacteria in different consistency (from 0 to 1362.11ug/L) and the corresponding &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt; concentration were measured simultaneously. Two kinds of hyperspectral vegetation indices were applied in this study: simple ratio (SR) and narrow band normalized difference vegetation index (NDVI), both of which consists of any two bands in the entire 651 narrow bands. Then multivariate statistical analysis was used to construct the linear, power and exponential models. After analyzing the correlation between &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt; and single band reflectance, SR, NDVI respetively, the optimal spectral index for quantitative estimation of cyanobacteria &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt;, as well corresponding central wavelength and band width were extracted. Results show that: Under the condition of water disturbance, SR and NDVI are both suitable for quantitative estimation of &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt;, and more effective than the traditional single band model; the best regression models for SR, NDVI with &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt; are linear and power, respectively. Under the condition without water disturbance, the single band model works the best. For the SR index, there are two optimal band combinations, which is comprised of infrared (700nm-900nm) and blue-green range (450nm-550nm), infrared and red range (600nm-650nm) respectively, with band width between 45nm to 125nm. For NDVI, the optimal band combination includes the range from 750nm to 900nm and 700nm to 750nm, with band width less than 30nm. For single band model, band center located between 733nm-935nm, and its width mustn’t exceed the interval where band center located in. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt; This study proved , as for SR or NDVI, the centers and widths are crucial factors for quantitative estimating &amp;lt;i&amp;gt;chlorophyll-a&amp;lt;/i&amp;gt;. As for remote sensor, proper spectrum channel could not only improve the accuracy of recognizing cyanobacteria bloom, but reduce the redundancy of hyperspectral data. Those results will provide better reference for designing the suitable spectrum channel of customized sensors for cyanobacteria bloom monitoring at a low altitude. In other words, this study is also the basic research for developing the real-time remote sensing monitoring system with high time and high spatial resolution.

SPECTRAL FEATURE ANALYSIS FOR QUANTITATIVE ESTIMATION OF CYANOBACTERIA CHLOROPHYLL-A

Abstract. In recent years, lake eutrophication caused a large of Cyanobacteria bloom which not only brought serious ecological disaster but also restricted the sustainable development of regional economy in our country. Chlorophyll-a is a very important environmental factor to monitor water quality, especially for lake eutrophication. Remote sensed technique has been widely utilized in estimating the concentration of chlorophyll-a by different kind of vegetation indices and monitoring its distribution in lakes, rivers or along coastline. For each vegetation index, its quantitative estimation accuracy for different satellite data might change since there might be a discrepancy of spectral resolution and channel center between different satellites. The purpose this paper is to analyze the spectral feature of chlorophyll-a with hyperspectral data (totally 651 bands) and use the result to choose the optimal band combination for different satellites. The analysis method developed here in this study could be useful to recognize and monitor cyanobacteria bloom automatically and accrately. In our experiment, the reflectance (from 350nm to 1000nm) of wild cyanobacteria in different consistency (from 0 to 1362.11ug/L) and the corresponding chlorophyll-a concentration were measured simultaneously. Two kinds of hyperspectral vegetation indices were applied in this study: simple ratio (SR) and narrow band normalized difference vegetation index (NDVI), both of which consists of any two bands in the entire 651 narrow bands. Then multivariate statistical analysis was used to construct the linear, power and exponential models. After analyzing the correlation between chlorophyll-a and single band reflectance, SR, NDVI respetively, the optimal spectral index for quantitative estimation of cyanobacteria chlorophyll-a, as well corresponding central wavelength and band width were extracted. Results show that: Under the condition of water disturbance, SR and NDVI are both suitable for quantitative estimation of chlorophyll-a, and more effective than the traditional single band model; the best regression models for SR, NDVI with chlorophyll-a are linear and power, respectively. Under the condition without water disturbance, the single band model works the best. For the SR index, there are two optimal band combinations, which is comprised of infrared (700nm-900nm) and blue-green range (450nm-550nm), infrared and red range (600nm-650nm) respectively, with band width between 45nm to 125nm. For NDVI, the optimal band combination includes the range from 750nm to 900nm and 700nm to 750nm, with band width less than 30nm. For single band model, band center located between 733nm-935nm, and its width mustn’t exceed the interval where band center located in. This study proved , as for SR or NDVI, the centers and widths are crucial factors for quantitative estimating chlorophyll-a. As for remote sensor, proper spectrum channel could not only improve the accuracy of recognizing cyanobacteria bloom, but reduce the redundancy of hyperspectral data. Those results will provide better reference for designing the suitable spectrum channel of customized sensors for cyanobacteria bloom monitoring at a low altitude. In other words, this study is also the basic research for developing the real-time remote sensing monitoring system with high time and high spatial resolution.