Blue Wavelength Region Research Articles

Light response of poly(ethylene 2,6-naphthalate) to neutrons

There is an increasing necessity for low background active materials as ton-scale, rare-event and cryogenic detectors are developed. Poly(ethylene-2,6-naphthalate) (PEN) has been considered for these applications because of its robust structural characteristics, and its scintillation light in the blue wavelength region. Radioluminescent properties of PEN have been measured to aid in the evaluation of this material. In this article we present a measurement of PEN’s quenching factor using three different neutron sources; neutrons emitted from spontaneous fission in 252Cf , neutrons generated from a DD generator, and neutrons emitted from the 13C(α,n)16O and the 7Li(p,n)7Be nuclear reactions. The fission source used time-of-flight to determine the neutron energy, and the neutron energy from the nuclear reactions was defined using thin targets and reaction kinematics. The Birks’ factor and scintillation efficiency were found to be kB = 0.12 ± 0.01 mm MeV−1 and S = 1.31 ± 0.09 MeVeeMeV−1 from a simultaneous analysis of the data obtained from the three different sources. With these parameters, it is possible to evaluate PEN as a viable material for large-scale, low background physics experiments.

Anti-Corrosion SiOx-Doped DLC Coating for Raster Steel Linear Scales

In this study, we investigated the efficacy of SiOx-doped diamond-like carbon (DLC) films for enhancing the corrosion resistance of raster steel linear scales. The research work highlights the significant role of DLC film materials in enhancing corrosion resistance, making them a promising solution for various industrial applications. The Raman spectroscopy analysis of SiOx-doped DLC films, synthesized via a direct ion beam technique with HMDSO vapor, revealed prominent D and G bands characteristic of amorphous carbon materials, with a high degree of disorder indicated by an ID/IG ratio of 1.85. X-ray diffraction patterns confirmed the amorphous nature of the SiOx-doped DLC films and the minimal impact of the DLC deposition process on the underlying crystalline structure of steel. UV–Vis-NIR reflectance spectra of SiOx-doped DLC on stainless steel demonstrated improvements in the blue wavelength region compared to stainless steel with ripples alone, which is beneficial for applications utilizing blue light. Corrosion tests, including immersion in a 5% salt solution and salt spray testing, showed that SiOx-doped DLC-coated stainless steel exhibited superior corrosion resistance compared to uncoated steel, with no significant signs of corrosion observed after extended exposure. These findings underscore the potential of SiOx-doped DLC coatings to provide long-term corrosion protection and maintain the structural integrity and surface quality of steel components in harsh environments.

Morphology and spectral sensitivity of long visual fibers and lamina monopolar cells in the butterfly Papilio xuthus.

Extensive analysis of the flower-visiting behavior of a butterfly,Papilio xuthus, has indicated complex interaction between chromatic, achromatic, and motion cues. Their eyes are spectrally rich with six classes of photoreceptors, respectively sensitive in the ultraviolet, violet, blue, green, red, and broad-band wavelength regions. Here, we studied the anatomy and physiology of photoreceptors and second-order neurons ofP. xuthus, focusing on their spectral sensitivities and projection terminals to address where the early visual integration takes place. We thus found the ultraviolet, violet, and blue photoreceptors and all second-order neurons terminate in the distal region of the second optic ganglion, the medulla. We identified five types of second-order neurons based on the arborization in the first optic ganglion, the lamina, and the shape of the medulla terminals. Their spectral sensitivity is independent of the morphological types but reflects the combination of pre-synaptic photoreceptors. The results indicate that the distal medulla is the most plausible region for early visual integration.

A-Site Cation Replacement of Hydrazinium Lead Iodide Perovskites by Borane Ammonium Ions: A DFT Calculation.

Organometallic perovskites have become one of the most common multifunctional materials in optoelectronic research fields. This research studies density functional theory calculation on orthorhombic hydrazinium lead iodide (N2 H5 PbI3 ) perovskite by replacing A-site cation with a borane ammonium (BH2 NH3 + ) ion. The perovskite showed a significant structural deformation and an orthorhombic to triclinic phase transition due to A-site ion replacement. The N2 H5 PbI3 perovskite has a band gap of 1.64 eV, suitable for the solar cell absorber layer. The band gap has increased to 2.12 eV after complete A-site ion replacement. All structures showed a high absorption coefficient over 104 cm-1 in the low wavelength region and an increase in refractive index from 2.5 to 2.75 due to ion replacement. All the structures showed high optical conductivity of 1015 s-1 order in the blue wavelength region. These new perovskite structures hold the potential to provide a revolution in optoelectronic research.

Tensor completion algorithm-aided structural color design.

In recent years, structural color has developed rapidly due to its distinct advantages, such as low loss, high spatial resolution and environmental friendliness. Various inverse design methods have been extensively investigated to efficiently design optical structures. However, the optimization method for the inverse design of structural color remains a formidable challenge. Traditional optimization approaches, such as genetic algorithms require time-consuming repetitions of structural simulations. Deep learning-assisted design necessitates prior simulations and large amounts of data, making it less efficient for systems with a small number of features. This study proposes a tensor completion algorithm capable of swiftly and accurately predicting missing datasets based on partially obtained datasets to assist in structural color design. Transforming the complex physical problem of structural color design into a spatial structure relationship problem linking geometric parameters and spectral data. The method utilizes tensor multilinear data analysis to effectively capture the complex relationships associated with geometric parameters and spectral data in higher-order data. Numerical and experimental results demonstrate that the algorithm exhibits high reliability in terms of speed and accuracy for diverse structures, datasets of varying sizes, and different materials, significantly enhancing design efficiency. The proposed algorithm offers a viable solution for inverse design problems involving complex physical systems, thereby introducing a novel approach to the design of photonic devices. Additionally, numerical experiments illustrate that the structural color of cruciform resonators with diamond can overcome the high loss issues observed in traditional dielectric materials within the blue wavelength region and enhance the corrosion resistance of the structure. We achieve a wide color gamut and a high-narrow reflection spectrum nearing 1 by this structure, and the theoretical analysis further verifies that diamond holds great promise in the realm of optics.

Highly efficient and water-resistant K3ZrF7:Mn4+ red-emitting phosphors

Mn4+ activated fluorides are promising red phosphors to be used in warm white light emitting diodes and liquid crystal display (LCD) backlighting due to their unique narrow-band red emission and broad band absorption in blue wavelength region. However, the instability in humid environment of these phosphors limited their practical application. In this work, we developed a facile co-precipitate method to prepare Mn4+ doped K3ZrF7 phosphors with good water-resistant properties. The crystal structure of K3ZrF7 was analyzed by XRD Rietveld refinement. The photoluminescence intensity was maintained at 95% after being immersed in water for 40 min in comparison with only 39.8% for Mn4+ doped K2TiF6 phosphors. The intrinsic seven coordination environment of Mn4+ in K3ZrF7 crystal was proposed as the main reason contributing to the good water resistance of the sample. The internal quantum efficiency and external quantum efficiency of optimized K3ZrF7:Mn4+ was measured to be 70.8% and 19.5% respectively. The thermal stability of the obtained phosphors was studied. A warm white light LED device with color temperature of 4074 K and color rendering index of 76.5 was fabricated by combining a mixture of K3ZrF7:Mn4+ and Y3Al5O12:Ce3+ with a blue InGaN chip.

Synthesis and Properties of Magnetic-Luminescent Fe3O4@ZnO/C Nanocomposites

A Fe3O4@ZnO/C nanocomposite with a core-shell structure was synthesized using the co-precipitation method. To prevent the aggregation of the Fe3O4 magnetic particles, polyethylene glycol (PEG) was added. The X-ray diffractometer (XRD) results confirmed the formation of Fe3O4 and ZnO phases, with Fe3O4 having a cubic crystal system and ZnO having a hexagonal crystal system. Carbon in Fe3O4@ZnO/C had no effect on the crystal structure of Fe3O4@ZnO. Images from transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed that the nanocomposite formed a core-shell structure. The Fourier transform infrared (FTIR) spectra verified the presence of bonds among ZnO, Fe3O4, and carbon. The appearance of the stretching vibration of the C≡C bond on the Fe3O4@ZnO/C sample revealed the nanocomposites’ carbon coupling. Photoluminescence (PL) spectroscopy was used to characterize the optical properties of the nanocomposites. Based on the results of the PL, the sample absorption of visible light was in the wavelength range of 400–700 nm. The photoluminescence of Fe3O4@ZnO differed from that of the Fe3O4@ZnO/C, especially in the deep-level emission (DLE) band. There was a phenomenon of broadening and shift of the band at a shorter wavelength, namely, in the blue wavelength region. Magnetic properties were characterized by vibrating-sample magnetometry (VSM). Based on the VSM results, the sample coupled with carbon exhibited a decrease in magnetic saturation. The presence of carbon changed photon energy into thermal energy. So, this material, apart from being a bioimaging material, can also be developed as a photothermal therapy material.

Photoinduced NO-release from polymer dots doped with an Ir(III) complex and N-methyl-N-nitroso-4-aminophenol.

Nitric oxide (NO) is a signaling molecule that plays a variety of functions in the human body, but it is difficult to use it in biological experiments or for therapeutic purposes because of its high reactivity and instability in the biological milieu. Consequently, photocontrollable NO releasers, which enable spatiotemporal control of NO release, have an important role in elucidating the functions of NO. Our group has developed visible-light-controllable NO-releasing molecules that contain a fluorescent dye structure as a light-harvesting antenna moiety and an N-nitrosoaminophenol structure as an NO-releasing moiety. Here, we aimed to construct an NO-generating system employing an intermolecular photoredox reaction between the two separate components, since this would simplify chemical synthesis and make it easier to examine various dyes as antennae. For this purpose, we constructed polymer nanoparticles doped with both N-methyl-N-nitroso-4-aminophenol (NAP, 1) and an Ir(III) antenna complex (2, 3 or 4) in order to dissolve in aqueous solution without a co-solvent. These polymer nanoparticles released NO upon photoirradiation in vitro in the purple (400-430 nm) or blue (400-460 nm) wavelength region to activate the doped Ir(III) complex.

NUV and VUV sensitive Silicon Photomultipliers technologies optimized for operation at cryogenic temperatures

The silicon photomultipliers (SiPMs) emerged as a promising solution in many applications, like high-energy physics experiments and recently, they are the detector of choice for the readout of liquid noble gases scintillators (e.g. liquid Xenon and liquid Argon) in large-area physics experiments. Here the SiPMs are operated at cryogenic temperatures. Important studies have been done to optimize SiPM performance for such conditions and we developed the NUV-HD-cryo and the VUV-HD-cryo technologies, with sensitivity optimized for the blue-wavelength and NUV range, or for the VUV range respectively. Important technological improvements have been demonstrated: (i) reduction of electric field, to lower band-to-band tunneling, (ii) doping profiles modifications to reduce afterpulsing at low temperatures and (iii) reduction of quenching resistor variation over temperature.In this work we show and compare the recent characterization results of primary noise, correlated noise and the dependences of the photon detection efficiency (PDE) and photon-number resolution of these SiPMs over temperature, between 300 K and 75 K.Primary dark count rate reduces to few counts per second already at 200 K, and of 7 orders of magnitude going towards liquid nitrogen temperature and the afterpulsing increment is mitigated. The PDE in the blue-wavelength region remain high in the investigated temperature range (>45%), while it changes at longer wavelengths and a good photon number resolution is preserved.

Performance enhancement of CIGS solar cells using ITO as buffer layer

The purpose of this research is the reduction of parasitic absorption to improve the CIGS solar cell performance. Decreasing the traditional CdS buffer layer thickness is a reduction method for parasitic absorption which yields to a higher photocurrent. However, degradation of the open-circuit voltage (Voc) and fill factor (FF) are observed in J-V measurements as a thin (<30 nm) CdS buffer layer is applied. Moreover, the toxic CdS has a relatively low bandgap which tends to a significant parasitic absorption in the blue wavelength region. Here, Indium Tin Oxide (ITO) with a larger bandgap is suggested as an alternative buffer layer, which unlike the CdS, demonstrates a significant efficiency enhancement without adversely affecting Voc and FF. ITO is an environmentally friendly substance which its ultra-thin thickness leads to a significant short-circuit current (Jsc) enhancement. Hence, an improvement of efficiency about 6% is achieved by successfully replacing the traditional CdS layer with ITO layer in conventional CIGS solar cell. Furthermore, ZnMgO (ZMO) with more transparency and larger bandgap, was applied to replace conventional ZnO window layer of the CIGS solar cell for further increment in Jsc. In addition, ZMO as a proper window layer in the proposed cell structure tends to the modification of J–V curve distortion at low temperatures. Ultimately, the final proposed structure with the alternative window layer (Mo/CIGS/ITO/ZMO/AZO) exhibited 7.5% efficiency improvement in comparison with the conventional solar cells.

A simple and sensitive electrochemiluminescence spectrum measurement platform and spectrum-resolved ratiometric sensor for miroRNA-141 determination

The electrochemiluminescence (ECL) spectral information is useful in ECL mechanism investigations, ratiometric ECL sensors and multi-analyte determinations. To overcome the shortcomings of low sensitivity in charge coupled devices (CCD) ECL spectrometer and low time efficiency for spectrum discrimination by using single band-pass filter (BPF) in one potential scan, a simple and sensitive ECL spectrum measurement platform is developed by placing a portable BPF array turntable device (with eleven measurement channels and one indicator channel) between the working electrode and photomultiplier in a conventional ECL analyzer. The systematic error due to the time dependent ECL intensity, which is the main obstacle for ECL spectrum measurement in wavelength scan mode, is neutralized by using the accumulated intensity for each channel in a group of spectrum measurement cycles. In a spectrum-resolved ratiometric ECL sensor for miroRNA-141 determination, near-infrared ECL emitter of methionine-stabilized Au nanoclusters (Met-Au NCs) is used as the tag and blue ECL emitter of g-C3N4 as the reference. The ratio of the total ECL intensity in near-infrared wavelength region (from Met-Au NCs) to that in blue wavelength region (from g-C3N4) is in linear correlation with the logarithmic concentration of microRNA-141 from 1 fM to 10 pM, with the limit of detection of 0.22 fM.

Heavy elements

How are the heavy elements formed? This has been a key open question in physics for decades. Recent direct detections of neutron star mergers and observations of evolved stars show signatures of chemical elements in the blue range of their spectra that bear witness of recent nuclear processes that led to heavy element production. The formation of heavy elements typically takes place through neutron-capture reactions creating radioactive isotopes, which following beta-decay turn into the stable isotopes we today can measure indirectly in the surfaces of cool, low-mass stars or meteoritic grains. The conditions (such as the neutron density or entropy) of these n-capture reactions remain to date poorly constrained, and only through a multidisciplinary effort can we, by combining and comparing observations, experiments, and theoretical predictions, improve on one of the top 10 most important open physics questions posed at the turn of the century. This emphasises the need for detailed observations of the near-UV to blue wavelength region. The shortage of spectrographs and hence spectra covering this range with high-resolution and high signal-to-noise has for decades played a limiting factor in our understanding of how heavy elements form in the nuclear reactions as well as how they behave in the stellar surfaces. With CUBES (Cassegrain U-Band Efficient Spectrograph) we can finally improve the observations, by covering the crucial blue range in more remote stars and also achieve a higher signal-to-noise ratio (SNR). This is much needed to detect and accurately deblend the absorption lines and in turn derive more accurate and precise abundances of the heavy elements.

Biomass‐derived porous carbon and colour‐tunable graphene quantum dots for high‐performance supercapacitor and selective probe for metal ion detection

The abundance of biomass waste and their alteration into carbon-based electrodes grants practical application of the same. The present work describes all-round utilization of orange peel waste for the synthesis of graphene quantum dots (GQDs) and carbon-based electrode fabricated via facile hydrothermal reaction. The supernatant liquid is used for Fe3+ ion sensing and the remnant material is used for synthesis of porous carbon for supercapacitor application. GQDs synthesised via hydrothermal and microwave technique showed dual emission in blue and green wavelength region. Presence of Fe3+ ions quenched the fluorescence of GQDs and the selectivity is studied using other metal ions. Concentration of Fe3+ is varied upto 2.0 mM and the corresponding photoluminescence intensity is observed in the range 85–195 unit, indicating the inverse proportionality relation between these parameters. Carbon obtained has a combination of meso/macro and microporous structure with surface area of 64.002 m2 g−1. Porous OC electrode is employed in three electrode system and is fabricated as coin-cell which delivered specific capacitance of 290.64 F g−1 and 146.9 F g−1, respectively. The asymmetrical supercapacitor delivered an efficiency of 86% after 10 000 charge-discharge cycle. The resultant material derived from this work is suitable for both energy and sensing application.

Designing high efficiency asymmetric polarization converter for blue light: a deep reinforcement learning approach.

Conventional polarization converters selectively preserve the required polarization state by absorbing, reflecting or refracting light with unwanted polarization state, leading to a theoretical transmittance limit of 0.5 for linearly polarized light with unpolarized light incidence. In the meanwhile, due to the high-dimensional structure parameters and time-consuming numerical simulations, designing a converter with satisfactory performance is extremely difficult and closely relies on human experts' experiences and manual intervention. To address these open issues, in this paper, we first propose an asymmetric polarization converter which shows both high transmittance for one linearly polarized light and high transmittance for the orthogonal linearly polarized light with 90° rotation in blue wavelength region. To maximize the performance of the proposed structure, a deep reinforcement learning approach is further proposed to search for the optimal set of structure parameters. To avoid overly long training time by using the numerical simulations as environment, a deep neural network is proposed to serve as the surrogate model, where a prediction accuracy of 96.6% and 95.5% in two orthogonal polarization directions is achieved with micro-second grade simulation time respectively. With the optimized structure, the average transmittance is larger than 0.5 for the wavelength range from 444 to 466 nm with a maximum of 0.605 at 455 nm, which is 21% higher than the theoretical limit of 0.5 of conventional polarization converters.

Layer-Dependent Raman Spectroscopy and Electronic Applications of Wide-Bandgap 2D Semiconductor β-ZrNCl.

In recent years, 2D layered semiconductors have received much attention for their potential in next-generation electronics and optoelectronics. Wide-bandgap 2D semiconductors are especially important in the blue and ultraviolet wavelength region, although there are very few 2D materials in this region. Here, monolayer β-type zirconium nitride chloride (β-ZrNCl) is isolated for the first time, which is an air-stable layered material with a bandgap of ≈3.0eV in bulk. Systematical investigation of layer-dependent Raman scattering of ZrNCl from monolayer, bilayer, to bulk reveals a blueshift of its out-of-plane A1g peak at ≈189cm-1 . Importantly, this A1g peak is absent in the monolayer, suggesting that it is a fingerprint to quickly identify the monolayer and for the thickness determination of 2D ZrNCl. The back gate field-effect transistor based on few-layer ZrNCl shows a high on/off ratio of 108 . These results suggest the potential of 2D β-ZrNCl for electronic applications.

The application of wide spectrum low peak blue light technology in health TV display

AbstractThe ever‐increasing utilization of blue light‐emitting diode in the field of the display has brought great damage to human eyes. Here, we demonstrate a method that reduces the damage caused by high concentrations of short‐wavelength blue light. Our wide spectrum and low peak backlight technology are based on replacing the existing common blue chip with a combination of shortwave blue‐chip and long‐wave blue chip. At the same time, a large number of blue‐filtering dye particles are coated on the optical film to reduce high‐energy blue light and achieve the effect of protecting the eyes. Therefore, our project can achieve up to 25 nm FWHM and a 50% reduction in peak blue light that is close to the continuous spectrum of natural light in the blue wavelength region. Numerical and experimental results, in a good agreement, demonstrate good performance of the proposed approach in liquid crystal display, with potential applications to eye‐friendly display.

Enhanced performance of GaN-based visible flip-chip mini-LEDs with highly reflective full-angle distributed Bragg reflectors

High-efficiency GaN-based visible flip-chip miniaturized-light emitting diodes (FC mini-LEDs) are desirable for developing white LED-backlit liquid crystal displays. Here, we propose a full-angle Ti3O5/SiO2 distributed Bragg reflector (DBR) for blue and green FC mini-LEDs to enhance the device performance. The proposed full-angle Ti3O5/SiO2 DBR is composed of different single-DBR stacks optimized for central wavelength in blue, green, and red light wavelength regions, resulting in wider reflective bandwidth and less angular dependence. Furthermore, we demonstrate two types of GaN-based FC mini-LEDs with indium-tin oxide (ITO)/DBR and Ag/TiW p-type ohmic contacts. Experimental results exhibit that the reflectivity of full-angle DBR is higher than that of Ag/TiW in the light wavelength range of 420 to 580 nm as the incident angle of light increases from 0° to 60°. As a result, the light output powers (LOPs) of blue and green FC mini-LEDs with ITO/DBR are enhanced by 7.7% and 7.3% in comparison to blue and green FC mini-LEDs with Ag/TiW under an injection current of 10 mA. In addition, compared with FC mini-LED with Ag/TiW, light intensity of FC mini-LED with ITO/DBR is improved in side direction, which is beneficial to mix light in backlight system of liquid crystal displays (LCDs).

Highly Efficient Blue Thermally Activated Delayed Fluorescence Top-Emitting OLEDs Achieved Via Combination of Multilayered Emissive Layer and Ag/WO3/Ag Transparent Cathode

Thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted immense research interest because of the merits including 100% internal quantum efficiency and absence of heavy metals as dopants. However, great challenges, accomplishing the viewing angle characteristic, color shift, high efficiency, and color purity, simultaneously, remain [1, 2]. Herein, we propose a concept of combining the multiple quantum well-based emissive layer (MQW-EML) and multilayered transparent cathode to overcome these challenges. The Ag/WO3/Ag (AWA) multilayers (12 nm/65 nm/12 nm) was optimized based on optical simulation for use as a transparent cathode that exhibits high transmittance (~85% in the visible and blue wavelength region) and low sheet resistance of 5.3 Ω/sq on glass substrates. Compared to thin Ag-based TADF top-emitting OLEDs (TEOLEDS), the proposed AWA-based TEOLED having MQW-EMLs displayed a 40% improvement in external quantum efficiency (Figure. 1). Importantly, the device exhibited a lower angular dependence as well as a low full width at half maximum (FWHM) value (~60 nm), indicating high color purity. These improvements are attributed to the synergistic effect of the MQW-EML and AWA transparent cathode. The EML with quantum well structure effectively confines the charges and excitons, thereby significantly improving color purity and efficiency. On the other hand, the optimized AWA transparent cathode improved the charge injection and light coupling as well. Therefore, this work is expected to open an avenue for high efficient TADF-TEOLEDs, via the combination of the multilayered EML and transparent cathode. Figure 1

Optical Bend Sensor Based on Eccentrically Micro-Structured Multimode Polymer Optical Fibers

We report on a novel bend sensor with high flexibility and elasticity based on Bragg grating structures in polymer optical fibers to detect bending for the measurement of movement. The concept is very simple and relies on the inscription of eccentrical Bragg gratings into multimode graded-index polymer optical fibers via contact exposure with a krypton fluoride excimer laser in the ultraviolet region and an optimized phase mask. Depending on the fiber deformation, the lattice constant of the inscribed Bragg grating is strained or compressed due to its position relative to the fiber core. This in turn results in a specific shift of the Bragg wavelength of up to $1.3\text{ nm}$ to the red or blue wavelength region, respectively, which is sufficiently large to be reliably detected. Therefore, as proof of principle, deformation along one axis can be observed with a single Bragg grating with a maximum sensitivity of up to $65\text{ pm/m}^{-1}$ . Moreover, multiple Bragg gratings inscribed into the same polymer optical fiber at different positions around the fiber axis allow to determine the shape deformation of the fiber relative to a reference frame with similar accuracy. Consequently, this technology could form the basis for new applications in the areas of medical diagnostics, robotics or augmented reality, which are lacking affordable sensor systems to date.

CAM18sl brightness prediction for unrelated saturated stimuli including age effects.

Modelling the influence of age on the perception of brightness of visual stimuli is an important topic for indoor and outdoor lighting. As people get older, the transmittance of the ocular media becomes lower, especially in the blue wavelength region. This paper reports on an experimental study aiming to evaluate how the brightness perception of red and blue stimuli is affected by the age of the observer. A matching experiment has been set up in which both young (25 years old on average) and older (70 years old on average) adult observers had to match the brightness of a blue stimulus with the brightness of a red stimulus, both surrounded by a dark background (unrelated stimuli). A significant difference in brightness perception between the two groups of observers was found. In particular, older people report a decrease in brightness perception for the blue stimuli compared to younger people. The results show that the brightness correlate of the colour appearance model CAM18sl (applied with zero luminance background) adequately predicts the matching results of young observers, but failed to predict the results obtained by the older observers. As CAM18sl is built on cone fundamentals which include the transmittance of the ocular media and consider the age of the observer as an input parameter, the authors developed the idea to substitute the cone fundamentals for a young observer by the cone fundamentals for a 70 years old observer. This updated CAM18sl performed very well for the older observer as well, on condition that the transmittance of the ocular media is isolated and kept out of the normalization of the cone fundamentals.