Type Of Light Source Research Articles

Combined Effects of the Electron–Hole Exchange and Förster Energy Transfer Interactions in Self‐Assembled Quantum‐Dot Pairs

Single‐photon emitters are essential components for the development of optical quantum computing and other quantum technologies, and semiconductor quantum dots are one of the most promising systems for scalable implementation of this type of light sources. However, polarization decoherence is still an important challenge to overcome. Herein, the combined influence of the electron–hole exchange and the Förster energy transfer in a pair of laterally coupled self‐assembled quantum dots, on the exciton‐spin coherence time, is studied. The numerical simulations suggest that under some conditions, the interplay between those two interactions slows the exciton‐spin decoherence as compared to the single‐dot case, which favors the applicability of quantum dots in quantum light generation devices.

Research note: On relation between photopic luminous efficacy and colour rendering of LED strips

Light-emitting diode (LED) strips have recently become a top-rated light source, used primarily in interior lighting applications. This increase is mainly due to increased performance in technical parameters, primarily photopic luminous efficacy (PLE) and the CIE general colour rendering index ( Ra). The relation between PLE and Ra was investigated for several types of light sources in the past and was found to be inversely related. However, confirming if a similar relation exists for the newest phosphor-converted LED strips based on up-to-date colour rendering metrics, such as TM-30-18 Rf (ANSI/IES), is essential. This study was based on measurements of 105 different phosphor-converted LED strips with correlated colour temperatures (CCTs) from 2500 K to 5000 K. The results showed that lower PLE and higher Ra usually characterize the group with lower CCTs than those with higher CCTs. In the group of LED strips below 3500 K, there is a strong negative linear correlation ( R2 = 0.51, p < 0.001) between PLE and Ra. However, in the group with CCTs above 3500 K, the linear correlation between PLE and Ra is weaker ( R2 = 0.29, p < 0.001). Moreover, the analysis of the relationship between PLE and TM-30-18 Rf showed no association between those variables. Results suggest the need to rethink the influence of PLE on colour rendering in the case of using modern metrics for LED lighting. Finally, the results are a reasonable basis for the further analysis of such associations, which should be done periodically according to the rapid development of LED light sources.

Influence of Different Light-Activated Bleaching Gels on Pulp Chamber Temperature: An In Vitro Study

Background: Significant advances in in-office bleaching treatments have been made by introducing some types of light sources. Halogen lights, LEDs, and diode lasers are the most popular devices used for in-office bleaching. There is a risk that bleaching-activating light sources might increase temperature and have side effects on the dental pulp. This study evaluated the effect of different light-activated bleaching gels on pulp chamber temperature. Methods: In this experimental study, 36 bovine incisor teeth were selected for investigation. The samples were divided into three groups, including Opalescence Xtra Boost PF bleaching gel with the 405 nm LED (group one), Opalescence Xtra Boost PF bleaching gel with 810 nm diode laser (group two), and Heydent bleaching gel with 810 nm diode laser (group three). Bleaching gels with a thickness of 1 mm were applied on teeth surfaces and activated according to the manufacturer’s instructions. The temperature change was recorded every second, and the results of the graph showing the peak temperature were plotted using SPSS software. One-way ANOVA was employed to determine the effect of bleaching type on temperature rise. In case of the presence of a significant difference, post-hoc Tukey’s test was utilized for pairwise comparison of the groups. Results: The temperature rise considerably depends on the light sources. Group one (LED+bleaching gel Xtra boost) had the lowest temperature rise (1.87° C±0.15), while group two (diode laser+bleaching gel Xtra boost) had the highest temperature rise (3.55° C±0.50). There was a statistically noticeable difference in temperature rise among all groups (P<0.05). Conclusion: The light activation of in-office bleaching gels with the diode laser caused higher temperature changes as compared to LED. However, the detected temperature rise was not critical for pulpal health.

Writing and optical characteristics of anti‐glare screens for educational applications

AbstractAs electronic displays have become to be used under ambient illumination environment, the situations have been increased which the screens are exposed to the various types of ambient light sources. Since the reflection of ambient light by the screen generally results in the lack of visibility of the displayed contents, anti‐glare layer (AGL) on top of the screen has been applied to suppress unwanted reflection. Meanwhile, handheld digital devices have been actively adopted to enhance the quality of learning experiences. Although it was pointed out that the impact of glare may lead to shorter viewing distance or poor posture of the students, there was not enough information regarding the relation between writing and optical characteristics of the anti‐glare screen. The purpose of this study is to provide information, which will help to select the appropriate screens for each application. Through the experiments with different AGLs and the displays, coefficient of friction, gloss value, sparkle contrast, and display modulation transfer function (MTF) were selected to characterize the writing and the optical characteristics. While the trend of the gloss values was similar to that of the display MTF, the trend of the sparkle contrast was different from them. These results were summarized as radar charts.

A comparative study of Cu-based nanoparticles and their spin-coated films: photocatalytic degradation mechanisms and efficiencies towards malachite green and neutral red azo dyes.

In this work, a comparison of the photocatalytic activity of free-standing Cu-based nanoparticle mixtures and spin-coated nanoparticle films under visible-light radiation is conducted. Herein, Cu2O, Cu2O-Cu, Cu2O-Cu3N-Cu, and Cu3N-Cu nanoparticle mixtures were successfully synthesized by a non-aqueous sol-gel route and then deposited on a glass substrate by spin-coating. The surface chemistry of the nanoparticles studied by X-ray photoelectron spectroscopy (XPS) allowed elucidating the nanoparticle synthesis mechanism. The UV-Vis absorption spectroscopy illustrates that photocatalytic activity is attributed to the high specific surface of the nanoparticles and their wider absorption range region from 500 to 1100nm. Unlike the free-standing photocatalysts, the photocatalytic effect of spin-coated nanoparticle films enabled their facile reclamation, which solves a key issue for practical applications of the photocatalysts. The photocatalytic performances on neutral red and malachite green organic dyes were influenced by the type of visible light sources, i.e., solar simulator and natural sunlight. The results indicate that photodegradation efficiency is the highest for Cu2O nanoparticles, reaching values of 82% for neutral red and 94% for malachite green. We also demonstrate that the degradation of cationic neutral red undergoes a photoconversion to its neutral form during the degradation process, which in turn, lowers its degradation efficiency. On the other hand, higher degradation efficiency was observed on malachite green owing to its unique cationic form, soluble in aqueous solutions.

Natural light vs artificial light. Effects of light pollution on the bioluminescence of dinoflagellate Pyrocystis lunula

Although there are thousands of marine bioluminescent species, very little is known about the effects of artificial light at night (ALAN) on these organisms, particularly those living near the sea surface, such as dinoflagellates. These organisms have a circadian clock that influences their rhythmic physiology, including processes like photosynthesis and nitrogen metabolism, which help regulate marine carbon and nitrogen cycles, respectively. The purpose of this study is to partially address this knowledge gap and research the effects of light pollution on the bioluminescent dinoflagellate Pyrocystis lunula through a series of experiments aimed at verifying the consequences due to changes in the normal day-night circadian cycle and exposure to different types of light source, colors, and light intensities. The response variable was the Corrected Total Algal Bioluminescence, which was recorded with a digital camera and then calculated with the ImageJ software. Results show that dinoflagellates do not appear to be susceptible to slight changes in the light/dark cycle. However, a total absence of light and darkness leads to a drastic inhibition of their bioluminescence, particularly under white LED or incandescent artificial light and with a light intensity of 100 lux or higher.

Inflammation and oxidative stress processes in induced precocious puberty in rats.

This study aimed to assess the influence of different types of blue light sources on male and female rats' puberty onset, the morphologic-induced alterations in reproductive organs tissues, the impact on inflammation and oxidative stress markers, anxiety levels, and mathematical modeling for tissue data interpretation. Four groups of sixteen rats each (8 females and 8 males/group) were investigated: three groups were exposed to blue light from mobile phones (MP), computer screens (PC), or LED lamps (LED) versus the control group (CTRL). The rats in the CTRL group had no exposure while the other groups were exposed for 30 days to the blue light of MP, PC, and LED for 16h per day. Serum levels of cortisol, TNF-α, IL-6, and MMP-2 and MMP-9 ovaries and testis tissue levels were analyzed using the ELISA technique. Total oxidative stress (TOS), nitric oxide (NO), and malondialdehyde (MDA) in serum were determined spectrophotometrically. Histomorphological examination was performed on both male and female genital organs. Rats of both sexes presented significant early onset of puberty secondary to blue light exposure. LED-emitted light significantly increased TNF-α and MMP-9 levels in both sexes. The MP and PC emitted light significantly affected the levels of MMP-2 in both females and males. Levels of TOS and NO were increased by LED, respectively by MP and LED exposure in female rats. The histopathological examination revealed no statistically significant differences in the ovaries and testes of rats across the different groups. Blue light exposure induces precocious puberty, by accelerating sexual maturation, and triggers the overproduction of MMPs that could promote organic alteration through tissue remodeling. Oxidative stress parameters were upregulated only in female rats, while cortisol levels were higher in male rats.

Standardization of color measurement in the medical photography in clinical practice

BACKGROUND: For many medical specialties, photography is a routine element of work. Environmental factors equally and significantly influence the interpretation of colour light perception and the quality of photographic recording. Standardization of conditions in medical photography is necessary for subsequent quantitative assessment of the postoperative skin scar by analysing colour coordinates in the RGB system. AIM: To determine the impact of illumination and shooting distance at colour coordinates when studying unaltered skin. METHODS: Five volunteers without any skin diseases and no make-up on their facial skin were taken in the study. Skin type by the Fitzpatrick scale was II–III. Digital photography was made with a mobile device camera at distance 30 cm from the subject. For each participant, a series of digital photographs was taken at a distance of 20, 30, 40, 50, 60, 70 cm from the light source. Colour coordinates in the RGB system were measured in the digital graphics editor Adobe Photoshop CS6. Statistical analysis of the obtained data was carried out using Microsoft Office Excel 2019, Phyton 3.11. RESULTS: The analysis of variance by the ANOVA method was used as a statistical analysis. In order to determine a statistically significant difference between the sets, Tukey HSD test was performed. A total of 1764 coordinates of three colours were subjected to statistical analysis (R=588, G=588, B=588). When constructing a heat map of the cross-correlation of the absolute values of each colour at each distance, taking into account the type of light source among themselves, the data had a strong direct correlation, regardless of the study area. When constructing a linear graph, coordinates of any of the zones were located on the same straight line. CONCLUSION: Photography conditions were experimentally determined under which the color interpretation of light is constant. Results of the study should be taken into account during medical photography and subsequent color assessment of postoperative skin scars.

Energy-Efficient and Smart Bicycle Lamps: A Comprehensive Review

In this review paper, information about bicycle lamp technical parameters is provided. The review is based on the searched Web of Science (WoS) and Scopus bibliographic databases and Transportation Research Information Services, which include references to books, technical reports, conference proceedings, and journal articles. This review showed that these papers about bicycle lighting legal rules in given countries are very easy to reach, but deep searching must be performed to find this research paper having the information about types of optical systems and light sources used in bicycle lamps. This research was conducted using PRISMA 2020 assumptions in the area of bicycle lighting technologies and innovations. The information about bicycle lamp technical parameters was obtained on the basis of the examination of technical documents and papers from high-impact journals. The author’s review shows that contemporary bicycle lamps are becoming increasingly smarter and more energy efficient, while also enhancing safety and comfort for cyclists on their routes in and beyond urban environments.

The Impact of Visual Digital Unit Exposure on Ocular Symptoms of Computer Vision Syndrome Among Selangor Office Workers

Objective: Computer Visual Syndrome (CVS) is a common condition characterized by a range of ocular symptoms resulting from excessive screen time. As visual digital unit (VDU) usage has skyrocketed across all age groups, CVS has become a prevalent issue in both personal and professional life. Therefore, this study aimed to investigate the association between the impact of VDU and ocular symptoms of CVS among office workers in Selangor. Material and Methods: In this cross-sectional study, 46 office workers completed a self-reported Computer Vision Syndrome (CVS) assessment using a questionnaire adapted from a previous study. The questionnaire includes 9 questions about ocular symptoms, rated on a 5-point scale: none, slight, moderate, severe, and very severe. Computer screen illumination was measured using a lux meter. To account for potential confounding factors, environmental conditions were also assessed. These included the number and type of light sources, window presence and size, window treatments, lighting fixture placement, and overall workspace cleanliness, following the guidelines on occupational safety and health for working with video display units by the Malaysia Department of Occupational Safety and Health.Results: Among all participants, the majority (93.5%) did not use anti-glare screen monitors and 20% had inadequate lighting with less than 450 lux. Of the respondents, 63% of the respondents reported experiencing eye strain and eye fatigue (60.9%) during work hours. Eye fatigue was the most commonly reported ocular symptom, with 24% of respondents experiencing it more than six times per week. Lighting reflector was found to be 3.5 times more prevalent to cause eye redness (odds ratio (OR)=3.50; 95% confidence interval (CI)=0.50–24.33). The likelihood of experiencing eye strain due to the absence of an anti-glare was 1.8 times higher and the absence of a lighting reflector increased the likelihood by 1.7 times. Conclusion: The alarmingly high prevalence of Computer Vision Syndrome (CVS) among office workers underscores the critical need for immediate and effective ergonomic interventions. This research is imperative to identify specific risk factors and develop targeted strategies to mitigate the detrimental effects of prolonged VDU use on ocular health.

Ocular Complication in Facial Aesthetic Laser and Light Treatments: A Comprehensive Review.

The increasing popularity of laser- and light-based esthetic treatments for facial rejuvenation has raised concerns regarding ocular safety. Although these procedures are generally considered safe and effective, there is a growing body of evidence highlighting the potential for ocular complications. This review aims to systematically analyze the types and mechanisms of ocular injuries associated with such treatments, as well as to evaluate preventive measures and management strategies. A comprehensive literature search was conducted using databases including MEDLINE, PubMed and Ovid for relevant studies published on clinical trials, diagnosis and treatment. Some papers were further reviewed using a double-blinding approach, varying sample sizes, control usage, randomization usage and objective endpoint measurements. All studies were classified according to the Oxford Centre for evidence-based medicine evidence hierarchy. Our review identified several types of ocular complications associated with facial laser or light treatments, including but not limited to conjunctival burns, corneal damage, retinal phototoxicity, and transient vision disturbances. The incidence of these complications varies significantly depending on the type of laser or light source employed, treatment parameters, and the anatomical proximity of the eyes to the treatment area. Factors such as inadequate protective measures, patient movement during the procedure, and the operator's experience were found to contribute to the risk of ocular injury. Strategies such as the use of appropriate eye protection, careful patient positioning, and thorough pre-treatment assessments were highlighted as essential preventive measures. Ocular complications, though rare, represent a significant risk in facial esthetic laser and light treatments. This review underscores the importance of awareness among practitioners regarding the potential ocular hazards and the implementation of robust safety protocols. Future research is needed to establish standardized guidelines to minimize risks and enhance patient safety in esthetic dermatological practices. Continued education and improved protective strategies will be essential in safeguarding ocular health as the field of esthetic treatments continues to evolve. This comprehensive review serves as an essential resource for practitioners, informing them of ocular risks, management options, and the need for vigilance to mitigate complications in clinical practice.

Development of Deep Ultraviolet LED Packaging

Deep ultraviolet light-emitting device (DUV-LED) package is a hotspot of growing concern for research scholars, it is through the LED semiconductor LEDs emit UVC band ultraviolet (typical wavelength 260 ∼ 280 nm), is a new type of healthy artificial light source, compared with the traditional UV light source mercury lamps, the DUV-LED has a wavelength of accurate and controllable, green. Due to the high-energy DUV-UV radiation capability, it has a strong bactericidal and inactivation effect on bacteria, viruses, and other microorganisms. In recent years, with the continuous progress of deep packaging technology, the optical efficiency and reliability of DUV-LEDs have been significantly improved. This paper summarizes the key technologies of DUV packaging, the performance of DUV-LEDs, and the application of DUV-LEDs, through the understanding of the packaging materials, packaging structure, packaging process, and so on to improve the performance of DUV-LEDs, so that it is better to apply to the market, which can be seen that the DUV-LEDs have a great prospect for development. Received: 27 February 2024 | Revised: 23 May 2024 | Accepted: 2 September 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available from the corresponding author upon reasonable request. Author Contribution Statement Jichen Shen: Conceptualization, Methodology, Formal analysis, Investigation, Resources, Data curation, Writing - original draft, Visualization. Tianqi Wu: Software. Jun Zou: Writing - review & editing, Supervision. Peng Wu: Validation. Yitao Liao: Project administration.

Construction of In2S3–In(OH)3–ZnS nanofibers for boosting photocatalytic hydrogen evolution

Construction of In2S3–In(OH)3–ZnS nanofibers for boosting photocatalytic hydrogen evolution

Effects of Antimicrobial photosensitizers of Photodynamic Therapy (PDT) to Treat Periodontitis.

Along with antimicrobial photosensitizers or antimicrobial photodynamic therapy (aPDT), Photodynamic therapy (PDT) is a therapeutic approach in which lasers and different photosensitizers (PSs) are used to eradicate periodontopathic bacteria in aggressive and chronic periodontitis. Periodontitis is a localized infectious disease caused by periodontopathic bacteria and can destroy bones and tissues surrounding and supporting the teeth. The aPDT system has been shown by in vitro studies to have high bactericidal efficacy. It was demonstrated that aPDT has low local toxicity, can speed up dental therapy, and is cost-effective. Several photosensitizers (PSs) are available for each type of light source which did not induce any damage to the patient and are safe. In recent years, significant advances have been made in aPDT as a non-invasive treatment method, especially in treating infections and cancers. Besides, aPDT can be perfectly combined with other treatments. Hence, this survey focused on the effectiveness and mechanism of aPDT of periodontitis by using lasers and the most frequently used antimicrobial PSs such as methylene blue (MB), toluidine blue ortho (TBO), indocyanine green (ICG), Malachite green (MG) (Triarylmethanes), Erythrosine Dyes (ERY) (Xanthenes dyes), Rose bengal (RB) (Xanthenes dyes), Eosin-Y (Xanthenes dyes), Radachlorin group and Curcumin. The aPDT with these PSs can reduce pathogenic bacterial loads in periodontitis. Therefore, it is clear that there is a bright future for using aPDT to fight microorganisms causing periodontitis.

Quantum Prism-Nano Source of Light with Dispersive Spectrum and Optical Upconversion.

A quantum prism, a new structure, consisting of many quantum wires with a diameter that gradually decreases from the base to the top, is the focus of our research. This distribution of quantum wires leads to a dispersive emitted spectrum. The red edge of the spectrum is determined by the band gap width of the bulk semiconductor, and the blue edge is determined by the quantum size of the excitons at the top of the prism. The PL spectrum of the silicon prismatic sample was excited by weak and strong light absorption. At weak absorption (hνex = 1.2 eV), the PL spectrum is located in the visible part of the spectrum, from 1.4 eV to 1.9 eV, with an energy higher than the band gap of the Si crystal. Such a "blue shift" of PL spectra by 0.7 eV is characteristic of the quantum confinement effect. It is a rainbow spectrum with an optical upconversion. The quantum prism is a new type of nano light source, as it replaces two elements in a conventional spectrometer: a light source and a dispersive element. These features enable to create a nano-spectrometer for measuring the absorption spectrum of individual molecules or viruses.

Retroreflective optical ISAC using OFDM: channel modeling and performance analysis.

In this Letter, we propose and investigate a retroreflective optical integrated sensing and communication (RO-ISAC) system using orthogonal frequency division multiplexing (OFDM) and corner cube reflector (CCR). To accurately model the reflected sensing channel of the RO-ISAC system, both a point source model and an area source model are proposed according to the two main types of light sources that are widely used. Detailed theoretical and experimental results are presented to verify the accuracy of the proposed channel models and evaluate the communication and sensing performance of the considered RO-ISAC system.

Combined Electrochemical Deposition and Photo-Reduction to Fabricate SERS-Active Silver Substrates: Characterization and Application for Malachite Green Detection in Aquaculture Water.

This research introduces a novel approach using silver (Ag) nanostructures generated through electrochemical deposition and photo-reduction of Ag on fluorine-doped tin oxide glass substrates (denoted as X-Ag-AgyFTO, where 'X' and 'y' represent the type of light source and number of deposited cycles, respectively) for surface-enhanced Raman spectroscopy (SERS). This study used malachite green (MG) as a Raman probe to evaluate the enhancement factors (EFs) in SERS-active substrates under varied fabrication conditions. For the substrates produced via electrochemical deposition, we determined a Raman EF of 6.15 × 104 for the Ag2FTO substrate. In photo-reduction, the impact of reductant concentration, light source, and light exposure duration were examined on X-Ag nanoparticle formation to achieve superior Raman EFs. Under optimal conditions (9.0 mM sodium citrate, 460 nm blue-LED at 10 W for 90 min), the combination of blue-LED-reduced Ag (B-Ag) and an Ag2FTO substrate (denoted as B-Ag-Ag2FTO) exhibited the best Raman EF of 2.79 × 105. This substrate enabled MG detection within a linear range of 0.1 to 1.0 µM (R2 = 0.98) and a detection limit of 0.02 µM. Additionally, the spiked recoveries in aquaculture water samples were between 90.0% and 110.0%, with relative standard deviations between 3.9% and 6.3%, indicating the substrate's potential for fungicide detection in aquaculture.

A non-contact colour correction system on mobile display under various light sources

A non-contact colour correction system on mobile display under various light sources

Perancangan Sistem Smart Lighting Menggunakan Arduino

<p><em>In Indonesia, many users use electricity for light needs. There are two types of light sources, there is man-made light and there is natural light. The light source also only has two methods, namely turning it on and turning it off. No one can set the conditions for the light, in other words it has to be done manually. Therefore, the cause of electricity waste is manual use. In this case, researchers aim to create a control system for this light. With a system that is able to control the light control system automatically. Through a PIR sensor which will control movement to turn on the lights. The way it works is very easy, if there is movement the light will turn on. </em></p><p><em> </em></p><p><em>Keywords: Arduino, System, Light</em></p>

Harnessing spin and orbital angular momentum light for optimal algae growth

The present study investigated the difference in transmittance of light carrying opposite spin angular momentum (SAM) and orbital angular momentum (OAM) through chlorella algal fluid with varying concentrations and thicknesses. Our results indicate that, under specific conditions, right-handed light sources exhibit higher transmittance in the algal fluid compared to left-handed light sources. Furthermore, we observed that light with OAM also demonstrated higher transmittance than other types of light sources, leading to faster cell density growth of Chlorella. Interestingly, we also discovered that light with OAM stimulates Chlorella to synthesize more proteins. These findings provide different insights for selecting appropriate light sources for large-scale algae cultivation, and may facilitate the realization of carbon peaking and carbon neutrality in the future.