Light Intensity Distribution Research Articles

Does the distribution of light intensity within the barn impact broiler production and welfare?

ABSTRACT 1. The objective of this study was to determine if rearing broilers under variable light intensity (VLI) impacted their welfare or productivity. 2. Ross 308 broilers (n = 7,256) were reared until 35 d of age and exposed to a uniform intensity of 10 lux (CON) or VLI with low intensity areas of 2–5 lux proximal to the walls and high intensity areas of 84–133 lux proximal to feeders. 3. The data were analysed as a complete randomised design using an analysis of variance. Significance was declared when p ≤ 0.05. 4. Applying VLI resulted in increased feed intake early in life but had no impact on body weight. Overall efficiency was improved in the CON treatment. Mortality diagnoses of skeletal problems were reduced under VLI. Treatment had no impact on footpad, hock or gait score, heterophil to lymphocyte ratio or melatonin concentration. Birds performed certain behaviours in specific locations within the room, independent of light intensity treatment. 5. In conclusion, raising broilers under VLI had little impact on production or most welfare parameters assessed in this study. However, satisfying the bird’s preference for different light intensities may improve welfare.

Beam quality measurement and image analysis of RF optical emission system

With the development of radio-over-fiber (ROF), beam quality is also an important parameter in evaluating ROF systems. Therefore, this paper selects the low-frequency to very high frequency (VHF) direct modulated optical emission system to verify its feasibility and excellent performance. It then analyzes the beam quality and image processing. In this paper, MATLAB is selected for the theoretical simulation, then CMOS is used to collect light spots, RayCiV2.5 is used to Gaussian fit the light field intensity distribution, and finally the ideal and actual light spot parameters are compared. Due to the influence of noise, this paper also preprocessed the image by brightness adjustment, filtering, edge fitting, etc. It proposed a fast two-sided filtering algorithm, which obtained a high peak signal-to-noise ratio (PSNR) and strong applicability. The results show that the edge-mode rejection ratio is as high as 33.6 dB, the beam quality is good, and it can be well applied in ROF. The M2 factor is 2.75, the optical field intensity Gaussian fit is 99.8 %, and the signal-to-noise ratio (SNR) is as high as 54.7 dB. Moreover, the image is robust after fast bilateral filtering.

Quantifying Bioluminescent Light Intensity in Breaking Waves Using Numerical Simulations

AbstractBreaking‐wave induced bioluminescence is a critical component of the biogeochemical process in the ocean. Understanding bioluminescence is important for monitoring red tides caused by bioluminescent microorganisms. In this study, we present the first numerical effort to quantify bioluminescent light intensity based on high‐fidelity direct numerical simulations of breaking waves and a quantitative bioluminescent model. The dynamics of breaking waves are extensively validated through comparison with existing studies. We find that the time‐averaged and Lagrangian‐averaged shear stress saturates as surface tension effects decrease and wave steepness increases. The spatial distribution of light intensity correlates with the wave crest overturning and air bubbles generated in plunging breakers. Furthermore, we observe that the maximum light intensity asymptotically approaches the emission of single cells, suggesting the potential for cost‐effective prediction models in future studies.

Modeling and application of array light sources in ultraviolet communication systems

Reliable communication over long distances using ultraviolet (UV) light is challenging due to the strong scattering and atmospheric absorption of UV light. However, with advancements in UV LED technology, the performance of transmitters can be significantly enhanced by employing an array of light sources, which improves the overall quality of communication. Despite these advancements, the impact of various array configurations — such as shape, quantities, and other parameters — on light intensity distribution and UV optical communication remains largely unexplored. In this work, we first modeled the light intensity distribution of arrayed light sources with varying shapes, quantities, and other parameters. We improved the traditional Monte Carlo method to better accommodate these distributions, enabling more accurate simulations. Subsequently, we obtained simulation results for different array configurations. Building on these findings, we developed a UV LED array communication system that achieved a bit error rate (BER) of 10−6 for information transmission over a distance of 500 m. This research provides valuable insights into the long-distance transmission capabilities of UV light using arrayed light sources.

Fractional Talbot Lithography for Predesigned Large-Area Liquid-Crystal Alignment

To address the increasing demands for cost-effective, large-area, and precisely patterned alignment of liquid crystals, a fractional Talbot lithography alignment technique was proposed. A light intensity distribution with a double spatial frequency of a photomask could be achieved based on the fractional Talbot effect, which not only enhanced the resolution of lithography but also slashed system costs with remarkable efficiency. To verify the feasibility of the alignment method, we prepared a one-dimensional polymer grating as an alignment layer. A uniform alignment over a large area was achieved thanks to the perfect periodicity and groove depth of several hundred nanometers. The anchoring energy of the alignment layer was 1.82 × 10−4 J/m2, measured using the twist balance method, which surpassed that of conventional rubbing alignment. Furthermore, to demonstrate its ability for non-uniform alignment, we prepared polymer concentric rings as an alignment layer, resulting in a liquid-crystal q-plate with q = 1 and α0 = π/2. This device, with a wide tuning range (phase retardation of ~6π @ 633 nm for 0 to 5 V), was used to generate special optical fields. The results demonstrate that this approach allows for the uniform large-area orientation of liquid-crystal molecules with superior anchoring energy and customizable patterned alignment, which has extensive application value in liquid-crystal displays, generating special optical fields and intricate liquid-crystal topological defects over a large area.

Model based optimization for refractive index mismatched light sheet imaging

Selective plane illumination microscopy (SPIM) is an optical sectioning imaging approach based on orthogonal light pathways for excitation and detection. The excitation pathway has an inverse relation between the optical sectioning strength and the effective field of view (FOV). Multiple approaches exist to extend the effective FOV, and here we focus on remote focusing to axially scan the light sheet, synchronized with a CMOS camera’s rolling shutter. A typical axially scanned SPIM configuration for imaging large samples utilizes a tunable optic for remote focusing, paired with air objectives focused into higher refractive index media. To quantitatively explore the effect of remote focus choices and sample space refractive index mismatch on light sheet intensity distributions, we developed an open-source computational approach for integrating ray tracing and field propagation. We validate our model’s performance against experimental light sheet profiles for various SPIM configurations. Our findings indicate that optimizing the position of the sample chamber relative to the excitation optics can enhance image quality by balancing aberrations induced by refractive index mismatch. We validate this prediction using a home-built, large sample axially scanned SPIM configuration and calibration samples. Our open-source, extensible modeling software can easily extend to explore optimal imaging configurations in diverse light sheet imaging settings.

Analytical form of the refocused images from correlation plenoptic imaging

Correlation plenoptic imaging (CPI) is emerging as a promising approach to light-field imaging (LFI), a technique for concurrently measuring light intensity distribution and propagation direction of light rays from a 3D scene. LFI thus enables single-shot 3D imaging, offering rapid volumetric reconstruction. The optical performance of traditional LFI, however, is limited by a micro-lens array, causing a decline in resolution as 3D capabilities improve. CPI overcomes these limitation by measuring photon number correlations on two photodetectors with spatial resolution, in a lenslet-free design, so that the correlation function can be decoded in post-processing to reconstruct high-resolution images. In this paper, we derive the analytical expression of CPI images reconstructed through refocusing, addressing the previously unknown mathematical relationship between object shape and its final image. We show that refocused images are not limited by numerical aperture-induced blurring, as in conventional imaging. Rather, the image features of CPI can be explained through an analogy with imaging systems illuminated by spatially coherent light.

Multi-physics field coupling analysis of in-situ laser-assisted micro-imprinting of micro tapered holes

Micro tapered holes find extensive use in various domains including detection, infusion, lighting, etc. This study has investigated the deformation behavior and machining quality of micro-tapered holes generated by in-situ laser-assisted micro-imprinting (In-LAI) using a diamond indenter. The effects of in-situ laser-assisted action on the edge bulge at the inlet, residual stress at the outlet, and microcracks at outlet of a micro tapered hole have been analyzed by using a coupled optical-thermal-force multiphysics field model. Replacing conventional Gaussian heat sources with laser light intensity distributions obtained from optical-thermal coupling model analysis. Compared to ambient temperature, Laser intensity at the tip of the diamond indenter under operating conditions decreased by 11.59 %. The in-situ laser-assisted action has reduced the force by 13 %, reduced the edge bulge at the inlet of the micro tapered hole by 57.3 %, increased the residual compressive stress at the outlet by 47.6 %, and suppressed the generation of microcracks at the outlet. The results show that In-LAI is an effective technique for micro-tapered hole machining, and the multi-physical field coupling research method also provides implications for other in-situ laser-assisted machining (In-LAM) techniques.

Investigation on concentration detection of turbid solution based on hemisphere sample cell and multidimensional spectroscopy

The study developed a hemisphere sample cell and constructed a multidimensional spectroscopy acquisition system to enhance the accuracy of detecting turbid solution with scattering properties. The system simultaneously captures absorption and scattering information from the tested samples. Monte Carlo simulation was employed to model the transmission light intensity distribution data from sample cells of various shapes. It was found that the hemisphere sample cell increases the dimensionality of transmission light intensity information and enables the acquisition of more scattering-related data. Furthermore, 46 samples of intralipid-20% solution with varying concentrations were examined. Models were constructed using partial least squares (PLS) regression with one-dimensional and two-dimensional light intensity distribution data. The results indicate that the model using two-dimensional light intensity distribution data significantly outperforms the model using one-dimensional data, reducing the root mean square error by 39.96% and increasing the correlation coefficient by 0.332%. Experimental results demonstrate that the multidimensional spectroscopic modeling method employing the hemisphere sample cell can significantly enhance the accuracy and speed of detecting chemical composition concentrations in turbid solution.

Optimization design of low-carbon building thermal energy based on optical sensing and virtual reality image scene reconstruction

With the intensification of global climate change and energy crisis, the design of low-carbon buildings has gradually become a research hotspot in the field of architecture. Effective thermal optimization design not only reduces energy consumption, but also improves the comfort and sustainability of the building. This study aims to explore the optimization design of low-carbon building heat energy based on light sensing technology, combined with virtual reality image scene reconstruction, to provide an innovative design method to achieve intelligent management and optimization of building heat energy. Through the introduction of light sensing technology, the light intensity and heat distribution inside and outside the building are monitored, and the combination of data analysis and model simulation is used to evaluate the heat use of the building. On this basis, virtual reality scenes are constructed to reconstruct the heat flow and distribution of buildings, providing designers with intuitive visualization tools. The research shows that the design method based on light sensing can effectively identify the areas of heat waste in the building, and reduce the energy consumption of the building by optimizing the window layout, adding greening and improving the thermal management system. Virtual reality image scene reconstruction makes the design process more intuitive, helps the design team to quickly adjust and optimize, and improves the efficiency and accuracy of the design.

Light footprint of microalgae cultivation system addressed by modified Cornet model

The cultivation of microalgae is significantly influenced by light intensity and utilization efficiency. This study developed a modified Cornet (M−Cornet) model to assess the distribution of light intensity and flux in microalgae cultivation systems. Algal biofilm cultivation represents a more concentrated approach of algal suspension cultivation. Both follow the M−Cornet model and exhibit the same growth rates when cultured under identical conditions. Algal pigments and morphologies greatly impact the light absorption and scattering, resulting in light attenuation in intensity, penetration distance and light flux distribution. Algae varieties exhibit diverse light flux characteristics. 37% − 90% of the incident light is absorbed, of which, 80% to 90% is dissipated as heat. 10% to 63% of the incident light is scattered off the photobioreactor. The overall light utilization efficiency ranges 6% to 13%. The light footprint using the M−Cornet model offers valuable insights for photobioreactors designing and cultivation operating.

Assessing the 3D resolution of refocused correlation plenoptic images using a general-purpose image quality estimator

Correlation plenoptic imaging (CPI) is emerging as a promising approach to light-field imaging (LFI), a technique enabling simultaneous measurement of light intensity distribution and propagation direction from a scene. LFI allows single-shot 3D sampling, offering fast 3D reconstruction for a wide range of applications. However, the array of micro-lenses typically used in LFI to obtain 3D information limits image resolution, which rapidly declines with enhanced volumetric reconstruction capabilities. CPI addresses this limitation by decoupling the measurement of the light field on two photodetectors with spatial resolution, eliminating the need for micro-lenses. 3D information is encoded in a four-dimensional correlation function, which is decoded in post-processing to reconstruct images without the resolution loss seen in conventional LFI. This paper evaluates the tomographic performance of CPI, demonstrating that the refocusing reconstruction method provides axial sectioning capabilities comparable to conventional imaging systems. A general-purpose analytical approach based on image fidelity is proposed to quantitatively study axial and lateral resolution. The analysis fully characterizes the volumetric resolution of any CPI architecture, offering a comprehensive evaluation of its imaging performance.

Development And Application Of A New Visualization Technique Using Photochromism For Transport Process Of Lubricating Oil Around The Engine Piston

A new visualization technique using photochromism for the movement of oil film was developed and applied to an optical gasoline engine. A photochromic dye was dissolved in the oil and an arbitrary position of the oil film was illuminated by UV laser light, which makes a marker in the oil film via a photochromic reaction. The lifetime of color change by photochromism is relatively long and therefore, by tracking the movement of a marker makes it possible to visualize the movement of oil film directly. The color density was quantified based on the absorbance calculated from images taken before and after coloring in two wavelengths. Through the experimental and theoretical considerations, it was confirmed that the calculated absorbance is effective in reducing a noise originated by the color, the shape of the piston surface, the temporal variation of oil film thickness and the illuminating light intensity distribution. Furthermore, the value of the absorbance is in a very good linear relationship with the oil film thickness. This technique was applied to an optical gasoline engine and confirmed the availability of this technique. In the top land of piston surface, the oil film between the piston and cylinder liner was separated and the majority of the oil is at the piston surface and moved with the piston motion. The oil film thickness on the cylinder liner was very thin. On the contrary, at the piston skirt region, a wider region of the oil film is connected between the linear and the piston skirt. However, there are regions where the oil film between the liner and the skirt is separated by cavitation and the majority of the oil film is on the piston skirt. The change of the flow direction by the operating condition, i.e., the throttle condition, was able to clearly visualize, though the movement of oil film on the piston surface was very slow in normal case. The relatively fast complexed flow for opposite direction was also able to visualize by this technique.

Nanowatt all-optical 3D perception for mobile robotics.

Three-dimensional (3D) perception is vital to drive mobile robotics' progress toward intelligence. However, state-of-the-art 3D perception solutions require complicated postprocessing or point-by-point scanning, suffering computational burden, latency of tens of milliseconds, and additional power consumption. Here, we propose a parallel all-optical computational chipset 3D perception architecture (Aop3D) with nanowatt power and light speed. The 3D perception is executed during the light propagation over the passive chipset, and the captured light intensity distribution provides a direct reflection of the depth map, eliminating the need for extensive postprocessing. The prototype system of Aop3D is tested in various scenarios and deployed to a mobile robot, demonstrating unprecedented performance in distance detection and obstacle avoidance. Moreover, Aop3D works at a frame rate of 600 hertz and a power consumption of 33.3 nanowatts per meta-pixel experimentally. Our work is promising toward next-generation direct 3D perception techniques with light speed and high energy efficiency.

Dual light source compensation method for improving the quality of LC-SLM holographic displays.

The inherent "grid" effect of LC-SLM in holographic displays can lead to issues such as the presence of zero-order spots and multi-level diffraction images, resulting in a decrease in the quality of reconstructed images. In this Letter, a dual light source compensation method is proposed to address this problem. By analyzing the influence of the LC-SLM "grid" effect on the diffraction field and the rule of change of light intensity distribution and position of the reconstructed image, the dual light source is introduced on the basis of the rule of change of energy distribution at the symmetric position of the reconstructed image so as to compensate for the quality of the display results. The results show that the method not only avoids the influence of zero-order spot and multi-level diffraction image on the holographic display results but also especially highlights that the uniformity of light energy distribution of the reconstructed image is greatly improved, which provides a reference for LC-SLM to perform a higher-quality holographic display.

Planar and ridged waveguide preparation on erbium pre-implanted fused silica by multi-energy helium ion implantation and femtosecond laser ablation

Ion implantation stands as a highly competitive technique for fabricating optical waveguide structures within photoelectric materials. In this work, both planar and ridge waveguides have been successfully realized on fused silica. The fabrication process begins with the implantation of erbium ions into fused silica, utilizing an energy of 400 keV and a fluence of 5×1015ions/cm2 to produce a fluorescence effect. Following this, helium ions are implanted at varying energies −450, 500, and 550 keV-with a consistent fluence of 3.2×1016ions/cm2 to create a planar waveguide structure. Subsequently, the ridge waveguide is meticulously prepared through the application of laser ablation, leveraging the pre-existing planar waveguide as a foundation. The guide mode of the planar waveguide is characterized at a wavelength of 632.8 nm using the prism coupling method. Additionally, the near-field light intensity distribution at the same wavelength is assessed via the end-face coupling technique and further analyzed using the finite-difference beam propagation method. To substantiate the practical utility of these waveguides, measurements of the propagation loss and fluorescence properties are conducted.

Numerical simulation of deep ultraviolet LED, micro-LED, and nano-LED with different emission wavelengths based on FDTD.

The current low external quantum efficiency (EQE) of deep ultraviolet (DUV) LEDs and micro-LEDs is largely attributed to their low light extraction efficiency (LEE). To address this issue and increase the LEE of DUV devices, various strategies such as reducing size, modifying surface with nanostructures and roughening substrates have been proposed. While some studies have investigated the effects of nanopillar and size on DUV LED, there remains a lack of systematic research on the LEE enhancement mechanism across different wavelengths and sizes of DUV LEDs, micro-LEDs, and nano-LEDs. Therefore, in this study, we employed the numerical simulation method to explore the LEE, near-field intensity distribution, and far-field light intensity distribution from various angles for DUV LEDs, micro-LEDs, and nano-LEDs with wavelengths of 255 nm, 260 nm, and 275 nm, respectively. Our findings reveal a significant improvement in the LEE of DUV nano-LEDs and micro-LEDs, accompanied by reduced divergence angles. Moreover, we observe that longer wavelengths correspond to higher LEE values for devices with similar size. This enhancement in LEE is attributed to factors such as increased sidewall emission and reduced p-GaN absorption. Our investigation indicates that as the size of the DUV device decreases, the sidewall LEE for both transverse electric (TE) and transverse magnetic (TM) modes increases, with TM mode exhibiting a larger enhancement. This enhancement is mainly attributed to the reduction of total reflection within the DUV LEDs and micro-LEDs resulting from size reduction. Despite this, TE mode remains the main contributor to overall LEE. Additionally, our study reveals a reduction in p-GaN absorption of DUV light with decreasing device size, further contributing to the enhancement of LEE in DUV micro-LEDs and nano-LEDs. The increased LEE and reduced divergence angles of small-size DUV micro-LEDs and nano-LEDs not only promote lower power consumption but also enable easier optical system coupling. Consequently, these advancements have significant potential in optical wireless communication, charge management and high-precision lithography.

An asymmetric road lighting concept: Probeam

An asymmetric road lighting concept known as Probeam is investigated in this study for energy efficiency, contrast and visibility of vertical objects and road markings in highway lighting. Calculations based on road lighting standards, road surface and markings reflection characteristics and typical Dutch highway geometry, reveal that Probeam lighting improves the average visibility of objects and road markings over symmetrical lighting, however, with a 14% increase in luminous flux as per current road lighting standards. This increase in luminous flux is attributed to the symmetrical lighting’s advantage in specular road surface reflection, leading to a reduction in the Counterbeam lobe size in the light intensity distribution when designed to meet the current road luminance requirement. Notably, by designing the Probeam luminaire to match symmetrical lighting’s average visibility of vertical objects, for removing the road luminance requirement and dimming the luminaire, energy consumption is reduced by 52%. Halving the Probeam luminaire’s mounting height leads to an impressive 82% energy savings. The study highlights the possibility of a balance in energy use and road safety using the Probeam concept, considering advancements in road luminaires and retroreflective materials. Due to glare, the relevance of the proposed Probeam concept is restricted to one-directional traffic on highways.

Investigation of collagen reconstruction mechanism in skin wound through dual-beam laser welding: Insights from multi-spectroscopy, molecular dynamics simulation, and finite element multiphysics simulation

Since the mechanism underlying real-time acquisition of mechanical strength during laser-induced skin wound fusion remains unclear, and collagen is the primary constituent of skin tissue, this study investigates the structural and mechanical alterations in collagen at temperatures ranging from 40 °C to 60 °C using various spectroscopic techniques and molecular dynamics calculations. The COMSOL Multiphysics coupling is employed to simulate the three-dimensional temperature field, stress-strain relationship, and light intensity distribution in the laser thermal affected zone of skin wounds during dual-beam laser welding process. Raman spectroscopy, synchronous fluorescence spectroscopy and circular dichroism measurement results confirm that laser energy activates biological activity in residues, leading to a transformation in the originally fractured structure of collagen protein for enhanced mechanical strength. Molecular dynamics simulations reveal that stable hydrogen bonds form at amino acid residues within the central region of collagen protein when the overall temperature peak around the wound reaches 60 °C, thereby providing stability to previously fractured skin incisions and imparting instantaneous strength. However, under a 55 °C system, Type I collagen ensures macrostructural stability while activating biological properties at amino acid bases to promote wound healing function; this finding aligns with experimental analysis results. The COMSOL simulation outcomes also correspond well with macroscopic morphology after laser welding samples, confirming that by maintaining temperatures between 55 °C–60 °C during laser welding of skin incisions not only can certain instantaneous mechanical strength be achieved but irreversible thermal damage can also be effectively controlled. It is anticipated that these findings will provide valuable insights into understanding the healing mechanism for laser-welded skin wounds.

Mode-dependent analysis of a fiber optic curvature sensor with sensitive zone

In this paper, mode-dependent analysis of fiber optic curvature sensor with precision machined structural imperfections (teeth) as sensitive zone is conducted. Using controlled input or light source launching conditions sensor response is measured for different modes excited in the multimode optical fiber. Study shows that as curvature changes there is significant difference in how sensitive zone affects low and high order modes propagating through the fiber. Obtained measurement results provide further insight into FOCS response and open possibilities for development of new measurement approaches which represent a significant step forward for FOCS based measurement systems. Guidelines for maximizing sensor sensitivity, increasing measurement reliability and even avoiding intensity based measurement by measuring changes in the width of the sensor’s output light intensity distribution are discussed in this work.