light sources are crucial in laser displays, directly influencing color gamut performance and speckle characteristics. Besides broadening the laser spectral width for speckle suppression, alternative blending schemes ...
详细信息
light sources are crucial in laser displays, directly influencing color gamut performance and speckle characteristics. Besides broadening the laser spectral width for speckle suppression, alternative blending schemes for light sources have been proposed to address the challenges associated with spectral broadening. Although these light source configurations enhance speckle suppression, they negatively impact the monochromaticity of the primary colors. By comprehensively considering the speckle suppression effect and color gamut performance, the evaluation factor F has been proposed to determine the optimal configurations of light sources. The optimal spectral bandwidth and blending ratio were obtained by utilizing the evaluation factor. Furthermore, considering the luminance limitations, the scenario with a significant luminance difference between lasers and LEDs was discussed. In the laser-LED blending scheme constrained by luminance limitations, the optimal blending ratios of red and blue primary colors were determined, while green LED was not advisable. Moreover, the speckle suppression effect of laser-LED blending scheme was experimentally validated and found to be influenced by screen scattering. These findings can provide theoretical guidance for the evaluation and configuration of light sources in laser displays.
The evolution of low wattage metal halide lamps is used to illustrate the product life cycle of light sources from conception, through commercial launch to maturity, decline and replacement by LED-based sources. Simil...
详细信息
The evolution of low wattage metal halide lamps is used to illustrate the product life cycle of light sources from conception, through commercial launch to maturity, decline and replacement by LED-based sources. Similar examples are presented for incandescent and fluorescent light sources.
The Twyman-Green interferometer, as a representative type of interferometric structure, possesses unique advantages in the field of interferometry due to its adjustable single optical path characteristic. However, usi...
详细信息
The Twyman-Green interferometer, as a representative type of interferometric structure, possesses unique advantages in the field of interferometry due to its adjustable single optical path characteristic. However, using a laser as the light source for the Twyman-Green interferometer, with its long coherence length, can result in noisy fringes when measuring planar elements, including multiple surface interference fringes and speckle noise. To address these issues, this paper proposes the use of broadband extended light source as the coherent light source in the Twyman-Green interferometer to achieve short coherent source illumination, thereby eliminating interference fringes and coherent noise. This paper theoretically derives the coherence characteristics of broadband extended light sources and, in particular, quantitatively analyzes the influence of the thickness difference of glass in the Twyman-Green dual optical paths on the contrast of the interference fringe. The corresponding theoretical expressions for interference intensity are derived, and the validity of these theoretical findings is demonstrated through simulation analysis and experimental verification. This innovative research, to our knowledge, significantly supplements the existing coherence theory of light sources, offering substantial theoretical research insights and practical engineering applications. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
We have realized a compact optical particle counter utilizing enhancement of light scattering within a high finesse Fabry-Perot optical cavity. In contrast with laser-based approaches such as cavity ringdown spectrosc...
详细信息
We have realized a compact optical particle counter utilizing enhancement of light scattering within a high finesse Fabry-Perot optical cavity. In contrast with laser-based approaches such as cavity ringdown spectroscopy, we use the light stream from superluminescent and light-emitting diodes that have no longitudinal coherence. This eliminates the vibration sensitivity that is typical of laser-based cavity methods. The use of the transmission mode of detection allows us to reduce the cavity mirror separation to below 1 cm, with no obvious limit to miniaturization. Typical light scattering instruments are larger, in part due to their sensitivity to background signals from the light source. Our approach paves the way toward what we believe to be is a new generation of compact and portable instruments. A simultaneous comparison of the scattering signals with a commercial particle counter suggests that our cavity may be sensitive to ultrafine particles below 300 nm diameter, which are typically not recorded in such counters. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
The joint expertise of ANL and FNAL has led to the production of Nb3Sn undulator magnets in operation in the ANL Advanced Photon Source (APS). These magnets showed performance reproducibility close to the short sample...
详细信息
The joint expertise of ANL and FNAL has led to the production of Nb3Sn undulator magnets in operation in the ANL Advanced Photon Source (APS). These magnets showed performance reproducibility close to the short sample limit, and a design field increase of 20% at 820 A. However, the long training did not allow obtaining the expected 50% increase of the on-axis magnetic field with respect to the similar to 1 T produced at 450 A current in the ANL NbTi undulator. To address this, 10-pole long undulator prototypes were fabricated, and CTD-101K was replaced as impregnation material with TELENE, an organic olefin-based thermosetting dicyclopentadiene resin produced by RIMTEC Corporation, Japan. Training and magnet retraining after a thermal cycle were nearly eliminated, with only a couple of quenches needed before reaching short sample limit at over 1,100 A. TELENE will enable operation of Nb3Sn undulators much closer to their short sample limit, expanding the energy range and brightness intensity of light sources. TELENE is Co-60 gamma radiation resistant up to 7-8 MGy, and therefore already applicable to impregnate planar, helical and universal devices operating in lower radiation environments than high energy colliders.
Colour discrimination is a crucial research topic in lighting quality studies. Till now, various experimental methods have been widely adopted. Those methods based on the traditional colour-discrimination framework pr...
详细信息
Colour discrimination is a crucial research topic in lighting quality studies. Till now, various experimental methods have been widely adopted. Those methods based on the traditional colour-discrimination framework primarily focused on observers' ability to perceive discernible colour differences while neglecting the impact of noise and the corresponding possibility of false alarms. In this study, signal detection theory (SDT) was introduced to enhance the rationality of the experimental design and data analysis of the current methodology. The effects of various contextual factors on colour discrimination were systematically investigated under multiple light sources by three groups of psychophysical experiments. The results indicated that compared to traditional methods, the SDT framework largely incorporated previous findings and revealed new discoveries. Separating the colour discrimination process into sensory sensitivity and decision-making criteria provides a deeper explanation for the human colour discrimination performance under various experimental conditions. Additionally, by controlling the experimental set-ups, we demonstrated that the effect of lighting on observers' sensitivity and decision criterion could be manipulated. These findings provide strong evidence for the advantages of the SDT framework when investigating the colour discrimination process.
As solar power usage is increasing nowadays, performance tests have become one of the most important topics in order to guarantee the security of photovoltaic tools. For photovoltaic panels to become efficient, there ...
详细信息
As solar power usage is increasing nowadays, performance tests have become one of the most important topics in order to guarantee the security of photovoltaic tools. For photovoltaic panels to become efficient, there is need for health testing of all materials and technologies used in the production of the panels in electrical and optical aspects. Thus, when future energy standards are considered, it is imperative to use solar simulators that obtain near real sunlight spectrum values. The most important components of solar simulators used in photovoltaic panel tests are light sources. In this study, solar simulators' were classified based on the light sources they use, and their history and technological development were investigated in line with the literature. Within the scope of this study, carbon arc lamps, sodium vapor lamps, argon arc lamps, quartz-tungsten halogen lamps, mercury xenon lamps, xenon arc, xenon flash lamps, metal halide lamps, LED and super continuum laser light sources were investigated. Additionally, to compare spectral deficiency among these light sources and solar simulators, multiple light sourced solar simulators were also covered under a separate title.
A class of random sources producing far fields self-splitting intensity profiles with variable spacing between the x and y directions is introduced. The beam conditions for ensuring the sources to generate a beam are ...
详细信息
A class of random sources producing far fields self-splitting intensity profiles with variable spacing between the x and y directions is introduced. The beam conditions for ensuring the sources to generate a beam are derived. Based on the derived analytical expression, the evolution behavior of the beams produced by these families of sources in free space and turbulence atmospheric are explored and comparatively analyzed. By changing the modulation parameters n and m, the degree of coherence of Gaussian Schell-model source in the x and y directions are modulated respectively, and then the number of splitting beams and the spacing between splitting beams can be adjusted. It is illustrated that the self-splitting intensity profile is stable when beams propagate in free space, but they eventually transformed into a Gaussian profiles when it passes at sufficiently large distances from its source through the turbulent atmosphere. (C) 2014 Optical Society of America
The requirements on light sources for double resonance and level crossing spectroscopy are reviewed. A modern version of the Cario–Löchte–Holtgreven flow lamp is described and its performance for a number of el...
详细信息
The requirements on light sources for double resonance and level crossing spectroscopy are reviewed. A modern version of the Cario–Löchte–Holtgreven flow lamp is described and its performance for a number of elements is compared with that of sealed-off electrodeless discharge lamps and Schüler-type hollow cathode sources. None of these sources is useful under all circumstances. The electrodeless lamp is particularly effective in the case of the group IIb intercombination lines. The high atomic density available in the flow lamp makes it useful for partially forbidden resonance lines for a number of chemical species including highly reactive metals, such as Ca. The hollow cathode lamp is well suited to the fully allowed resonance lines of a wide range of elements including highly refractory metals.
Planar, scalar, optical Schell-model, and quasi-homogeneous sources with correlations that are Fourier transforms of multi-Gaussian functions are introduced. It is demonstrated that far fields produced by these famili...
详细信息
Planar, scalar, optical Schell-model, and quasi-homogeneous sources with correlations that are Fourier transforms of multi-Gaussian functions are introduced. It is demonstrated that far fields produced by these families of sources carry interesting characteristics, being flatlike with adjustable steepness of the edge. Beam conditions for such sources are also derived. (C) 2012 Optical Society of America
暂无评论