Application Of Laser Light Research Articles

Tailoring thermal behavior and luminous performance in LuAG:Ce films via thickness control for high-power laser lighting applications

Tailoring thermal behavior and luminous performance in LuAG:Ce films via thickness control for high-power laser lighting applications

Optical properties of Ce: GdYAG phosphor in glass with high quality LAS glass system and its application in laser illumination

Nowdays, the demand for high-power laser lighting applications is on the rise, however, phosphor in glass (PiG) prepared using conventional glass systems often experience damage under intense laser irradiation. To tackle this issue, we introduce a novel LAS glass system for phosphor encapsulation to create PiG, and by utilizing a spray coating technique, we blend PiG with high thermal conductivity sapphire to obtain phosphor in glass film (PiF), effectively improving laser irradiation resilience and optical characteristics. In this study, a novel LAS glass system (SiO2–Li2CO3–MgO–Al2O3–CaO–P2O5–K2O–ZrO2–Na2O) was utilized to encapsulate Ce:GdYAG phosphors to prepare a series of PiG and PiF. The glass system exhibits multi-directional interlocking lithium disilicate crystals, significantly enhancing the glass's strength and fracture toughness. There is no apparent interface reaction between the glass system and the phosphors, indicating effective protection of the phosphor particles. The PiF sample demonstrates a minor decrease of 5.2 % in internal quantum efficiency compared to the original phosphor, while boasting a high thermal conductivity of 7.4 W m−1 K−1. Notably, the optimized PiF shows remarkable enhancements with a saturation threshold of 4.37 W mm−2, surpassing PiG (1.668 W mm−2), and achieving LFmax of 424.41 lm and LEmax of 147.16 lm W−1. It features a high color rendering index (CRI) of 68.7 and low color correlated temperature (CCT) of 3646 K, significantly improving laser irradiation resistance and optical quality, making it a promising warm yellow laser illumination converter for diverse lighting applications.

An experimental study on the application of “blue” (λ = 450 nm) laser light to remove pigmented skin formations

Objective. Pigment benign skin formations, including pigment spots, nevi and congenital giant pigment nevi (CGPN) are pathological skin formations located in its various layers, consisting of a cluster of melanocytes – cells containing the pigment melanin. CGPN are a special psychological and medical problem associated with extensive unaesthetic changes in the skin and with changed appearance of the patient Currently, there are numerous methods for treating pigmented skin formations, including CGPN. But all them are often ineffective and lead to unsatisfactory clinical and aesthetic results, while the incidence of complications sometimes reaches 41 % of cases in the form of scarring and recurrences. In this regard, the problem of effective and correct treatment of them continues to be relevant and requires further research in this direction.Purpose. To experimentally substantiate the effectiveness of application of laser light with wavelength λ = 450 nm for improving outcomes of treatment of pigmented skin formations, including CGPN, in children.Materials and methods. In the present trial, the researchers used laser light of “blue” spectral range (λ = 450 nm) with the absorption peak close to melanin, hemoglobin and oxyhemoglobin. Such light is generated by diode laser «Lasermed 10-03», developed for medical purposes by Russian Engineering Club LLC, Tula, Russian Federation. An experimental biomedical study was performed in vitro on cooled samples of mini-pig liver and muscles and in vivo on the pigmented skin of a live laboratory rat with the assessment of morphometric parameters and dynamics of the regenerative wound process at the irradiated zones.Results. The results of the performed experimental study promoted the development of optimal modes of “blue” (λ = 450 nm) laser irradiation for the precise removal of various pigmented skin formations.Conclusion. Laser light with wavelength 450 nm is a promising technique for the effective treatment of pigmented skin formations, among others CGPN, in pediatric patients as well

Application of near infra-red laser light increases current threshold in optic nerve consistent with increased Na+-dependent transport

Increases in the current threshold occur in optic nerve axons with the application of infra-red laser light, whose mechanism is only partly understood. In isolated rat optic nerve, laser light was applied near the site of electrical stimulation, via a flexible fibre optic. Paired applications of light produced increases in threshold that were reduced on the second application, the response recovering with increasing delays, with a time constant of 24 s. 3-min duration single applications of laser light gave rise to a rapid increase in threshold followed by a fade, whose time-constant was between 40 and 50 s. After-effects were sometimes apparent following the light application, where the resting threshold was reduced. The increase in threshold was partially blocked by 38.6 mM Li+ in combination with 5 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu$$\\end{document}M bumetanide, a manoeuvre increasing refractoriness and consistent with axonal depolarization. Assessing the effect of laser light on the nerve input resistance ruled out a previously suggested fall in myelin resistance as contributing to threshold changes. These data appear consistent with an axonal membrane potential that partly relies on temperature-dependent electroneutral Na+ influx, and where fade in the response to the laser may be caused by a gradually diminishing Na+ pump–induced hyperpolarization, in response to falling intracellular [Na+].

Mismatched Refractive Index Strategy for Fabricating Laser-Driven Wood Diffusers from Bulk Wood for Illumination Applications.

Laser-diode-based solid-state lighting is primarily used in state-of-the-art illumination systems. However, these systems rely on light-converting inorganic phosphors, which have low quantum efficiencies and complex manufacturing conditions. In this study, a mismatched refractive index strategy is proposed to directly convert natural bulk wood into a laser-driven wood diffuser using a simple delignification and polymer infiltration method. The resulting material has the potential to be used in laser-driven diffuse illumination applications. The optical performance of the laser-driven wood diffuser is optimized by changing the density of natural wood. The optimal coefficient of illuminance variation of the wood diffuser is as low as 17.7%, which is significantly lower than that of commercial diffusers. The illuminance uniformity is larger than 0.9, which is significantly higher than the ISO requirements for indoor workplace lighting. The laser damage threshold is 7.9Jcm-2, which is considerably higher than those of the substrates of commercially available phosphors. Furthermore, the optimized wood diffuser exhibits outstanding mechanical properties, excellent thermal stability, tolerance to harsh environmental conditions, and low speckle contrast. These results show that the laser-driven wood diffuser is a promising laser-color converter that is suitable for indoor, long-distance outdoor, undersea, and other high-luminance laser lighting applications.

Ce:LuAG transparent ceramics for high-brightness solid-state lighting: Fabrication and effect of Ce concentration

Compared to phosphor and phosphor in glass, phosphor ceramics have higher thermal properties, and are less prone to thermal quenching. (Ce,Lu)3Al5O12 (Ce:LuAG) has better thermal stability than most of the phosphors, such as (Ce,Y)3Al5O12 (Ce:YAG). However, the high melting point of Lu3Al5O12 (LuAG; up to 2010 °C) presents a great challenge in producing transparent ceramics (TCs), so a series of Ce:LuAG nanopowders with high sintering activity were prepared by the co-precipitation method and then used as initial materials to obtain x at.% Ce:LuAG (x = 0.05, 0.1, 0.2, 0.3, 0.35, 0.4, 0.5, 0.55, 0.6, 0.65, 0.7) TCs by vacuum sintering at 1775 °C for 10 h. Moreover, the luminous properties of typical Ce-doped LuAG phosphors were systematically investigated using excitation by light-emitting diodes or laser diodes (LEDs/LDs). The emission intensity of 0.4 at.% Ce doped sample is the highest among all TCs with Ce amount ranging from 0.05 to 0.7 at.% at room temperature. The photoluminescence intensity of 0.4 at.% Ce:LuAG only decreases by 12.5% from 25 to 225 °C. The 0.4 at.% Ce:LuAG based on 0.8 W LEDs and 1.1 W LDs has the optimum luminous flux of 71.5 and 113.7 lm and the luminous efficiency of 89.3 and 101.4 lm∙W−1, respectively. As Ce concentration increases, a decrease in the luminescence saturation threshold of TCs is observed with a blue laser power density of 2.5–36.9 W∙mm−2. A high-flux yellow-green light of 1166.9 lm is obtained from 0.1 at.% Ce:LuAG when excited with a high-power LD with an energy density of 36.9 W∙mm−2. This work explored the best Ce doping level in Ce:LuAG TCs, as well as the luminescence saturation threshold in remote laser lighting applications.

Robust high-efficiency LuAG: Ce phosphor-in-silica glass (PiSG) for high-brightness laser lighting

Blue laser diodes (LDs), owing to their high electro-optical conversion efficiency, strong directivity, and small size under high power, have paved new paths in the semiconductor lighting and display industry. Blue LDs are expected to replace LED lighting in laser displays, automotive headlights, and other advanced lighting fields. In this study, the Lu3Al5O12: Ce3+ phosphor-in-silica glass (LuAG: Ce-PiSG) is fabricated using spark plasma sintering at 1060 °C. This method enables rapid sintering while maintaining the stability of the silica glass matrix, resulting in high transparency and minimal destruction of the crystal structure of the LuAG: Ce phosphor. The phosphor-converted LDs made from LuAG: Ce-PiSG exhibit high luminous efficacy (298 lm·W−1) and luminous flux (1069 lm). The results show that LuAG: Ce-PiSG has significant potential for application as a robust, high-efficiency phosphor conversion material for high-brightness laser lighting applications.

High efficiency and stable La3Si6N11:Ce phosphor-in-glass film for high power laser lighting

As an inorganic color conversion material, phosphor-in-glass film (PiF) has received extensive attention in the sphere of laser-driven white lighting due to its excellent integrated performance. The yellow-emitting phosphor La3Si6N11:Ce has excellent thermal stability and wide emission band, which makes it more competitive than Y3Al5O12:Ce in laser-driven white lighting. Herein, we embedded La3Si6N11:Ce phosphor powder in a silicate glass matrix (SiO2–B2O3–CaO–Na2O) and sintered it on a sapphire substrate. In the silica-rich glass system, the network structure of silica-oxygen tetrahedral glass is more rigid and the thermal erosion of the phosphor by the silica-based glass is less, which makes the phosphor maintain better performance after low-temperature co-sintering. The quantum efficiency in the optimized LSN phosphor-in-glass film (LSN PiF) is up to 81 %, and the thermal conductivity is 10.2 Wm−1K−1, showing good thermal stability. Impressively, the LSN PiF produces a bright near-white light (0.3323,0.346) at a blue laser of 5.6 W, with corresponding luminous efficiency up to 195 lm/W. Moreover, LSN PiF can maintain about 80 % of the initial luminous intensity after continuous lighting for 24 h at the incident power of 3.5 W. These outstanding properties can advance the development of LSN phosphors in high power laser lighting applications.

Ce3+-based phosphor converter enabling laser lighting to attain both high CRI and high luminous efficacy

Eu2+ doped-CaAlSiN3 possesses broad red emission, enabling a phosphor-converted lighting device to achieve a high color rendering index (CRI) and proper color temperature. However, CaAlSiN3:Eu2+ exhibits relatively slow decay (∼1 μs) and intense re-absorption of luminescence from green/yellow emitters, thereby causing optical saturation and reducing the luminous efficacy. Here, we fabricated a novel phosphor converter comprising Lu3Al5O12:Ce3+ and Y1.3Gd1.6Al5O12:Ce3+ powders. The typical sample, when excited by a blue laser, exhibited a high luminous efficacy of 231 lm/W and a high saturation threshold of 22.2 W/mm2, resulting in a high luminous exitance of 695 lm/mm2. Importantly, the phosphor converter produced a broad emission band that included sufficient cyan and red components, resulting in a full width at half maximum (FWHM) of 134 nm and a high CRI of 81. With this excellent balance between CRI and luminous efficacy, the reported phosphor converter can significantly expand the range of laser lighting applications.

A single institution experience in the treatment of fistula in ano using diode laser (fistula laser closure): short-term outcomes

Introduction Management of the perianal fistula has been always a challenge for colorectal surgeons especially when the external sphincter is involved. Several minimally invasive procedures emerged as an alternative to the traditional surgical approach as fibrin glue injection, ligation of the intershpincteric track (LIFT) and injection of platelet-rich plasma (PRP). Recently, the use of diode laser in proctology has emerged as an alternative to conventional surgical treatment. The laser beam causes shrinkage and sealing of the fistulous track that depends on the power and the duration of laser light application. Patients and methods This study was carried out on 69 patients with perianal fistula in the Gastrointestinal Surgery Unit, General Surgery Department, Tanta University Hospitals, during the study period from February 2021 to December 2022. Patients underwent fistula laser closure (FILAC) using a diode laser, radial fibers, wavelength 1470 nm, and 10 watts of power. Results Sixty nine patients underwent fistula laser closure. The success rate was 74%. There was significance between recurrence and posterior position of the fistulous track of the intersphincteric type. Also, there was significance between recurrence and cases who had a caliber track more than 7 mm but there was no significance between recurrence and length of the track. The procedure was associated with minimal postoperative pain, long period of postoperative discharge, short hospital stay, and early return to normal activities. Conclusion Diode laser is a safe minimally invasive and effective procedure for the treatment of straight non branched short track fistula with some considerations as the caliber track should not exceed 7 mm and the posterior intersphincteric fistula should be treated by lay open fistulotomy. The procedure is also associated with less postoperative pain, early return to normal activities, and minimal recurrence rate but high cost remains a limitation.

Orange-red-emitting (Sr,Ba)3SiO5:Eu2+ phosphor-in-glass film for enhanced color rendering of laser lighting

Nitride red-emitting materials exhibit severe luminance saturation and are thus not suitable for achieving enhanced color rendering in laser lighting applications. The silicate luminescent material (Sr,Ba)3SiO5:Eu2+ displays excellent stability and can emit orange-red light when excited by blue laser light, making it a promising candidate for realizing high-performance laser lighting. In this study, (Sr,Ba)3SiO5:Eu2+ phosphor-in-glass (PiG) films were prepared on a sapphire substrate, and the influences of preparation temperature, mass ratio of phosphor to glass frit (PtG ratio), and film thickness on the application performance of PiG film were analyzed. The (Sr,Ba)3SiO5:Eu2+ PiG film with a PtG ratio of 1:1 and a film thickness of ∼50 μm prepared at 475 °C exhibited optimal comprehensive luminescence performance. This film exhibited a luminous saturation threshold of 5.98 W/mm2, a maximum luminous flux of 372.3 lm, and a luminous efficiency of 62.3 lm/W at the luminous saturation threshold. The maximum luminous flux of the (Sr,Ba)3SiO5:Eu2+ PiG film was 77.6% higher than that of the CaAlSiN3:Eu2+ nitride PiG film. Finally, through the incorporation of green-emitting YAGG:Ce3+ phosphor into the (Sr,Ba)3SiO5:Eu2+ PiG film, laser-driven white light with a luminous flux of 531.7 lm and a high color rendering index (CRI) of 83.4 was realized.

Efekti i procedurave terapeutike në nivelin e triglicerideve te pacientët me diabet tip 2 dhe parodontopati kronike

To monitor blood triglyceride (TRG) values in patients with and without type 2 diabetes mellitus (T2DM) and chron- ic periodontitis (CP) after conservative therapy (scaling and root planning – SRP) with and without laser light ap- plication (low-level laser therapy – LLLT). A total of 120 pa- tients with type 2 diabetes mellitus (T2DM) and diagnosed chronic periodontitis (CP), where the clinical attachment loss (CAL) is ≥4 mm on at least 50% of the affected teeth, were followed. The patients were 35 – 60 years, distribut- ed in three groups A, B and C, 40 in each group. Group A consisted of patients with T2DM and CHP, where conserva- tive periodontal treatment was carried out, supplemented with laser therapy (i.e. T2DM + CP – SRP and LLLT). Group B, where T2DM and CP were diagnosed, consisted of patients treated only with SRP, without application of laser light without laser therapy (i.e. T2DM+ CP – SRP without LLLT). The group C consisted of patients diagnosed with CP, but without T2DM. In all subjects, the values of triglycerides in blood were determined with standard procedure, and then mathematically calculated. The values of TRG in blood in the group A, and the group C after 6 weeks of therapy are significantly lower than the values at the first examination. In the group B the value of TRG in blood after 6 weeks of therapy is in- significantly lower than the value at the first examination. In the group A, the value of TRG in blood after 3 months of therapy and in the group B is insignificantly lower than the value at the first examination in patients. After 3 months of therapy in the group C, the registered value is significantly lower than the value at the first examination. The blood TRG value in the group A 3 months after the therapy is insignificantly higher than the value after 6 weeks of therapy. In the group B and the group C blood TRG value is insignificantly lower than the value at six weeks after therapy. At patients with and without T2DM and CP, regardless of whether they were treated with SRP and LLLT or with SRP, without LLLT, a significant correction of blood TRG was recorded after 6 weeks, and insignificant after 3 months of treatment. SRP and LLLT treat- ment showed the highest effect in the group of patients without T2DM and CP.

Outcomes of diode laser haemorrhoidoplasty in treatment of second, third and fourth grades of haemorrhoids. a retrospective study

Introduction Management of hemorrhoidal disease had been always a challenge for colorectal surgeons. Recently, the use of diode laser in proctology has emerged as an alternative to conventional surgical treatment. The laser beam causes shrinkage and degeneration that depend on the power and the duration of laser light application. It is also associated with minimal postoperative pain, bleeding, discharge and short hospital stay. Patients and methods This prospective study was carried out on 104 patients with second, third and fourth grades of hemorrhoids in the Gastrointestinal Surgery Unit, General Surgery Department, Tanta University Hospitals, during the study period (18 months, from February 2021 to August 2022). All patients underwent laser hemorrhoidoplasty lasotronix device, bare fibers, wavelength 1470 nm and 8 watts of power. Mucopexy was added in 28 patients with grade 4 hemorrhoids. Results Postoperative pain was evaluated using VAS score, in the first 6 h VAS ranged from 4-9 with mean of 5.81±1.23 SD, after 12 h ranged from 1 to 7 with mean of 4.19±1.70 SD. There was significant relation between the grade of hemorrhoid and postoperative edema (P value was less than 0.001) as all of the 24 patients who developed edema, they were grade 4 hemorrhoids. Also, there was relation between grade 4 hemorrhoid and the development of other postoperative complications but P value was not significant (0.066 in infection and 0.260 in recurrence). There was no incontinence or stenosis in all of the 104 patients and recurrence occurred only in 4 cases (3.8%) and underwent conventional hemorrhoidectomy after six months of follow up. Conclusion Diode laser is a safe minimally invasive procedure for the treatment of second, third and fourth grades of hemorrhoids with less postoperative pain and early return to normal activities but high cost remains the only limitation.

Three-dimensional irradiance and temperature distributions resulting from transdermal application of laser light to human knee-A numerical approach.

The use of light for therapeutic applications requires light-absorption by cellular chromophores at the target tissues and the subsequent photobiomodulation (PBM) of cellular biochemical processes. For transdermal deep tissue light therapy (tDTLT) to be clinically effective, a sufficiently large number of photons must reach and be absorbed at the targeted deep tissue sites. Thus, delivering safe and effective tDTLT requires understanding the physics of light propagation in tissue. This study simulates laser light propagation in an anatomically accurate human knee model to assess the light transmittance and light absorption-driven thermal changes for eight commonly used laser therapy wavelengths (600-1200 nm) at multiple skin-applied irradiances (W cm-2 ) with continuous wave (CW) exposures. It shows that of the simulated parameters, 2.38 W cm-2 (30 W, 20 mm beam radius) of 1064 nm light generated the least tissue heating -4°C at skin surface, after 30 s of CW irradiation, and the highest overall transmission-approximately 3%, to the innermost muscle tissue.

Processing of magnesium alloy by energy-intensive multifunction cavitation in a strong magnetic field with laser light excitation and associated sonoluminescence

This work developed a novel metal processing technique referred to as laser-assisted magnetic energy-intensive multifunction cavitation. This technology employs a strong magnetic field to focus bubble energy while applying sonic radiation around a waterjet cavitation jet. Individual bubbles in the cavitation cloud undergo repeated isothermal expansion and adiabatic compression, raising the temperature and pressure of the bubbles. In addition, the presence of a magnetic field over the region between the nozzle exit and the cavitation cloud in which cavitation primarily occurs greatly increases the number and energy density of charged bubble collisions based on the Lorentz force acting between the bubbles. The application of laser light to the charged bubble cloud provides multiphoton excitation that increases the charges of the ions within each bubble, leading to more active collisions. This enhanced cavitation treatment technology was applied to AZ31B magnesium alloy and was found to improve the functionality of the metal.

Study of Laser Light Scattering Methods in Rapid Viability Assessment of Microorganisms under Antibiotics Exposure for Adaptation in Lab-on-A-Chip Format.

The antibiotic resistance (ABR) problem is becoming increasingly disturbing and it is important to implement express methods of ABR testing to allow operative antibiotic therapy decisions. The application of laser light scattering (LLS) in microbiological analysis for express ABR testing of microorganisms has been considered. The ways of miniaturization of laser light scattering for creating the bases of their integration into microbiological laboratory-on-a-chip (MLOC) for clinical express diagnostics have been analysed. The advantage of miniaturization in the context of clinical express analysis realization problems are investigated. A system of parallel measuring cells and illumination, enabling simultaneous testing of a group of antibiotics, was tested by splitting a laser beam with a two-dimensional collimator prepared of nanoporous anodic aluminum oxide. It has been demonstrated that the application of LLS methods, providing high concentration and mass sensitivity as well as a miniaturization potential, is an effective approach in the development of new generation diagnostic instruments. The studies have demonstrated the ability of methods to register effects of antibiotics on microbiological samples within 10 min. The following microorganisms were used in the study: Escherichia coli M-17, Lactobacillus plantarum, Bifidobacterium bifidum, Stenotrophomonas maltophilia.

Vigorous high-efficiency YAGG:Ce phosphor-in-glass film for next-generation laser lighting applications

It is an important challenge to select suitable color converters and apply them to laser diodes (LDs) lighting field. Sapphire plates are used as substrates for phosphor-in-glass films (PiFs) due to their ultrahigh thermal conductivity (∼ 30 W m−1 K−1). Herein, Y3Al3.5Ga1.5O12:Ce3+ (YAGG:Ce) phosphor mixing silicate glass powder is successfully sintered on sapphire plates to fabricate YAGG:Ce phosphor-in-glass film (PiF). The microstructure appearance and photoelectric characteristics of the efficient green color converter are studied in detail. In addition, it is worth noting that the maximum internal quantum efficiency of the prepared PiF is 92%, which is close to that of the original phosphor (98%). Meanwhile, the saturation threshold of YAGG:Ce PiF reaches 38.96 W/mm2 with luminous efficiency (LE) of 230.85 lm/W under the excitation of 460 nm blue LD. Notably, PiF has ultra-high power density while still maintaining such high LE. In order to highlight the application of this color converter in laser lighting, we assemble laser flashlights and fireflies lights. The test of the laser flashlight shows excellent performances such as high brightness, strong focusing effect and wide irradiation range. All indications manifest that YAGG:Ce PiF is an excellent green color converter.

High power multicolor composite fluorescent glass coated with graphene monolayer for laser lighting

Laser lighting technology has become a new star in the field of modern lighting. However, the thermal quenching of optical conversion materials occurs at high incident power density, so it is an urgent problem to improve their heat resistance. In this paper, a kind of Lu3Al5O12:Ce&CaAlSiN3:Eu2+ (LuAG&CASN) composite phosphor-in-glass (PiG) suitable for high power laser diode is prepared, which shows high brightness and high display. In addition, the graphene monolayer grown by chemical vapor deposition (CVD) is coated on the surface of LuAG&CASN-PiG to further improve the luminescence performance of PiG. The saturation power threshold of the graphene-PiG (G-PiG) sample can reach 4.5 W and the maximum output lumen flux can reach 317.95 lm when the system is excited with 450 nm blue light using the reflective structure. Compared with the samples without graphene coating, the luminescence efficiency of G-PiG was improved by 23.2%. This single-layer graphene surface coating method provides a new idea for the preparation of high-performance fluorescence conversion materials for laser lighting applications, which may play an important role in the future laser lighting.

Porous Ce:YAG ceramics with controllable microstructure for high‐brightness laser lighting

AbstractIn order to meet the increasing demand for high‐power laser diode lighting and displays, phosphor converters with high‐brightness and high‐directionality ought to be constructed to enhance the luminance and luminous efficacy. However, the pores formed during the sintering of phosphor ceramics affect the scattering effect and directionality of light. Therefore, porosity optimization and pore size regulation need to be explored. In this work, a series of Ce:YAG ceramics with various porosities and pore sizes were prepared. The influences of porosity and pore size on the microstructure, light confinement ability, and optical properties of Ce:YAG ceramics were studied. The ceramic phosphor with a porosity of 10 vol.% and a pore size of 3 μm exhibits a good spot confinement ability and shows a high luminous flux value of 3430 lm and a central luminance (1669 592 cd/m2) under blue laser excitation. The 10 vol.% Ce:YAG ceramic phosphor with a pore size of 5 μm has the highest emission intensity and gives a maximum luminous efficacy of 268 lm/W and a luminous flux of 4020 lm under 30 W/mm2 blue laser excitation. Thus, the porous Ce:YAG ceramics are expected to be a promising candidate for high‐brightness laser lighting and projection applications.

All-inorganic color converter based on a phosphor in bismuthate glass for white laser diode lighting.

Blue laser diodes (LDs) combined with phosphors have been recognized as the next-generation solid white lighting technology. The phosphor-in-glass (PiG) coating is used for packaging as an appropriate fluorescent conversion material applied to white light LDs. In this work, a low melting point glass Bi2O3-B2O3-ZnO-BaO (BiBZBa), which was mixed with YAG:Ce3+ phosphor powder, was selected as a glass matrix, and the coating of the phosphor in bismuthate glass (PiBG) was successfully fabricated on different substrates through multilayer screen-printing and low-temperature sintering processes. The PiBG-coated substrates were integrated with a 440 nm LD chip in different interlayer structures to obtain PiBG-packaged white laser diodes (WLDs). The thermal performance of Bi2O3-B2O3-ZnO-BaO glass and the phase composition, microstructure, and luminescence properties of PiBG coatings were studied, and the optical performances of WLDs were investigated. When the reflective WLDs were excited by a blue laser with a laser power density of up to 9.3 W mm-2, the related luminous flux (LF), luminous efficiency (LE), and chromaticity coordinates were 3091 lm, 103 lm W-1, and (0.32, 0.32), respectively, indicating great potential in PiBG-packaged high power laser lighting applications.