To derive the impact of chip size reduction on optical efficiency in micro-LED array panels, blue InGaN/GaN LEDs, which consist of 21×7 arrays (60 ppi display) with different mesa sizes on sapphire substrates, are designed and fabricated in this study. Changing the mesa area of the chip is first proposed to investigate the luminous efficiency (cd/A) of the screen. The current efficiency with a peak wavelength of 450 nm reaches up to 14.29 cd/A for the biggest pixel 50µm×60µm and to 12.25 cd/A for the 15µm×25µm chip, delivering high-level efficiencies to the current LED research field. The mechanisms of size-dependent efficiency variation trends and efficiency droops of blue LEDs are investigated experimentally, confirming that the current efficiency is more efficient at high injection current density while exhibiting poorer performance at the low current density region for smaller chips. The peak efficiency corresponds to higher current density with a decrease in chip size according to the carrier recombination ABC model. Moreover, the characteristic curve of the spectrum and the changes in the yellow light band under different incident light conditions (i.e., 355 nm and 375 nm) are analyzed by photoluminescence.We propose a photonic crystal fiber (PCF) sensor based on graphene oxide (GO) composite film modification to simultaneously measure the multi-parameter sensing characteristics of humidity, temperature, and glucose concentration. The GO-polyvinyl alcohol (PVA) composite film is used to measure the humidity-sensing characteristics of the sensor, and the glucose oxidase composite film is used to measure the sensing characteristics of the glucose concentration, respectively. Experiment results show that the sensitivities of the temperature of the GO-PVA coating structure are 0.037 nm/°C, 0.047 nm/°C, and 0.031 nm/°C; the sensitivities of humidity are 0.059 nm/%RH, 0.121 nm/%RH, and 0.047 nm/%RH; and the sensitivities of the glucose concentration of the GO-GOD coating structure are 0.028 nm/(g/L), 0.049 nm/(g/L), and 0.010 nm/(g/L) for three interference dips, respectively. The structure is simple to manufacture and can be used as a sensor for detecting multiple parameters. It can be widely used in biomedicine, environmental monitoring, and other fields.Different types of photonic crystal components have been modeled by approximate RLC circuits. The proposed lumped circuits exploit the analogy of photonic crystal elements and RLC circuits. They are either coupled to each other or inserted like lumped circuits to imitate wave propagation within the photonic devices. Different examples such as side-coupled waveguide-cavity systems, side-coupled cavity-cavity systems, and improved structures are investigated for evaluating the theory. It is shown that the proposed circuits are exact enough to be substituted into the complicated calculations of numerical methods. In addition, the presented practical and straightforward procedure can be employed for flexible and efficient design. The results are verified using the finite-difference time-domain numerical simulations and coupled-mode theory for various devices.In recent years, mobile phones with glass curved screens have become more and more widely used. The irregular shape of the curved screen and the light transmittance characteristic of the glass have brought great challenges to its automatic defect detection. Aiming at the defect detection of the glass cover of the curved screen, this paper designs a full-scale scanning system by combining motion and three-dimensional (3D) features. First, a scanning system is constructed, and a geometric error modeling method is proposed to improve the accuracy of the scanning system; second, based on the point cloud of the 3D glass cover obtained by the scanning system, a point cloud registration method is presented by integrating the motion and 3D features; finally, the laser tracker is further used to calibrate the scanning system to analyze the mechanical error. Experimental results show that the introduction of straightness error and perpendicularity error can effectively solve the mismatch and fault problems of point cloud registration, and improve the accuracy of the scanning system. In addition, the registration method proposed in this paper can effectively reconstruct the complete point cloud of 3D glass cover for detection. https://www.selleckchem.com/products/azd3514.html The reconstruction accuracy of the plane part can reach 0.031 mm, and that of the curved part can reach 0.091 mm.The paper discusses photoinduced microrelief formation in a film of an azopolymer. A theoretical study of the effect of laser beam polarization on the balance of optical forces acting under the direct action of paraxial Gaussian beams on the irradiated substance was made. We show that taking into account the gradient and scattering components of the force does not allow us to correctly describe the shape of the microasperities obtained on a carbazole-containing azopolymer. An approximation function is presented that describes the dependence of the microasperities' shapes on the non-gradient component of the optical force of laser radiation in the absence and presence of a vortex phase. A comparative analysis of the approximation results and experimentally obtained microreliefs was carried out.Using a Monte Carlo algorithm to simulate the scattering of sunlight in an atmosphere-ocean system, the degree of circular polarization of light in the ocean has been calculated at multiple depths and directions. In this system circularly polarized light is produced by the reflection of light from beneath the surface at an incident angle greater than the critical angle. We present the results of these simulations for different solar angles, wavelengths of light, and models that include the presence of aerosols in the atmosphere and hydrosols in the water.We report the demonstration of imaging of a single human hair with a terahertz quantum cascade laser (THz-QCL) source based on intracavity difference-frequency generation. A single human hair whose diameter was about 100 µm was detected using the THz-QCL source operating at 240 K, of which the THz beam had a linear polarization. The results show that the THz image of a human hair clearly depends on the polarization direction of the THz beam. The THz QCL sources that are capable of room temperature operation will be useful for detection of small foreign objects like human hairs.
To derive the impact of chip size reduction on optical efficiency in micro-LED array panels, blue InGaN/GaN LEDs, which consist of 21×7 arrays (60 ppi display) with different mesa sizes on sapphire substrates, are designed and fabricated in this study. Changing the mesa area of the chip is first proposed to investigate the luminous efficiency (cd/A) of the screen. The current efficiency with a peak wavelength of 450 nm reaches up to 14.29 cd/A for the biggest pixel 50µm×60µm and to 12.25 cd/A for the 15µm×25µm chip, delivering high-level efficiencies to the current LED research field. The mechanisms of size-dependent efficiency variation trends and efficiency droops of blue LEDs are investigated experimentally, confirming that the current efficiency is more efficient at high injection current density while exhibiting poorer performance at the low current density region for smaller chips. The peak efficiency corresponds to higher current density with a decrease in chip size according to the carrier recombination ABC model. Moreover, the characteristic curve of the spectrum and the changes in the yellow light band under different incident light conditions (i.e., 355 nm and 375 nm) are analyzed by photoluminescence.We propose a photonic crystal fiber (PCF) sensor based on graphene oxide (GO) composite film modification to simultaneously measure the multi-parameter sensing characteristics of humidity, temperature, and glucose concentration. The GO-polyvinyl alcohol (PVA) composite film is used to measure the humidity-sensing characteristics of the sensor, and the glucose oxidase composite film is used to measure the sensing characteristics of the glucose concentration, respectively. Experiment results show that the sensitivities of the temperature of the GO-PVA coating structure are 0.037 nm/°C, 0.047 nm/°C, and 0.031 nm/°C; the sensitivities of humidity are 0.059 nm/%RH, 0.121 nm/%RH, and 0.047 nm/%RH; and the sensitivities of the glucose concentration of the GO-GOD coating structure are 0.028 nm/(g/L), 0.049 nm/(g/L), and 0.010 nm/(g/L) for three interference dips, respectively. The structure is simple to manufacture and can be used as a sensor for detecting multiple parameters. It can be widely used in biomedicine, environmental monitoring, and other fields.Different types of photonic crystal components have been modeled by approximate RLC circuits. The proposed lumped circuits exploit the analogy of photonic crystal elements and RLC circuits. They are either coupled to each other or inserted like lumped circuits to imitate wave propagation within the photonic devices. Different examples such as side-coupled waveguide-cavity systems, side-coupled cavity-cavity systems, and improved structures are investigated for evaluating the theory. It is shown that the proposed circuits are exact enough to be substituted into the complicated calculations of numerical methods. In addition, the presented practical and straightforward procedure can be employed for flexible and efficient design. The results are verified using the finite-difference time-domain numerical simulations and coupled-mode theory for various devices.In recent years, mobile phones with glass curved screens have become more and more widely used. The irregular shape of the curved screen and the light transmittance characteristic of the glass have brought great challenges to its automatic defect detection. Aiming at the defect detection of the glass cover of the curved screen, this paper designs a full-scale scanning system by combining motion and three-dimensional (3D) features. First, a scanning system is constructed, and a geometric error modeling method is proposed to improve the accuracy of the scanning system; second, based on the point cloud of the 3D glass cover obtained by the scanning system, a point cloud registration method is presented by integrating the motion and 3D features; finally, the laser tracker is further used to calibrate the scanning system to analyze the mechanical error. Experimental results show that the introduction of straightness error and perpendicularity error can effectively solve the mismatch and fault problems of point cloud registration, and improve the accuracy of the scanning system. In addition, the registration method proposed in this paper can effectively reconstruct the complete point cloud of 3D glass cover for detection. https://www.selleckchem.com/products/azd3514.html The reconstruction accuracy of the plane part can reach 0.031 mm, and that of the curved part can reach 0.091 mm.The paper discusses photoinduced microrelief formation in a film of an azopolymer. A theoretical study of the effect of laser beam polarization on the balance of optical forces acting under the direct action of paraxial Gaussian beams on the irradiated substance was made. We show that taking into account the gradient and scattering components of the force does not allow us to correctly describe the shape of the microasperities obtained on a carbazole-containing azopolymer. An approximation function is presented that describes the dependence of the microasperities' shapes on the non-gradient component of the optical force of laser radiation in the absence and presence of a vortex phase. A comparative analysis of the approximation results and experimentally obtained microreliefs was carried out.Using a Monte Carlo algorithm to simulate the scattering of sunlight in an atmosphere-ocean system, the degree of circular polarization of light in the ocean has been calculated at multiple depths and directions. In this system circularly polarized light is produced by the reflection of light from beneath the surface at an incident angle greater than the critical angle. We present the results of these simulations for different solar angles, wavelengths of light, and models that include the presence of aerosols in the atmosphere and hydrosols in the water.We report the demonstration of imaging of a single human hair with a terahertz quantum cascade laser (THz-QCL) source based on intracavity difference-frequency generation. A single human hair whose diameter was about 100 µm was detected using the THz-QCL source operating at 240 K, of which the THz beam had a linear polarization. The results show that the THz image of a human hair clearly depends on the polarization direction of the THz beam. The THz QCL sources that are capable of room temperature operation will be useful for detection of small foreign objects like human hairs.
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