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Blocking the near-infrared region (NIR) is indispensable for saving energy consumed to maintain the interior temperature in buildings. However, simultaneously enhancing transmission in visible light and blocking in the NIR remains challenging. Here, we theoretically demonstrate a transparent all-dielectric metasurface selectively blocking the NIR by using TiO 2 nanocylinders and an indium tin oxide (ITO) layer. The ITO layer is implemented as a back reflector because ITO is transparent in visible light, whereas the ITO becomes a reflective material in the long-wavelength region (λ > 1500 nm). The designed metasurface exhibits high average transmittance of 70% in visible light and high solar energy rejection (SER) of 90% in the NIR. Furthermore, the blocking capability in the NIR of the designed metasurface is maintained over a wide range of an incident angle and polarization angle of light. Therefore, the metasurface gives a guideline for designing energy-saving applications.

The after-pulsing effect is a common problem in high-speed and low-noise single-photon detection based on single-photon avalanche diodes (SPADs). This article presents a dual anode InGaAs/InP SPAD (DA-SPAD) with two separate anode output ports that can be utilized for discriminating relatively weak avalanche signals, providing a simple and robust configuration of the SPAD-based single-photon detection system. Weak avalanche signals with amplitudes below the amplitude of the parasitic capacitive response of the SPAD were easily detected by the DA-SPAD and a simple subtraction circuit. The gated Geiger-mode performance of the DA-SPAD was also investigated. At a gating frequency of 1 GHz, the detection efficiency was 20.4% with an after-pulse probability of 3.5% at a temperature of -20 °C.

Lightwave propagation through a multilayer structure of patterned semi-transparent curved surfaces is a fundamental issue for various display applications from practical industrial problems such as moiré pattern strain in touch panel displays to fundamental research issues in layered tensor displays and layered complex modulation holographic displays. In this paper, a wave optic modeling of multiple layers of patterned semi-transparent curved surfaces is presented. The proposed wave optic modeling is based on the algorithmic framework used in the field of polygon computer-generated holograms, a framework which can additionally devise the characteristic transmittance function of textured curved surfaces. To present an industrial application, the proposed modeling method is used to numerically simulate the visual perception of the moiré patterns observed in the layered structures of transparent phase-only patterned curved surfaces and their diverse variations with a change in observation angle.

In this paper, we investigate the relationship between depth perception and several disparity parameters in stereoscopic images. A number of subjective experiments were conducted using various 3D displays, which indicate that depth perception of stereoscopic images is proportional to depth difference and is inversely related to the camera distance. Based on this observation, we developed some formulas to quantify the degree of depth perception of stereoscopic images. The proposed method uses depth differences and the camera distance between the objects and the 3D camera. This method also produces improved depth perception estimation by using non-linear functions whose inputs include a depth difference and a camera distance. The results show that the proposed method provides noticeable improvements in terms of correlation and produces more accurate depth perception estimations of stereoscopic images.

Fourier modal method based quantitative analysis method of optical power flow and energy loss in general multi-block photonic structures with an internal dipole emitter is described. The analytic expressions of modal power flow and loss are derived for accurate and efficient quantitative analysis. It is revealed that a few dominating excited photonic modes substantially govern the internal energy flow and energy loss. The optical characteristics of the dominant modes are investigated.

We investigate the thermal characteristics of a polymer-clad fiber laser under natural convection when it is strongly pumped up to the damage point of the fiber. For this, we utilize a temperature sensing technique based on a fiber Bragg grating sensor array. We have measured the longitudinal temperature distribution of a 2.4-m length ytterbium-sensitized erbium-doped fiber laser that was end-pumped at approximately 975 nm. The measured temperature distribution decreases exponentially, approximately, decaying away from the pump-launch end. We attribute this to the heat dissipation of absorbed pump power. The maximum temperature difference between the fiber ends was approximately 190 K at the maximum pump power of 60.8 W. From this, we estimate that the core temperature reached approximately 236 degrees C.