Microtextured polydimethylsiloxane sheets exhibit an exceptionally low reflectance of ≲0.0005 across the entire thermal infrared wavelengths while maintaining high resilience.

This roadmap article focuses on spatially incoherent digital holography (IDH). Representative IDH methods such as optical scanning holography (OSH), Fresnel incoherent correlation holography (FINCH), coded aperture correlation holography (COACH), IDH with a Fresnel zone aperture, and IDH with an interferometer along with a state-of-the-art optical device are introduced as modern IDH methods. We describe these IDH techniques with applications of three-dimensional (3D) imagers, 3D thermography, and 3D microscopy.

We propose a single-exposure phase-shifting digital holography based on a wave-splitting method using a random-phase reference wave. A random-phase reference wave gives random-phase distribution on the digital hologram. Using the amplitude and the phase distributions of the reference wave, the fully complex amplitude of the object wave is obtained. The proposed method requires not devised optical systems but ordinary imaging devices, such as CCD cameras. A preliminary experimental result is given to confirm the proposed method.

The furnace effect is a major uncertainty source in the realization of high-temperature fixed points in metal–carbon systems. The cause of this effect is as yet unexplained, and understanding it is a high-priority task for the inclusion of fixed points in future high-temperature metrology. In this paper, the furnace effect is studied experimentally and systematically with three furnaces, two cells, and two radiation thermometers. The copper point is chosen for the fixed point of investigation in order to eliminate the influence of the properties of the furnace. Correction for drift and the size-of-source effect of the thermometer is applied to achieve the required measurement accuracy. As a result, the furnace effect has been demonstrated quantitatively for the first time as the difference in radiance temperature of the same cell observed in different furnaces by the same thermometer. The experimental results show that it is related to the dimension of the furnace and the design of the fixed-point blackbody cell.

The improved single-exposure phase-shifting digital holography using a random-phase reference wave is proposed. The algorithm for obtaining a complex amplitude of an object wave is improved. In the proposed algorithm, the reference wave is treated as not a random-phase but a random-complex amplitude. Therefore, the algorithm uses proper amplitude information of the reference wave. Both numerical simulations and experimental results are given to confirm the effectiveness of the proposed algorithm.