Integrative Lighting Aimed at Patients with Psychiatric and Neurological Disorders.

The purpose of this paper is to investigate the impact of circadian lighting-induced melatonin suppression on patients with psychiatric and neurological disorders in hospital wards by using an ad-hoc metrology framework and the subsequent metrics formalized by the CIE in 2018. A measurement scheme was conducted in hospital ward rooms in the Department of Neurology, Zealand University Hospital, at Roskilde in Denmark, to evaluate the photometric and colorimetric characteristics of the lighting system, as well as its influence on the circadian rhythm of the occupants. The measurement scheme included point measurements and data logging, using a spectrophotometer mounted on a tripod with adjustable height to assess the newly installed circadian lighting system.

Rare Earth Orthoferrite Tuning of Transmitted Waves as Natural Metamaterials.

Metamaterials display many electromagnetic properties, such as the manipulation of electromagnetic waves through the arrangement of small discrete structures. However, complex designs of mechanically or electrically patterned structures are required to modify these properties. We report on the use of rare earth orthoferrites to tune transmitted waves by engineering the thickness, composition, and temperature using terahertz (THz) time-domain spectroscopy.

Mode jumping of split-ring resonator metamaterials controlled by high-permittivity BST and incident electric fields.

We investigate the resonant modes of split-ring resonator (SRR) metamaterials that contain high-permittivity BST block numerically and experimentally. We observe interesting mode-jumping phenomena from the BST-included SRR absorber structure as the excitation wave is incident perpendicularly to the SRR plane. Specifically, when the electric field is parallel to the SRR gap, the BST block in the gap will induce a mode jumping from the LC resonance to plasmonic resonance (horizontal electric-dipole mode), because the displacement current excited by the Mie resonance in the dielectric block acts as a current channel in the gap.

Terahertz time domain spectroscopic investigation of spin reorientation transitions in HoFeO₃.

Both continuous and discontinuous spin reorientation transitions in the HoFeO₃ orthoferrite have been further investigated in this paper. Here, we use terahertz spectroscopy through the terahertz ferromagnetic and antiferromagnetic resonances to study the thermodynamics of the spin reorientation transitions in HoFeO₃ ceramics. The spin reorientations are driven by changes in the anisotropy energy, and the spin moments in and out of the (a, c) plane correspond to the continuous transitions and discontinuous transitions.

Ultralow temperature terahertz magnetic thermodynamics of perovskite-like SmFeO3 ceramic.

The terahertz magnetic properties of perovskite-like SmFeO3 ceramic are investigated over a broad temperature range, especially at ultralow temperatures, using terahertz time-domain spectroscopy. It is shown that both resonant frequencies of quasi-ferromagnetic and quasi-antiferromagnetic modes have blue shifts with the decreasing temperature due to the enhancement of effective magnetic field. The temperature-dependent magnetic anisotropy constants are further estimated using the resonant frequencies, under the approximation of omitting the contribution of Sm(3+) magnetic moments to the effective field.