Photonics, Vol. 11, Pages 381: Optical Design of a Wavelength Selective Switch Utilizing a Waveguide Frontend with Beamsteering Capability Photonics doi: 10.3390/photonics11040381 Authors: Georgios Patsamanis Dimitra Ketzaki Dimitrios Chatzitheocharis Konstantinos Vyrsokinos Wavelength selective switches (WSSs) are essential elements for wavelength division multiplexing (WDM) optical networks, as they offer cost-effective, high port-count and flexible spectral channel switching. This work proposes a new hybrid WSS architecture that leverages the beam shaping and steering features of uniform si ..read more

Photonics, Vol. 11, Pages 382: Synthesis of Aluminium Nitride-Based Coatings on Mild Steel Substrates Utilising an Integrated Laser/Sol–Gel Method Photonics doi: 10.3390/photonics11040382 Authors: Ogulcan Eren Alhaji M. Kamara Huseyin Kursad Sezer Sundar Marimuthu The field of protective coatings for industrial applications is continuously evolving, driven by a need for materials that offer exceptional hardness, enhanced wear resistance, and low friction coefficients. Conventional methods of coating development, such as physical vapour deposition (PVD) and chemical vapour deposition ..read more

Photonics, Vol. 11, Pages 384: Coherent Raman Scattering Spectral Shapes in a Strong Excitation Regime (Model Calculations) Photonics doi: 10.3390/photonics11040384 Authors: Georgi B. Hadjichristov The influence of the interference between coherent processes in third-order nonlinear Raman scattering on the spectral shapes of Raman-scattered light waves is numerically modeled and discussed in the cases of commonly used coherent Raman spectroscopy techniques. The effects on the lineshapes depending on the laser intensity are analyzed for the coherent Raman spectroscopy performed via the excitati ..read more

Photonics, Vol. 11, Pages 376: Time-Division Multiplexed Optical Covert Communication System Based on Gain-Switched Optical Pulses Photonics doi: 10.3390/photonics11040376 Authors: Dong Liu Yongliang Yin Mingyu Cui Zhanqi Liu Huatao Zhu In optical covert communication systems based on gain-switched distributed feedback semiconductor lasers, the trade-off between the modulation frequency and the spectral imperceptibility limits the bit rate of the secure channel. To improve the system performance in terms of the bit rate and covertness, optical time-division multiplexing is introduced to optica ..read more

Photonics, Vol. 11, Pages 377: Agreement on Anterior Chamber Depth Measurement between Three Commercially Available Devices Photonics doi: 10.3390/photonics11040377 Authors: Veronica Noya-Padin Hugo Pena-Verdeal Jacobo Garcia-Queiruga Irene Sampedro-Mariño Maria Jesus Giraldez Eva Yebra-Pimentel The present study aimed to assess the agreement of three commercially available devices on the measurement of anterior chamber depth (ACD) with and without compensation by central corneal thickness measurement (CCT). Fifty eyes were included in an observational cross-sectional study. Participants under ..read more

Photonics, Vol. 11, Pages 378: Impact of Motion Characteristics of Airborne Platforms on the Performance of Space Laser Communication Links Photonics doi: 10.3390/photonics11040378 Authors: Xin Zhang Shiming Gao Zhi Liu Qingfang Jiang Lixin Meng Helong Wang Keyan Dong When a platform carrying a space laser communication system moves through the atmosphere, the relative motion of the turret and the air produces fluctuations in the air density, which affects the beam propagation, and, hence, the laser communication performance. In this paper, we propose a performance analysis method for the spac ..read more

Photonics, Vol. 11, Pages 379: Revisiting Poincaré Sphere and Pauli Algebra in Polarization Optics Photonics doi: 10.3390/photonics11040379 Authors: Tiberiu Tudor Gabriel Voitcu We present one of the main lines of development of Poincaré sphere representation in polarization optics, by using largely some of our contributions in the field. We refer to the action of deterministic devices, specifically the diattenuators, on the partial polarized light. On one hand, we emphasize the intimate connection between the Pauli algebraic analysis and the Poincaré b ..read more

Photonics, Vol. 11, Pages 380: Sensitive Detection of Silicon in Aqua Phase by Microwave-Assisted Laser-Induced Breakdown Spectroscopy Photonics doi: 10.3390/photonics11040380 Authors: Ali M. Alamri Zeyad T. Alwahabi Microwave-assisted laser-induced breakdown spectroscopy (MA-LIBS) was demonstrated to be an effective method for the quantitative detection of silicon in the aqua phase. Microwave radiation was transmitted into plasma using a near-field applicator device under ambient pressure and temperature conditions. Silicon detection was performed directly on the surface of a water jet. Two S ..read more

Photonics, Vol. 11, Pages 375: Damascene Process Development for Low-Loss Photonics Devices with Applications in Frequency Comb Photonics doi: 10.3390/photonics11040375 Authors: Qiaoling Zhou Yejia Jin Shaonan Zheng Xingyan Zhao Yang Qiu Lianxi Jia Yuan Dong Qize Zhong Ting Hu Silicon nitride (SiN) is emerging as a material of choice for photonic integrated circuits (PICs) due to its ultralow optical losses, absence of two-photon absorption in telecommunication bands, strong Kerr nonlinearity and high-power handling capability. These properties make SiN particularly well-suited for application ..read more

Photonics, Vol. 11, Pages 371: Effects of Squeezing on the Power Broadening and Shifts of Micromaser Lineshapes Photonics doi: 10.3390/photonics11040371 Authors: Leonardi Hernández-Sánchez Irán Ramos-Prieto Francisco Soto-Eguibar Héctor Manuel Moya-Cessa AC Stark shifts have an impact on the dynamics of atoms interacting with a near-resonant quantized single-mode cavity field, which is relevant to a single atom micromaser. In this study, we demonstrate that, when the field is in a squeezed coherent state, atomic lineshapes are highly sensitive to the squeezing parameter. Furthermore, we show t ..read more