In this Letter, a bidirectional amplifier configuration suppressing the relative intensity noise in a 1950-nm linearly polarized single-frequency fiber laser (SFFL) is proposed. The scheme to amplify the signal in a nonlinear saturated amplification regime with low gain distribution for suppressing the RIN is theoretically analyzed. By optimizing the input power level and reflectivity of the bidirectional power-amplifier, the RIN is decreased maximally by >24dB within the frequency range of 200 kHz. A stable output power of over 5.16 W with a polarization extinction ratio of 21.2 dB is obtained. Additionally, the amplified signal maintains a linewidth of 7.1 kHz nearly identical with that of the seed, both with a signal-to-noise ratio of more than 60 dB. This all-optical technique on noise suppression applied to the fiber amplifier paves the way to realize low-noise SFFL with power improvement.A novel, to the best of our knowledge, approach to the design of the single-photon sources emitting in the spectral regions of 1060 and 1337 nm was developed. A unique hybrid structure based on colloidal CdSe/CdS/ZnS nanocrystals and neodymium(III) 1,3-diketonate was created. Direct energy transfer from the CdSe/CdS/ZnS single nanocrystal to the near-infrared (NIR) luminescent Nd(III) complex was observed and investigated by spectroscopic methods. The single-photon emission mode was confirmed for the novel hybrid source by Hanbury Brown and Twiss experiments.Optical technologies have been widely studied to satisfy the interconnect demand in high-performance computers and data centers, and free-space optical interconnects have been investigated for flexible card-to-card applications. To increase the interconnect speed and range, in this Letter we propose a reconfigurable free-space optical interconnect with 16-carrierless-amplitude-phase (16-CAP) symbol modulation and filter-enhanced spatial modulation (FE-SM). The 16-CAP increases the interconnect speed in the symbol domain, and the FE-SM scheme increases the speed in the spatial domain, even under highly correlated optical interconnect channels. A 50 Gb/s reconfigurable optical interconnect is experimentally demonstrated. The results show that the impact of FE-SM on the bit error rate (BER) is negligible, while the speed is significantly improved. Compared with the conventional SM scheme, the BER is improved by over one order of magnitude. The proposed scheme is also capable of extending the interconnect range.  https://www.selleckchem.com/products/camostat-mesilate-foy-305.html  The results show that over 70% range extension and 50% speed increase can be achieved simultaneously. The proposed scheme with a 16-CAP and FE-SM provides a promising solution in free-space optical interconnects.Inducing and controlling temperature gradients in illuminated subwavelength plasmonic structures is a challenging task. Here, we present a strategy to remotely induce and tune temperature gradients in a subwavelength metallic nanocone by adjusting the angle of incidence of linearly polarized continuous-wave illumination. We demonstrate, through rigorous three-dimensional numerical simulations, that properly tilting the incident illumination angle can increase or decrease the photoinduced temperature gradients within the nanostructure. We analyze the apex-base photoinduced temperature gradient for different illumination directions, resembling typical illumination schemes utilized in surface or tip-enhanced Raman spectroscopy.A flexible broadband absorber based on an all-dielectric multilayer structure is proposed to get an average absorbance of 97.4%, covering the whole visible light. Additionally, such high absorption presents an extraordinary angular tolerance of up to ±50∘. Due to the single broadband resonance in the highly lossy Fabry-Perot (F-P) cavity and the intrinsic loss property of Ge, the proposed multilayer structure achieves the broadband absorption effect. Furthermore, the simple all-dielectric multilayer configuration requires no noble metal, making the lithography-free, large-scale, cost-effective manufacturing process feasible. Meanwhile, the good substrate adaptation facilitates its preparation on a flexible substrate. Accordingly, a three-dimensional object covered by the proposed flexible absorber can be treated as a two-dimensional black hole, revealing the effect of stealth. The proposed perfect absorber shows potentials for camouflage coating, solar energy collection, flexible optoelectronics, and other fields.We show that waveguide sensors can enable a quantitative characterization of coronavirus spike glycoprotein-host-receptor binding-the process whereby coronaviruses enter human cells, causing disease. We demonstrate that such sensors can help quantify and eventually understand kinetic and thermodynamic properties of viruses that control their affinity to targeted cells, which is known to significantly vary in the course of virus evolution, e.g., from SARS-CoV to SARS-CoV-2, making the development of virus-specific drugs and vaccine difficult. With the binding rate constants and thermodynamic parameters as suggested by the latest SARS-CoV-2 research, optical sensors of SARS-CoV-2 spike protein-receptor binding may be within sight.A new technique for the fast implementation of Brillouin optical time-domain reflectometry has been proposed and demonstrated with the optical chirp chain (OCC) reference wave. By using the fixed bandpass filter and envelope detection, the spontaneous Brillouin spectrum can be online demodulated in the time domain for truly distributed, one-end access and fast measurement. The measurement time is only limited by the pulse repetition rate and averaging times. For a 400 m single-mode fiber, a 31.58Hz strain vibration on a 2 m fiber segment is measured for a wide dynamic range (∼3200µε) with an equivalent sampling rate of 200Hz when 200 times of averaging is performed. Furthermore, the performance on the measurement accuracy is investigated with different OCC frequency spans and durations.The aliasing effect in the discrete Fourier transform inherent will impose a serious detrimental effect on conventional phase retrieval measurement accuracy with under-sampled intensity. In this Letter, we describe a modal-based nonlinear optimization phase retrieval approach that is capable of retrieving wavefront measurements using under-sampled intensities. The extended Nijboer-Zernike theory is introduced to establish an analytic solution between wavefront phase and intensity image, and then nonlinear optimization is further utilized to solve wavefront aberration coefficients from under-sampled intensity data. The feasibility and accuracy of the algorithm are verified by simulations and experiments. This is a promising method that is especially suitable for full field phase recovery of optical systems with a relatively high numerical aperture.