This paper reviews the recent biomedical detection developments of scanning near-field optical microscopy (SNOM), focusing on scattering-type SNOM (s-SNOM), atomic force microscope-based infrare

This paper reviews the recent biomedical detection developments of scanning near-field optical microscopy (SNOM), focusing on scattering-type SNOM (s-SNOM), atomic force microscope-based infrared spectroscopy (AFM-IR), peak force infrared microscopy (PFIR), and photo-induced force microscopy (PiFM), which have the advantages of label-free, non-invasive and specific spectral recognition. Considering the high-water content of biological samples and the strong absorption of water by infrared waves, we divide the relevant researches of these techniques into two categories, one based on non-liquid environment and the other based on liquid environment. In the non-liquid environment, the chemical composition and structure information of biomedical samples can be obtained with nanometer resolution. In the liquid environment, these techniques can be used to monitor the dynamic chemical reaction process and track the process of chemical composition and structure change of single molecules, which are conducive to exploring the development mechanism of physiological processes. We elaborate their experimental challenges, technical means and actual cases for three micro biomedical samples (including biomacromolecules, cells and tissues). Their development prospect and the challenges are also discussed. This work lays a foundation for the rational design and efficient use of near-field optical microscopy to explore the characteristics of microscopic biology.show less

The optical angular momentum is ubiquitous to the science of light, especially whenever the polarization state and the spatial distribution of the phase are involved, which are most often associ

The optical angular momentum is ubiquitous to the science of light, especially whenever the polarization state and the spatial distribution of the phase are involved, which are most often associated with the spin and orbital parts of the total angular momentum, respectively. Noteworthy, these two contributions to the total optical angular momentum have been originally introduced in the framework of a mechanical detection framework involving a torsion pendulum. Today, the classical and quantum mechanical aspects of spin and orbital angular momentum of light, and their mutual coupling, remain active research topics offering exciting perspectives for photonic technologies. This brief historical overview shows how the torsion pendulum has accompanied scientific progress on mechanical effects based on the angular degrees of freedom of light since Beth's pioneering contribution published in 1935 [Phys. Rev. {\bf 48}, 471 (1935)].show less

This study analyzes the linewidth narrowing characteristics of free-space-running BLs and investigates the approaches to achieve linewidth compression and power enhancement simultaneously. The r

This study analyzes the linewidth narrowing characteristics of free-space-running BLs and investigates the approaches to achieve linewidth compression and power enhancement simultaneously. The results show that the Stokes linewidth behavior in a free-space-running BL cavity is determined by the phase diffusion of the pump and the technical noise of the system. Experimentally, a Stokes light output with a power of 22.5 W and a linewidth of 3.2 kHz was obtained at a coupling mirror reflectivity of 96%, which is nearly 2.5 times compressed compared to the linewidth of the pump (7.36 kHz). In addition, the theorical analysis shows that at a pump power of 60 W and a coupling mirror reflectivity of 96%, a Stokes output with a linewidth of 1.6 kHz and up to 80% optical conversion efficiency can be achieved by reducing the insertion loss of the intracavity. This study provides a promising technical route to achieve high-power ultra-narrow linewidth special wavelength laser radiations.show less

The next generation of high-power lasers enables repetition of experiments at orders of magnitude higher frequency than was possible using the prior generation. Facilities requiring human interv

The next generation of high-power lasers enables repetition of experiments at orders of magnitude higher frequency than was possible using the prior generation. Facilities requiring human intervention between laser repetitions need to adapt in order to keep pace with the new laser technology. A distributed networked control system can enable laboratory-wide automation and feedback control loops. These higher-repetition-rate experiments will create enormous quantities of data. A consistent approach to managing data can increase data accessibility, reduce repetitive data-software development, and mitigate poorly organized metadata. An opportunity arises to share knowledge of improvements to control and data infrastructure currently being undertaken. We compare platforms and approaches to state-of-the-art control systems and data management at high-power laser facilities, and we illustrate these topics with case studies from our community.show less