We propose a spatiotemporal modulation method to achieve super-resolution imaging at a depletion power two orders of magnitude lower than traditional counterpart. By increasing the pulse interval between excitation and depletion lasers, the fluorescence lifetime data contain the spatiotemporal information of confocal and STED photons at the same time. Two kinds of information are bounded by depletion pulse in a period of the pulse trains, and their intensity difference represents the stimulated emission intensity by donut-shaped depletion laser. Finally, low-power STED imaging with high image quality is realized by subtracting the enhanced stimulated emission intensity from the confocal one.
As a near-infrared photosensitizer, IR780 is a promising agent for photodynamic therapy. However, its clinical application was limited by its poor aqueous solubility and chemical stability. Therefore, the purpose of this study was to prepare IR780 encapsulated nanoemulsion (IR780-NE) to enhance the solubility and chemical stability of IR780, using a low-energy emulsion inversion point (EIP) method, which could avoid complex procedure and IR780 degradation during preparation process. The IR780-NE presented a homogeneous and clear appearance, as well as a mean droplet diameter of 38.17 ± 3.59 nm, as determined by dynamic light scattering. The IR780-NE greatly enhanced the chemical stability of IR780, with more than 80% IR780 retained after storage at 25 °C for 4 days. The IR780-NE also showed satisfactory physical stability, with no alteration of mean droplet diameter during storage at 25 °C for 4 days or 4 °C for 30 days. The zeta potential of the IR780-NE was nearly zero (-0.27 ± 2.06 mV), and the ultraviolet-visible light absorption spectrum showed that the near-infrared light absorbing ability of IR780 was not influenced. In conclusion, the IR780-NE is a potential delivery system for the application of IR780 in biological systems.
We proposed a three-wavelength multiplexer/demultiplexer based on the characteristics of resonant coupling between
photonic crystal ring resonator (PCRR) and cavity. The structure composed of one PCRR and three cavities. The
numerical results obtained by the finite-different time-domain (FTDT) method show that it can realize the
demultiplexing of three wavelengths, i.e. 1430nm, 1490nm and 1550nm only by modulating the radius of the cavities.
The designed device not only has a compact size with 12μm×11μm but also a high efficiency, may have potential
applications in the integrated optics fields.