In this Letter, we analyze the near-field diffraction pattern produced by chirped gratings. An intuitive analytical interpretation of the generated diffraction orders is proposed. Several interesting properties of the near-field diffraction pattern can be determined, such as the period of the fringes and its visibility. Diffraction orders present different widths and also, some of them present focusing properties. The width, location, and depth of focus of the converging diffraction orders are also determined. The analytical expressions are compared to numerical simulation and experimental results, showing a high agreement.
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http://dx.doi.org/10.1364/OL.41.004091 | DOI Listing |
Plasmonic structured illumination microscopy (PSIM) is a super-resolution technique that utilizes surface plasmon polaritons (SPPs) with higher frequency as the structured light; thus, it is able to break the diffraction limit with a 3-4 times resolution enhancement. However, the low efficiency of near-field fluorescence collection results in a low imaging signal-to-noise ratio (SNR) of PSIM. In this paper, we propose a method to enhance the performance of PSIM with surface plasmon coupled emission (SPCE).
View Article and Find Full Text PDFNano Lett
January 2025
Regensburg Center for Ultrafast Nanoscopy (RUN) and Department of Physics, University of Regensburg, 93040 Regensburg, Germany.
Detecting electromagnetic radiation scattered from a tip-sample junction has enabled overcoming the diffraction limit and started the flourishing field of polariton nanoimaging. However, most techniques only resolve amplitude and relative phase of the scattered radiation. Here, we utilize field-resolved detection of ultrashort scattered pulses to map the dynamics of surface polaritons in both space and time.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
School of Optoelectronic Engineering, Xidian University, Xi'an 710071, China.
Compared with traditional far-field objective lenses, microparticle lenses have a distinct advantage of nonobservance of the diffraction limit, which has attracted extensive attention for its application in subwavelength photolithography and super-resolution imaging. In this article, a complete simulation model for a microparticle lens assisted microscopic imaging system was built to analyze the imaging characteristics of any shape of microparticle lens. With this model, we simulated the resolution of a conventional objective lens, a microsphere lens and a hollow microsphere lens, which verified the correctness of our simulation model and demonstrated the super-resolution imaging ability of microsphere lenses.
View Article and Find Full Text PDFNanophotonics
April 2024
School of Electronic and Information Engineering, and School of Cyber Science and Technology, Beihang University, Beijing, China.
Understanding the ultrafast excitation, detection, transportation, and manipulation of nanoscale spin dynamics in the terahertz (THz) frequency range is critical to developing spintronic THz optoelectronic nanodevices. However, the diffraction limitation of the sub-millimeter waves - THz wavelengths - has impaired experimental investigation of spintronic THz nano-emission. Here, we present an approach to studying laser THz emission nanoscopy from W|CoFeB|Pt metasurfaces with ∼60-nm lateral spatial resolution.
View Article and Find Full Text PDFNanophotonics
May 2024
Department of Chemistry, University of California, Irvine, Irvine, CA, USA.
Nanostructured plasmonic surfaces allow for precise tailoring of electromagnetic modes within sub-diffraction mode volumes, boosting light-matter interactions. This study explores vibrational strong coupling (VSC) between molecular ensembles and subradiant "dark" cavities that support infrared quadrupolar plasmonic resonances (QPLs). The QPL mode exhibits a dispersion characteristic of bound states in the continuum (BIC).
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