Polarization Properties in Apertureless-Type Scanning Near-Field Optical Microscopy

Abstract

Polarization properties of apertureless-type scanning near-field optical microscopy (a-SNOM) were measured experimentally and were also analyzed using a finite-difference time-domain (FDTD) simulation. Our study reveals that the polarization properties in the a-SNOM are maintained and the a-SNOM works as a wave plate expressed by a Jones matrix. The measured signals obtained by the lock-in detection technique could be decomposed into signals scattered from near-field region and background signals reflected by tip and sample. Polarization images measured by a-SNOM with an angle resolution of 1°are shown. FDTD analysis also reveals the polarization properties of light in the area between a tip and a sample are p-polarization in most of cases.

Quantifying Polymer Chain Orientation in Strong and Tough Nanofibers with Low Crystallinity: Toward Next Generation Nanostructured Superfibers

“…197 Polarization of the light also deteriorates as the signal propagates through probe. 198 As a consequence, the practical resolution limit of a-NSOM is on the order of 50 nanometers, when used with visible light, 197 long scan times are needed, and vibrational spectroscopies such as FTIR are not practical for submicron feature sizes. 197 Although Raman spectroscopy using a-NSOM was demonstrated for some material systems, 199 it is generally impractical due to weak signal.…”

Concentric Nano Elliptical Apertures Array Tip for Intensity Enhancement in Scanning Near-Field Optical Microscopy for Imaging

“…Ⅲ contains the numerical results, showing the maximum output (intensity) and the spatial resolution values at the desired impinged angle of θ=70 focused on MUT surface. The obtained spatial resolution values by CNEAAT at the four impinged scanned angles are underneath of 50 nm and improves the least limit of typical SNOM tips resolution in imaging applications [6]. Figure 7 shows the maximum output (intensity) value at the desired impinged angle of θ=70 and primitive angle of ϕ=0.…”

“…The desired radius is equaled to 138nm which is in subwavelength scale of incident photons at frequency of 800 THz (free space wavelength of 375 nm), and reduces the scattering while focusing output beam on the surface of MUT. To maintain efficacious interaction and reduce attenuation, the space between CNEAAT and MUT is set to 50nm in subwavelength profile compared to the incident photons wavelength (375nm), and five times greater than the least fabricable gap between the tip and the material [6]. The achieved intensity by impinged output beam is relevant to the near-field characteristics and found efficient to affect the spatial resolution, that is unequally affiliated to SNOM.…”

“…Consequently, the major perspective of this article is the accurate explanation of the manipulated wave equations to excite the CNEAAT and acquiring theoretically the ascertained notation of the generated E-fields among the interacted media. The importance of the article is introducing an array tip totally different from the previous presented designs by [3]- [5] in view of the apertures and the geometry, which is discovered as the research preponderance in our design for the authentic evaluation of the results [3]- [6]. The steered impinged beam at special elevation angle with the foremost optical characteristics is the most proper option for focusing on the inserted MUT in cylindrical reservoir in near-field [4]- [8].…”

Trace of evanescent wave polarization by atomic vapor spectroscopy

“…Reported methods are based on far-field scattered light detection from the nearfield area between tips and nanometric samples. This method faces different problems, such as reference scattering from the background and unequal farfield leakage scattering of different near-field modes [22,23].…”