Near field scanning optical microscopy (NSOM) is an advanced imaging technique used to observe and study nanostructures and materials at the nanoscale level. NSOM combines elements of microscopy and spectroscopy to achieve high resolution imaging of samples in the near-field region by exploiting the properties of light.
In NSOM, a sharp probe tip with a diameter of just a few nanometers is used, which scans the surface of the sample in close proximity. This tip acts as a near-field aperture, and it can either be illuminated or used for detecting the near-field signal from the sample. The key principle behind NSOM is the localized interaction between the probe tip and the sample, resulting in an enhanced spatial resolution beyond the diffraction limit imposed by classical optical microscopy.
By utilizing various optical techniques such as reflection, absorption, and fluorescence, NSOM allows researchers to obtain real-time, high-resolution images with spatial resolution down to tens of nanometers, providing detailed information about the sample surface and its properties. Furthermore, NSOM enables spectroscopic analysis by collecting signals generated at the nanoscale.
NSOM has found applications in diverse fields such as material science, biology, and semiconductor research. It offers insights into nanoscale phenomena, such as molecular interactions, surface plasmon resonance, and local optical properties, facilitating the understanding of complex systems and aiding in the development of nanotechnology-based devices.
