Probe phase shift: Relationship with the Local Density Of Optical State (LDOS)
2016 Progress in Electromagnetics Research Symposium
In this letter, we investigate theoretically the relation between SNOM images and photonics density of states (DOS) in a novel experimental set up. We show that under some conditions it is theoretically possible to access optically to a quantitative measurement of the projected Local Density Of States (p-LDOS). The experimental set up is based on the measurement of the phase lag at the level of the diffusing head scan. The detail theory including tip sample interaction, improve the general comprehension of the SNOM images. Traditionally associated to a LDOS measurement, the SNOM measurement involve a convolution of the local field and the LDOS. To access to a quantitative measure of the LDOS optically, is a difficult task. Here we will show that to access to the LDOS directly is possible through an optical measurement related to an heterodyne phase measurement by employing Trans-scattering-type scanning near-field optical microscopy (TS-SNOM).