3D nano surface profilometry by combining the photonic nanojet with interferometry

Sub-diffraction surface topography measurement using a microsphere-assisted Linnik interferometer

“…By analogy with a classical lens, the position of the photonic nanojet could be considered as being at the image focus point of the microsphere. This suggests that imaging with a microsphere should also be possible with a lateral resolution limit that is smaller than the classical diffraction spot size 8 . The analogy with geometrical optics also suggests, figure 8(a), the formation of a virtual image.…”

“…To demonstrate 3D super-resolution, the choice of the sample is not simple. 3D structures that have been proposed in the literature consist of the periodic line structures of a stripped Blu-Ray DVD disk (spacing of 112 nm) 6,7 , microelectronic structures in a CPU chip 5 , a VLSI STR10-1000P silicon test pattern, composed of 5 µm wide, 100 nm high square structures with a pitch spacing of 5 µm 4 and periodic square grating 3D test patterns 8 . In the present work, the latter type of reference gratings was used (prototype RS-N gratings from SiMETRICS GmbH) consisting of a series of sub-gratings with pitch values varying from 300 nm to 6 µm.…”

“…In the field of high resolution 2D imaging, an important technique introduced several years ago is the use of a microsphere placed on the sample in front of the microscope objective, with a claimed lateral resolution of 50 nm in the best conditions 5 . More recently, in 2016, the microsphere technique was successfully combined with interferometry by several groups in a major step forward in reducing the gap between lateral resolution and axial measurement sensitivity [6][7][8] . In this paper we present some of our own first results of combining the microsphere technique with a white light Linnik interferometer and demonstrate a lateral resolution of /4 and an axial measurement sensitivity of several nm.…”

Resolution enhancement through nearfield-assistance in interference microscopy

“…This was first reported by Wang et al [26] using a white light interferometer. In [11,16,17] measurement results are presented, which successfully demonstrate the super-resolution by microspheres in interferometric systems of different types. The resulting access to high-frequency image information can be used for profilometry [18,20] and to characterize nanomaterials [13].…”

All-dielectric concentration of electromagnetic fields at the nanoscale: the role of photonic nanojets

“…More systematic studies as well as the applications of microsphere-based (or the derivatives of microspheres such as liquid droplets and microbers) imaging can be found extensively in the mainstream optics and photonics journals. 48,[180][181][182][183][184][185][186][187][188] Different than other super-resolution imaging techniques like hyperlens and superlens, [189][190][191] super-oscillation lens, 17,[192][193][194] and uorescence-based modalities, 195,196 the underlying physics of imaging beyond the Rayleigh limit via dielectric microspheres has not been completely revealed yet, although there was a study that claimed that it is due to the FWHM of PNJs. 31 Maslov et al investigated the theoretical limits of resolution available in microsphere-based nanoscopy using incoherent point emitters in the air.…”