Far-Field and Non-Intrusive Optical Mapping of Nanoscale Structures

Abstract

Far-field high-density optics storage and readout involve the interaction of a sub-100 nm beam profile laser to store and retrieve data with nanostructure media. Hence, understanding the light–matter interaction responding in the far-field in such a small scale is essential for effective optical information processing. We present a theoretical analysis and an experimental study for far-field and non-intrusive optical mapping of nanostructures. By a comprehensive analytical derivation for interaction between the modulated light and the target in a confocal laser scanning microscopy (CLSM) configuration, it is found that the CLSM probes the local density of states (LDOSs) in the far field rather than the sample geometric morphology. With a radially polarized (RP) light for illumination, the far-field mapping of LDOS at the optical resolution down to 74 nm is obtained. In addition, it is experimentally verified that the target morphology is mapped only when the far-field mapping of LDOS coincides with the geometric morphology, while light may be blocked from entering the nanostructures medium with weak or missing LDOS, hence invalidating high-density optical information storage and retrieval. In this scenario, nanosphere gaps as small as 33 nm are clearly observed. We further discuss the characterization for far-field and non-intrusive interaction with nanostructures of different geometric morphology and compare them with those obtainable with the projection of near-field LDOS and scanning electronic microscopic results.

On‐Demand Subwavelength‐Scale Light Sculpting Using Nanometric Holograms

“…The structured light has been applied to control nanostructures (particles), [32,33] Bose-Einstein condensates, [34] electric currents, [35] etc., and led to intriguing spin-orbit couplings when the structured light meets structured materials. [36,37] Therefore, light sculptings are crucial in many aspects of scientific research.…”

面向光信息存储的小尺寸光场研究进展

“…(a) Variation of focal spot size and its evolution; (b) division of resolution region 图 8 月牙形锐边衍射生成超振荡点 ［66］ Fig. 8 Crescentshaped sharp edge aperture generating superoscillating spot [66] 1813012 -7 [70] ; (b) setup of improved CLSM and imaging comparison of improved and conventional CLSM [72] ; (c) PSFs distribution of CLSM, experimental and simulated results of LDOS mapping [73] 捕获、 抽取、 测量及控制等产生了极大影响。 [78] ; (b) intensity distribution of AAB and transverse intensity patterns of vectorial structured AABs [79] ; (c) intensity profiles of RPCPVB propagating at different propagation distances [80] 11 Focusing of Bessel spot array and superoscillating. (a) Bessel spot array generating device and experimental results [26] ; (b) device and experimental results for generating superoscillating optical spots by Bessel beam [27] 特邀综述 focal field distribution [82] ; (d) -(f) SEM diagram of BP binary optical lens and its focal field distribution [24] ; (g) -(i) schematic diagram, SEM image and focal field distribution of BAP binary optical lens [35] 特邀综述 diffraction solid needle of ONSOL [83] ; (d)-(f) schematic diagram, SEM image and the generated hollow superdiffraction needle of binary optical lens based on NASC [85] ; (g) -(i) schematic diagram, SEM image of SCL and the resulting hollow superdiffraction needle [86] 1813012 -12 polarized Bessel -Gaussian beam regulated by binary optical elements and focal spot distribution [30] ; (b) schematic diagram of azimuthally polarized beam regulated by a binary vortex phase plate and focal spot distribution of different polarized beams [87] ;…”