Leveraging on ENZ Metamaterials to Achieve 2D and 3D Hyper‐Resolution in Two‐Photon Direct Laser Writing

Abstract

A novel technique is developed to improve the resolution of two‐photon direct laser writing lithography. Thanks to the high collimation enabled by extraordinary εNZ (near‐zero) metamaterial features, ultrathin dielectric hyper‐resolute nanostructures are within reach. With respect to the standard direct laser writing approach, a size reduction of 89% and 50%, in height and width respectively, is achieved with the height of the structures adjustable between 5 and 50 nm. The retrieved 2D fabrication parameters are exploited for realizing extremely thin all‐dielectric metalenses tailored through deep machine learning codes. The hyper‐resolution achieved in the writing process enables the fabrication of a highly detailed dielectric 3D bas‐relief (with full height of 500 nm) of Da Vinci's “Lady with an Ermine”. The proof‐of‐concept results show intriguing cues for the current and trendsetting research scenario in anti‐counterfeiting applications and ultracompact photonics, paving the way for the realization of all‐dielectric and apochromatic ultrathin imaging systems.

Photo-Aligned Nematic Liquid Crystals Enable the Modulation of Thermoplasmonic Heating

“…[1][2][3][4] while for different geometries more complex theoretical models are required. Nowadays, the thermoplasmonic heating is used in several research fields such as high precision medicine [5][6][7], electronics [8][9][10] optics [11][12][13], biology [14,15], and catalysis [16,17]. All above applications are based on the possibility to finely tune the photo-thermal efficiency of the NPs that can be done by acting on several control parameters such as the intensity of the impinging beam [1][2][3][4], the number (N) of involved NPs, and the dielectric function of the surrounding medium ε H [18].…”

Tuning Cholesteric Selective Reflection In Situ Upon Two‐Photon Polymerization Enables Structural Multicolor 4D Microfabrication

“…[1][2][3] Among the different technologies, two-photon direct laser writing (DLW) is nowadays one of the best techniques to pattern metallic nanoparticles in complex geometry [4][5][6][7][8][9][10][11] and to nano-fabricate polymeric 3D structures. [12][13][14][15][16][17][18][19][20][21] Briefly, a near infra-red (NIR) ultrafast laser, with high peak power, is tightly focused inside a UV-sensitive photoresist to promote highly localized photochemical reactions through the simultaneous absorption of two (or more) photons. As a third-order non-linear optical process, two-photon absorption (TPA) cross-section depends on the square of the intensity of the laser beam.…”

Controllable Fast and Slow Light in Photonic-Molecule Optomechanics with Phonon Pump

“…Figure 1 is the photonic-molecule optomechanical system, including two coupled whispering-gallery-mode (WGM) cavities [ 21 , 32 , 53 , 54 , 55 ], where the optomechanical cavity with the decay rate and frequency is evanescently coupled to a tapered fibre. The radiation pressure force arriving from the pump laser field coupled into the optomechanical cavity will induce the radial breathing mode (i.e., the mechanical mode with frequency and damping rate ).…”