Femtosecond Laser Direct‐Write Plasmonic Nanolithography in Dielectrics

Abstract

Plasmon‐based devices have founded numerous applications in photonics based on optically excited strong near‐field effect at nanoscale. So far, the large‐area fabrication of periodic plasmonic nanostructures is still challenging due to a small write‐field limitation of lithography‐based techniques, especially for metallic substrates. A novel strategy is proposed to fabricate millimeter‐sized patterns of periodic plasmonic nanostructures inside dielectric materials (glass) through a femtosecond laser direct‐write plasmonic nanolithography approach. Noble metal nanoparticles are formed by the ion implantation in glass and reshaped into a nanowire‐like nanoparticles’ assembly by direct writing with femtosecond laser harnessing plasmonic interaction. As‐designed patterns at nanoscale are inscribed by this type of plasmonic lithography to form wires composed of nanoparticles. Examples for applications, the linear dichroism response, and structural color have been achieved by the plasmonic nanogratings buried inside glass (i.e., at subsurface regions). The work opens a new avenue to manipulate metallic nanoparticles in solids by direct plasmonic nanolithography and offers a reliable implementation of large‐area fabrication of plasmonic nanostructures for diverse range of photonic applications.

Ultrafast Laser‐Induced Plasmonic Modulation of Optical Properties of Dielectrics at High Resolution

“…For the induction of nanowires shown in Figure 3a–c, the laser pulse energy was fixed at ≈5.6 nJ, which is much lower than the energy (fluence) required to modify fused silica glass without NPs under the same parameters (≈32 nJ in our experimental conditions; the ablation threshold of silica ≈2 J cm −2 ). [ 40 ] This demonstrates that the state change of the system originates from the near‐field enhanced light‐matter interaction of the LSPR. According to the color change observed under the optical microscope, resulting from different plasmon resonance modes before and after NPs formation and re‐shaping at corresponding scan rates of 5 mm s −1 , 100 µm s −1 , and 10 µm s −1 , the evolution of the NP system can be classified into stages I‐to‐III.…”

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

“…Interestingly, the photothermal reshaping of plasmonic nanostructures by laser pulses can also be realized below the melting point of a bulk metal, as explained by a surface-diffusion model. ,, Besides the laser power, adjusting the laser wavelength and polarization also provides degrees of freedom to control the structural morphologies and resultant color pixels. − Two orthogonal arms of anisotropic plasmonic nanostructures can be separately reshaped by lasers with their polarization along different directions, achieving multiplexed pixels . Instead of writing on the 2D surfaces of different materials, − the structural color prints can alternatively be prepared inside 3D matrices. − The laser printing of plasmonic colors inside transparent Au-nanodisk-embedded polymeric matrices has been demonstrated (Figure c) . The position of the focused laser spot can access a 3D space in different depths inside the polymer with uniformly distributed circular Au nanodisks, creating multiple layers of color patterns inside a single piece of matrix.…”

Tip‐based Lithography with a Sacrificial Layer

“…[1,2] Conventional lithographic technologies like extreme ultraviolet lithography and e-beam lithography offer high resolution but are mainly suitable for high-end applications due to their high cost and time-consuming processes for mass production. This limitation has catalyzed the development of alternative methods, including nanoimprint lithography, [3,4] laser direct writing, [5][6][7][8] nanotransfer printing, [2,9,10] PEEL (photolithography, etching, electron beam deposition, and lift-off) methods, [11,12] and tip-based lithography [13][14][15][16][17][18][19][20][21] However, the fabrication of sub-100nm-scale nanostructures at room temperature under ambient conditions remains challenging. DOI: 10.1002/smll.202309484 Among these techniques, tip-based lithography (a nanolithography method utilizing atomic force microscopy) emerges as a promising approach for fabricating nanostructures without photomasks in ambient conditions.…”