Direct laser writing regimes for bulk inscription of polarization-based spectral microfilters and fabrication of microfluidic bio/chemosensor in bulk fused silica

Abstract

Laser inscription of form-birefringent nanograting layers inside fused silica by ultrashort (femto-picosecond) laser pulses at 515 nm was studied as a function of laser, average power and pulsewidth in terms of fabrication regimes. Retardance magnitudes were acquired for single birefringent layers inscribed at different laser parameters, enabling fabrication of polarization-based spectral micro-filters in the form of few-layer microdevices and of microfluidic multi-color refractive-index chemo/biosensor.

Nanohydrodynamic Local Compaction and Nanoplasmonic Form-Birefringence Inscription by Ultrashort Laser Pulses in Nanoporous Fused Silica

“…During the last decade, the ultrashort-pulse laser inscription of (sub)microscale birefringent nanograting arrays in bulk dielectrics has emerged as a new promising key-enabling technology for the non-destructive, re-writable fabrication of innovative low-loss macro-and micro-optical devices–polarizers, phase elements, etc. [ 1 , 2 , 3 , 4 , 5 ]. This technology utilizes the birefringence/polarization effect of the bulk anisotropic nanogratings and polarization/interference effects in their multiple layers with overall retardance approaching wavelength scale [ 2 , 5 ], rather than its common irreversible densification- [ 6 ] or void-related refractive-index modulation [ 7 ].…”

“…[ 1 , 2 , 3 , 4 , 5 ]. This technology utilizes the birefringence/polarization effect of the bulk anisotropic nanogratings and polarization/interference effects in their multiple layers with overall retardance approaching wavelength scale [ 2 , 5 ], rather than its common irreversible densification- [ 6 ] or void-related refractive-index modulation [ 7 ]. These underlying effects provide additional flexibility in terms of the design, internal arrangement, and spatial scales of laser-inscribed functional optical elements and the ongoing progress of this technology [ 1 , 2 , 3 , 4 , 5 ].…”

“…This technology utilizes the birefringence/polarization effect of the bulk anisotropic nanogratings and polarization/interference effects in their multiple layers with overall retardance approaching wavelength scale [ 2 , 5 ], rather than its common irreversible densification- [ 6 ] or void-related refractive-index modulation [ 7 ]. These underlying effects provide additional flexibility in terms of the design, internal arrangement, and spatial scales of laser-inscribed functional optical elements and the ongoing progress of this technology [ 1 , 2 , 3 , 4 , 5 ]. Meanwhile, many conjugate physical processes—(non)linear laser focusing [ 8 ], nanoplasmonic arrangements [ 9 ], and nanoscale material transport mechanisms [ 10 ]—in the focal region during material/refractive-index nanograting formation are still poorly understood.…”

Hierarchical Multi-Scale Coupled Periodical Photonic and Plasmonic Nanopatterns Inscribed by Femtosecond Laser Pulses in Lithium Niobate

“…Flexible ultrashort-pulse laser nanopatterning of bulk dielectrics appears as a key enabling technology for next generations of all-dielectric metamaterial platforms made of multiple stacks of different functional metasurfaces. Though these opportunities for versatile nanoscale light control and manipulation are still emerging, various laser nanopatterning modalities have already been developed to produce in dielectric media high-contrast refractive index structures based on atomistic densification [ 1 , 2 ], two-photon polymerization [ 3 ], nano-ablation [ 4 , 5 ], periodic nanoscale material self-organization and form-birefringence [ 6 , 7 , 8 ] for well-established applications in direct laser writing (inscription) of light waveguides [ 9 ] and more complex functional morphologies [ 2 ], hollow optical memory bits [ 4 ], microfluidic channels [ 10 ] and polarizing optical elements and devices [ 11 , 12 , 13 ]. Meanwhile, novel promising nanopatterning modalities based on delicate and precise ultrashort-pulse (femtosecond or picosecond, fs/ps) laser inscription in bulk dielectrics are still under intense scientific studies, being highly challenging for accurate fabrication and informative characterization on this dielectric platform because of their mesoscopic, transient and buried character.…”

Ferroelectric Nanodomain Engineering in Bulk Lithium Niobate Crystals in Ultrashort-Pulse Laser Nanopatterning Regime

“…During the last two decades, direct laser writing emerged as versatile tool in nano- and micro-fabrication of integrated photonic circuits, Bragg gratings, optical memory bits, microfluidic and optofluidic channels, phase and polarizing elements and devices in bulk dielectrics [ 1 , 2 , 3 , 4 , 5 ]. Inscription in a homogeneous dielectric medium requires a formation of a new high-contrast refractive-index interface, possible via densification in silica materials [ 6 , 7 ] and rarefaction in other dielectrics [ 8 ], boosting empty nanovoids [ 9 ] or drilling of hollow microchannels [ 10 ].…”