Multi-photon lithography of 3D micro-structures in As₂S₃and Ge₅(As₂Se₃)95 chalcogenide glasses

Processing and fabrication of micro-structures by multiphoton lithography in germanium-doped arsenic selenide

“…All films were placed in light-tight containers and stored in a desiccator for protection from ambient light and moisture. The films were prepared and handled as reported earlier [16][17][18]34].…”

“…The methods of laser exposure and film processing have been described previously but are summarized here for completeness [16][17][18]34]. A mode-locked femtosecond laser (Coherent-Mira, 800-nm center wavelength, pulse width τ p = 120 fs, repetition rate f = 76 MHz) was used to photo-pattern the films.…”

“…Semiconducting photo-patternable multi-component glasses known as chalcogenide glasses (ChGs) possess tunable properties that include excellent IR transparency, large index of refraction, photo-sensitivity, modest coefficients of thermal expansion (CTE), thermo-optic coefficient (dn/dT), and unique optical functionality over a range of form factors and environmental conditions [14]. ChGs have applications in photonic waveguides, sensors, acousto-optics, and optics [14][15][16][17][18].…”

“…Micro-scale 3D devices have function in optics, imaging, sensing, consumer electronics, micro-electromechanical systems, and medicine [16][17][18]. Multiphoton lithography (MPL) has been used to create functional micro-scale three-dimensional (3D) devices in photopolymers, glasses, and composites [19].…”

“…The ChG that has been most used for MPL is thermally deposited arsenic trisulfide (As 2 S 3 ) [15][16][17][18]. As 2 S 3 offers potential for IR applications due to its useful optical bandgap of E g = 2.35 eV (λ 517 nm), high transparency from 620 nm to 11 µm, and large refractive index of n = 2.45  2.53 [15][16][17][18]. As 2 S 3 can be thermally deposited onto substrates as thin photo-sensitive glassy films of molecular clusters consisting of homopolar bonds.…”