Laser & Optoelectronics Progress, Volume. 60, Issue 13, 1316016(2023)
Development of Femtosecond Laser Direct-Writing Optical Waveguide Devices in Flexible PDMS
Fig. 1. An envisioned example of 3D optical waveguide devices integrated in one flexible PDMS substrate[27]
Fig. 3. AFM of the waveguide cross-section of a quartz glass[40]
Fig. 4. Relative concentration distribution of six ions in crown glass after laser irradiation[66]
Fig. 5. Two types of waveguides in x-cut LiNbO3 written by laser at a pulse energy of 0.2 µJ and different pulse widths[62]. (a) (b) Extraordinary refractive index profile and guided optical mode at a wavelength of 633 nm for a pulse duration of 220 fs, Type-I; (c) (d) extraordinary refractive index profile and guided optical mode at a wavelength of 633 nm for a pulse duration of 1.1 ps, Type-II
Fig. 7. Femtosecond laser direct-writing Type-I optical waveguides in PDMS immersed with photosensitized monomer[27]. (a) PDMS curing; (b) immersing the cured PDMS into photosensitized monomer solution; (c) femtosecond laser direct-writing Type-I optical waveguides; (d) heat treatment to remove residual photosensitized monomer; (e) absorption spectrum of photosensitized monomer phenylacetylene in acetonitrile solvent, purple arrows indicate two-photon and three-photon absorption wavelengths, inset shows the multiphoton polymerization reaction equation of phenylacetylene; (f)(g) top view and cross-sectional view of the Type-I optical waveguide directly written in PDMS by femtosecond laser; (h) plots of optical waveguide width and height as a function of direct-writing depth
Fig. 8. Femtosecond laser direct-writing compound optical waveguide via multiple scanning[28-29]. (a) Schematic of direct-writing optical waveguide by multi-scan stacking method;(b1)-(b3) cross-sectional view (upper) and top view (lower) of the optical waveguide written by single-, double-, and triple-scan stacks; (c) large array of 12 × 12 optical waveguides written directly based on the triple-scan stacking method
Fig. 9. Femtosecond laser direct-writing Type-I optical waveguide in cured PDMS doped with photosensitizer[30-31]. (a) Schematic of 515 nm femtosecond laser direct-writing optical waveguide in flexible PDMS; (b) transmission spectra of PDMS doped with different photosensitizers, inset, cured PDMS bulk after doping with photosensitizer; (c) microscopic near-field images of optical waveguides direct-written under different laser power densities, left, burnt, right, not burnt; (d) two photosensitive mechanisms, namely, cleavage and hydrogen-abstraction; (e) measurement of optical waveguide coupling, transmission loss, and mode field
Fig. 10. Electrode array devices inserted inside the human cochlea[29]. (a) Schematic of a cochlear implant electrode array module inserted inside the human cochlea; (b) cochlear implant module with the PDMS waveguide bundle endoscope
Fig. 11. Simulation and calculation for the input and output imaging signals based on optical waveguide arrays[29]. (a)(b) Input from the MNIST database and refractive index distribution of a 12×12 PDMS waveguide bundle; (c)(d) x-z and y-z propagation profiles along 2 cm propagation length at 600 nm wavelength; (e)(f) output intensity profile after 2 cm and 4 cm propagation length
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Zhi Chen, Lijing Zhong, Mengjia Chen, Yuying Wang, Xiaofeng Liu, Zhijun Ma, Jianrong Qiu. Development of Femtosecond Laser Direct-Writing Optical Waveguide Devices in Flexible PDMS[J]. Laser & Optoelectronics Progress, 2023, 60(13): 1316016
Category: Materials
Received: May. 25, 2023
Accepted: Jun. 19, 2023
Published Online: Jul. 25, 2023
The Author Email: Chen Zhi (zhichen@zhejianglab.edu.cn), Zhong Lijing (zlight.optics@gmail.com)