1. Integrated Polarisation Control in Microlens Arrays: Performance at Visible-Ir Spectral Ranges
- Author
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Haoran Mu, Daniel Smith, Tomas Katkus, Darius Gailevicius, Mangirdas Malinauskas, Yoshiaki Nishijima, Paul R Stoddart, Dong Ruan, Meguya Ryu, Junko Morikawa, Taras A Vasiliev, Valeri Lozovski, Daniel Moraru, Soon Hock Ng, and Saulius Juodkazis
- Subjects
optics - Abstract
Microlens arrays (MLAs) which are increasingly popular micro-optical elements in compact integrated optical systems were fabricated by femtosecond direct laser write (fs-DLW) technique in the low-shrinkage SZ2080TM photoresist. High fidelity definition of 3D surfaces on IR transparent CaF2 substrates allowed to achieve ∼ 50% transmittance at chemical fingerprinting spectral region 2-5 μm wavelengths since MLAs were only ∼ 10 μm high corresponding to the numerical aperture of 0.3 (the lens height is comparable with the IR wavelength). To combine diffractive and refractive capabilities in miniaturised optical setup, a graphene oxide (GO) grating acting as a linear polariser was also fabricated by fs-DLW by ablation of a 1 μm-thick GO thin film. Such an ultra-thin GO polariser can be integrated with the fabricated MLA to add dispersion control at the focal plane. Pairs of MLAs and GO polarisers were characterised throughout visible-IR spectral window and numerical modeling was used to simulate their performance. Good match between experimental results of MLA focusing and simulations was achieved.
- Published
- 2023