Development of atomically thin optical devices with graphene for astronomical applications

High-speed atomic oxygen (AO) irradiation tests were performed for free-standing graphene membranes to investigate the degradation in terms of mechanical intensity for astronomical applications. The high-speed AO was irradiated with a typical velocity of 5 km/s and fluence values of 3×10¹⁵, 1×10¹⁶, 3×10¹⁶, and 1×10¹⁷ atoms/cm². Two kinds of samples were prepared using single- and bi-layer graphene sheets with through-hole patterns with diameters of 10 µm and 10-200 µm, respectively. Consequently, the yield rate is found to be approximately 90% and 100% for the single- and bi-layer freestanding graphene samples, respectively. Almost all ruptured events occurred after the minimum fluence of 3E+15 atoms/cm². The results suggest that the lifetime of the free-standing graphene structure can be longer by increasing the number of layers or any other causes such as accelerated metal outgassing contaminants remaining the vacuum chamber and detonation waves are not negligible and almost no damages are seen through the high-speed AO irradiation up to the fluence value of 1×10¹⁷ atoms/cm². To improve the sensitivity, our original transfer method was introduced and we fabricated 300/900 µm diameter free-standing single-/bi-layer graphene structures successfully. Additionally, we confirmed that our technique can be applied to ground-based applications such as high-sensitivity graphene Transmission Electron Microscopy (TEM) support films.