TY - JOUR
T1 - Amorphous silicon with extremely low absorption
T2 - beating thermal noise in gravitational astronomy
AU - Birney, Ross
AU - Steinlechner, J.
AU - Tornasi, Z.
AU - Macfoy, Sean
AU - Vine, David
AU - Bell, A.S.
AU - Gibson, Desmond
AU - Hough, Jim
AU - Rowan, Sheila
AU - Sortais, P.
AU - Sproules, S.
AU - Tait, S.
AU - Martin, Iain W.
AU - Reid, Stuart
PY - 2018/11/6
Y1 - 2018/11/6
N2 - Amorphous silicon has ideal properties for many applications in fundamental research and industry. However, the optical absorption is often unacceptably high, particularly for gravitational wave detection. We report a novel ion beam deposition method for fabricating amorphous silicon with unprecedentedly low unpaired electron spin density and optical absorption; the spin-limit on absorption being surpassed for the first time. At low unpaired electron density, the absorption is no longer correlated with electron spins, but with the electronic mobility gap. Compared to standard ion beam deposition, the absorption at 1550,nm is lower by a factor of ≈100. This breakthrough shows that amorphous silicon could be exploited as an extreme performance optical coating in near-infra-red applications and it represents an important proof-of-concept for future gravitational wave detectors.
AB - Amorphous silicon has ideal properties for many applications in fundamental research and industry. However, the optical absorption is often unacceptably high, particularly for gravitational wave detection. We report a novel ion beam deposition method for fabricating amorphous silicon with unprecedentedly low unpaired electron spin density and optical absorption; the spin-limit on absorption being surpassed for the first time. At low unpaired electron density, the absorption is no longer correlated with electron spins, but with the electronic mobility gap. Compared to standard ion beam deposition, the absorption at 1550,nm is lower by a factor of ≈100. This breakthrough shows that amorphous silicon could be exploited as an extreme performance optical coating in near-infra-red applications and it represents an important proof-of-concept for future gravitational wave detectors.
U2 - 10.1103/PhysRevLett.121.191101
DO - 10.1103/PhysRevLett.121.191101
M3 - Article
SN - 0031-9007
VL - 121
JO - Physical Review Letters
JF - Physical Review Letters
M1 - 191101
ER -