Ultrahigh-Q optomechanical crystal cavities fabricated in a CMOS foundry

Author(s)

Benevides, Rodrigo ; Santos, Felipe G. S. ; Luiz, Gustavo O. ; Wiederhecker, Gustavo S. ; Mayer Alegre, Thiago P.

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 7, MAY 30 2017.
• Web of Science Citations: 9

Abstract

Photonic crystals use periodic structures to create frequency regions where the optical wave propagation is forbidden, which allows the creation and integration of complex optical functionalities in small footprint devices. Such strategy has also been successfully applied to confine mechanical waves and to explore their interaction with light in the so-called optomechanical cavities. Because of their challenging design, these cavities are traditionally fabricated using dedicated high-resolution electron-beam lithography tools that are inherently slow, limiting this solution to small-scale or research applications. Here we show how to overcome this problem by using a deep-UV photolithography process to fabricate optomechanical crystals in a commercial CMOS foundry. We show that a careful design of the photonic crystals can withstand the limitations of the photolithography process, producing cavities with measured intrinsic optical quality factors as high as Q(i) = (1.21 +/- 0.02) x 10(6). Optomechanical crystals are also created using phononic crystals to tightly confine the GHz sound waves within the optical cavity, resulting in a measured vacuum optomechanical coupling rate of g(0) = 2 pi x (91 +/- 4) kHz. Efficient sideband cooling and amplification are also demonstrated since these cavities are in the resolved sideband regime. Further improvements in the design and fabrication process suggest that commercial foundry-based optomechanical cavities could be used for quantum ground-state cooling. (AU)

• FAPESP's process: 14/12875-4 - Photonic and phononic crystals
• Grantee: Rodrigo da Silva Benevides
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 12/17765-7 - Nanophotonics in Group IV and III-V semiconductors
• Grantee: Gustavo Silva Wiederhecker
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 12/17610-3 - Optomechanics in photonic and phononic crystals
• Grantee: Thiago Pedro Mayer Alegre
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 16/18308-0 - Quantum optomechanics in microcavities
• Grantee: Rodrigo da Silva Benevides
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/06360-9 - Optomechanical Cavities
• Grantee: Felipe Gustavo da Silva Santos
• Support Opportunities: Scholarships in Brazil - Doctorate