Woolf, DavidHui, Pui-ChuenIwase, EijiKhan, MugheesRodriguez, Alejandro W.Deotare, ParagBulu, IrfanJohnson, Steven G.Capasso, FedericoLoncar, Marko2019-09-172013Woolf, David, Pui-Chuen Hui, Eiji Iwase, Mughees Khan, Alejandro W. Rodriguez, Parag Deotare, Irfan Bulu, Steven G. Johnson, Federico Capasso, and Marko Loncar. 2013. “Optomechanical and Photothermal Interactions in Suspended Photonic Crystal Membranes.” Optics Express 21 (6): 7258. https://doi.org/10.1364/oe.21.007258.1094-4087http://nrs.harvard.edu/urn-3:HUL.InstRepos:41371341We present here an optomechanical system fabricated with novel stress management techniques that allow us to suspend an ultrathin defect-free silicon photonic-crystal membrane above a Silicon-on-Insulator (SOI) substrate with a gap that is tunable to below 200 nm. Our devices are able to generate strong attractive and repulsive optical forces over a large surface area with simple in-and out-coupling and feature the strongest repulsive optomechanical coupling in any geometry to date (g(OM)/2 pi approximate to -65 GHz/nm). The interplay between the optomechanical and photo-thermal-mechanical dynamics is explored, and the latter is used to achieve cooling and amplification of the mechanical mode, demonstrating that our platform is well-suited for potential applications in low-power mass, force, and refractive-index sensing as well as optomechanical accelerometry.en-USJournal Article2019-09-1710.1364/OE.21.007258