title: Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation.
abstract: We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm. A key aspect of such a nanofabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. Moreover, the single-shot fabrication makes it immune to mechanical instabilities and other fabrication imperfections. Such periodic nano-craters on nanofiber, act as a 1-D PhC and enable strong and broadband reflection while maintaining the high transmission out of the stopband. We also present a method to control the profile of the nano-crater array to fabricate apodized and defect-induced PhC cavities on the nanofiber. The strong confinement of the field, both transverse and longitudinal, in the nanofiber-based PhC cavities and the efficient integration to the fiber networks, may open new possibilities for nanophotonic applications and quantum information science.
authors.affiliation: Center for Photonic Innovations, University of Electro-Communications.
authors.forename: Kali Prasanna
authors.initials: KP
authors.lastname: Nayak
authors.affiliation: Center for Photonic Innovations, University of Electro-Communications.
authors.forename: Jameesh
authors.initials: J
authors.lastname: Keloth
authors.affiliation: Center for Photonic Innovations, University of Electro-Communications; k.hakuta@cpi.uec.ac.jp.
authors.forename: Kohzo
authors.initials: K
authors.lastname: Hakuta
mesh_terms: D003460:Crystallization; D004867:Equipment Design; D007834:Lasers; D057139:Nanofibers / Q000737:chemistry*; D053758:Nanoparticles; D055095:Optics and Photonics / Q000295:instrumentation*