We propose and experimentally demonstrate an alternative WGR coupling scheme that is easy to make, requires little alignment, and is both convenient and stable with no need for phase matching. It relies on cavity enhanced Rayleigh scattering. This is the first, single-ended, fiber-based optical nano-antenna that can be used to simultaneously excite and collect light from the WGMs of a microresonator, coupling efficiency as high as 13% is observed, making it very promising for optical sensing applications or cQED.
The particular properties of hollow whispering gallery resonators should lead to the advancement of bio- and chemical sensing applications. In this talk, we report on the fabrication of, and mode propagation in, hollow, thin-walled microcavities, known as microbubbles or microbottles, which are made from microcapillaries that are pretapered, then heated using a CO2 laser while flowing air through them. The resulting cavity consists of a thin glass shell supported on a hollow stem through which fluid can flow. Whispering gallery modes supported in the wall of the cavity create an evanescent field extending from both the inner and outer surfaces. For higher order modes, and playing with material refractive indices, the system can be engineered so that most of the optical energy extends into the contained fluid, thereby allowing for strong interactions to be present; such a cavity is called a quasi-droplet. Even tiny changes to the fluid, such as the presence of nanoparticles, can lead to a significant shift of the resonance frequencies of the whispering gallery modes. These strongly interacting quasi-droplets make hollow microresonators uniquely suited for sensing applications.
In recent years, whispering gallery mode (WGM) devices have extended their functionality across a number of research fields from photonics device development to sensing applications. Here, we will discuss some such recent applications using ultrahigh Q-factor hollow resonators fabricated from pretapered glass capillary. We will discuss device fabrication and different applications that can be pursued such as bandpass filtering, nanoparticle detection, and trapping. Finally, we will introduce our latest results on visible frequency comb generation.
In recent years, whispering gallery mode devices have extended their functionality across a number of research fields from photonics to sensing applications. Here, we will discuss environmental sensing applications, such as pressure, flow, and temperature using ultrahigh Q-factor microspheres fabricated from ultrathin optical fiber and microbubbles fabricated from pretapered glass capillary. We will discuss device fabrication and the different types of sensing that can be pursued using such systems. Finally, we will introduce the concept of using cavity ring-up spectroscopy to perform dispersive transient sensing, whereby a perturbation to the environment leads to a frequency mode shift, and dissipative transient sensing, which can lead to broadening of the mode, in a whispering gallery mode resonator.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.