Nanoscale Photonics 

We perform cutting-edge research on micro-photonic technologies, utilising SNAP technology to create versatile photonic devices with an array of applications


Our experienced research team is pushing at the frontiers of current scientific knowledge surrounding microphotonic technologies. While these technologies have allowed us to fabricate devices with remarkable precision, a much greater precision is necessary if we are to unlock their full range of potential applications. 

We are working on a new photonic technology, Surface Nanoscale Axial Photonics (SNAP), which will overcome current limitations. This technology and its unprecedented precision will make many of the barriers to revolutionary advances in a range of fields a thing of the past. 

Areas that will benefit from this technology include telecommunications, ultraprecise sensing, quantum computing, networks, optomechanics, optofluidics and other fields of engineering and science. 

Our Research

Highlights of our and discoveries in 2019 included: 

  • The effects and applications of slow cooking SNAP microresonators 

  • New SNAP fabrication methods employing femtosecond lasers and fibre bending 

  • Novel methods of lithography 

  • First successful demonstration of a four-port resonant SNAP device 

  • Theoretical investigations of nonlinear SNAP devices 

  • Development of SNAP microresonator frequency comb generators 

  • Demonstrating the possibility of microscale light-by-light transportation.

Our Projects

Slow cooking of optical microresonators

Silica and water are known as exceptionally inert chemical materials, while the mechanism of their interaction is not completely understood. We show that the effect of this interaction can be significantly enhanced by the optical whispering gallery modes (WGMs) propagating at a silica microcapillary filled in with water. 

Our experiments demonstrate that WGMs, which are maintained inside the microcapillary and heat water over several hours, induce permanent change into silica material. This change results in the nanoscale variation of the microcapillary effective wall thickness and creation of WGM microresonators having promising applications in optical signal processing and microfluidic sensing.  

Overall, the discovered effect paves a way to the ultraprecise fabrication of resonant optical microdevices as well as suggests an ultra-accurate method for the characterization of physical and chemical processes at the solid-liquid interfaces. 

G. Gardosi, B. J. Mangan, G. S. Puc, and M. Sumetsky, ACS Photonics 8, 436 (2021)

Controlled transportation of light by light at the microscale

We show how light can be controllably transported by light at microscale dimensions. We design a miniature device which consists of a short segment of an optical fibre coupled to transversally-oriented input-output microfibers. A whispering gallery soliton is launched from the first microfiber into the fibre segment and slowly propagates along its mm-scale length. The soliton loads and unloads optical pulses at designated input-output microfibers. 

The speed of the soliton and its propagation direction is controlled by the dramatically small, yet feasible to introduce permanently or all-optically, nanoscale variation of the effective fibre radius.  

M. Crespo-Ballesteros and M. Sumetsky, Phys. Rev. Lett. 126, 153901 (2021).

In situ observation of slow and tunnelling light at the cutoff wavelength of an optical fibre

Slow waves and tunnelling waves can meet at the cutoff wavelengths and/or transmission band edges of optical and quantum mechanical waveguides. The experimental investigation of this phenomenon, previously performed using various optical microstructures, is challenged by fabrication imperfections and material losses. Here, we demonstrate this phenomenon in situ for whispering gallery modes slowly propagating along a standard optical fibre, which possesses the record uniformity and exceptionally small transmission losses. 

Slow axial propagation dramatically increases the longitudinal wavelength of light and allows us to measure nanosecond-long tunnelling times along tuneable potential barriers having the width of hundreds of microns. This demonstration paves a simple and versatile way to investigate and employ the interplaying slow and tunnelling light. 

Y. Yang and M. Sumetsky, Opt. Lett. 45, 762 (2020). 

Mahaux-Weidenmüller approach to cavity quantum electrodynamics and complete resonant down-conversion of the single-photon frequency

It is shown that a broad class of cavity quantum electrodynamics (QED) problems—which consider the resonant propagation of a single photon interacting with quantum emitters (QEs), such as atoms, quantum dots, or vacancy centres—can be solved directly without application of the second quantization formalism. 

The developed approach dramatically simplifies the analysis of complex cavity QED systems.  As an example, we consider an optical cavity having two modes resonantly coupled to electronic transitions of N three-level QEs. 

It is shown that the described structure is the simplest realistic structure which enables the down-conversion of the single-photon frequency with the amplitude approaching unity in the absence of the external driving field and sufficiently small cavity losses and QE dissipation. Overall, the simplicity and generality of the developed approach suggest a practical way to identify and describe new phenomena in cavity QED. 

M. Sumetsky, Phys. Rev. A 45, 762 100, 013801 (2019). 


Academic Staff
  • Prof. Sumetsky, Misha 
Research Fellows
  • Dr. Crespo-Ballesteros, Manuel 
  • Dr. Tokmakov, Kirill 
  • Dr. Toropov, Nikita 
  • Dr. Yang, Yong 
Research PhD Students
  • Ms. Gardosi, Gabriella 
  • Mr. Vassiliev, Victor 
  • Ms. Yu, Qi 
  • Mr. Zaki, Sajid