Mid-Infrared Photonics

Benjamin Eggleton, Darren Hudson, Tomonori Hu

Why mid-IR?

The mid-infrared wavelength range (3-50 microns) is an extremely useful range of the electromagnetic spectrum. In this range, many molecules exhibit strong, fundamental ro-vibrational absorption. This fact has lead to a drive to develop molecular sensing platforms using mid-IR light. One major roadblock to achieving such devices, however, is the current state of broadband sources in the mid-IR. One of the main goals of the CUDOS mid-IR project is to lead the way in developing these novel sources of light on a compact chip-scale platform. This platform will then be used to demonstrate the usefulness of these devices for sensing applications such as breath analysis, airport security screening, food quality monitoring, and livestock health monitoring.

The Platform

We are currently investigating a number of platforms for developing broadband, mid-IR light on a chip using nonlinear waveguides. Silicon-on-Sapphire (SOS) is being pursued in collaboration with industry partner Silanna, as it exhibits a high nonlinearity and low-loss in the range from 3-5 micron. Simultaneously we are investigating chalcogenide based planar waveguides in collaboration with the Australian National University.

A recent result from the mid-IR lab demonstrated low-loss propagation in SOS waveguides at various wavelengths in the mid-IR [1]. Future work involving SOS waveguides will focus on the nonlinear propagation characteristics of pulses and the spectral expansion through various processes.

We are also pursuing broadband light generation using a complimentary platform: tapered optical fibers based on highly nonlinear glasses such as Arsenic-Sulphide and Arsenic-Selenide. Using the optical fiber tapering facility at the University of Sydney we can build devices with extreme nonlinearity that exhibit similar effects to those observed on chip-waveguide architectures. One of our recent results using a tapered Arsenic-Sulphide fiber produced the lowest reported power for octave-spanning spectral generation [2]. In this demonstration, more than 1 octave of spectral bandwidth was generated using pulses with only 150 W peak power (3 mW average power).

The laboratory

The mid-IR laboratory is housed within the School of Physics and is comprised of 4 main lab sections. Each of these labs are used for specific experiments including optical fiber tapering, construction of rare-earth doped fiber lasers, probing of chip waveguides using a tunable OPA laser system (see picture), and measurement of waveguide loss using quantum cascade lasers.

OPA Laser

The tunable OPA laser facility allows for a wide range of nonlinear optics experiments in the mid-IR. Computer-controlled precision coupling stages allow for precise and stable alignment into waveguides.

Student Opportunities

Students working in the mid-IR laboratory are afforded the opportunity to develop rigorous scientific skills and deep physical understanding while contributing to cutting edge research. The skills gained by our students not only help launch them into a wide range of physics careers, but also translate well to a variety of fields that involve critical thinking and problem solving.

Tomonori H

CUDOS graduate student Tomonori Hu works on a rare-earth fiber laser operating in the Mid-IR. Rare-earth fiber lasers offer unique laser characteristics in the mid-IR such as high power, high beam quality, and potentially short pulse operation.


  1. Neetesh Singh, Alvaro Casas-Bedoya, Darren D. Hudson, Andrew Read, Eric Mägi, and Benjamin J. Eggleton,
    "Mid-IR absorption sensing of heavy water using a silicon-on-sapphire waveguide,"
    Opt. Lett. 41, 5776-5779 (2016)
  2. Neetesh Singh, Darren D. Hudson, Yi Yu, Christian Grillet, Stuart D. Jackson, Alvaro Casas-Bedoya, Andrew Read, Petar Atanackovic, Steven G. Duval, Stefano Palomba, Barry Luther-Davies, Stephen Madden, David J. Moss, and Benjamin J. Eggleton,
    "Midinfrared supercontinuum generation from 2 to 6 a um silicon nanowire,"
    Optica 2, 797-802 (2015)
  3. Neetesh Singh, Darren D. Hudson, and Benjamin J. Eggleton,
    "Silicon-on-sapphire pillar waveguides for Mid-IR supercontinuum generation,"
    Opt. Express 23, 17345-17354 (2015)
  4. Darren D. Hudson, Matthias Baudisch, Daniel Werdehausen, Benjamin J. Eggleton, and Jens Biegert,
    "1.9 octave supercontinuum generation in a As2S3 step-index fiber driven by mid-IR OPCPA,"
    Opt. Lett. 39, 5752-5755 (2014)
  5. Fangxin Li, Stuart D. Jackson, Christian Grillet, Eric Magi, Darren D. Hudson, Steven J. Madden, Yashodhan Moghe, Christopher O’Brien, Andrew Read, Steven G. Duvall, Peter Atanackovic, Benjamin J. Eggleton, and David J. Moss, "Low propagation loss silicon-on-sapphire waveguides for the mid-infrared," Opt. Express 19, 15212-15220 (2011).
  6. Darren D. Hudson, Stephen A. Dekker, Eric C. Mägi, Alexander C. Judge, Stuart D. Jackson, Enbang Li, J. S. Sanghera, L. B. Shaw, I. D. Aggarwal, and Benjamin J. Eggleton, "Octave spanning supercontinuum in an As2S3taper using ultralow pump pulse energy," Opt. Lett. 36, 1122-1124 (2011).
  7. Darren D. Hudson, Eric C Magi, L. Gomes, and Stuart D. Jackson, “1 W diode-pumped tunable Ho3+, Pr3+-doped fluoride glass fibre laser,” Electron. Lett. 47, 985 (2011).