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Research

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Novel Photonic Materials and Fabrication

Shaping novel nanophotonic materials

Silicon Photonics

Enabling the next generation of computing systems

Nano-Electromagnetism

Manipulating waves at the nanoscale

Sensing and Optofluidics

Sensing and manipulating biological analytes

Optomechanics

Controlling the interaction between phonons and photons

Nonlinear and Quantum Optics
Nonlinear Optics

Generating extreme nonlinearities in nanophotonic structures

Nonlinear and Quantum Optics

Published papers (partial list)

 

On-Chip Nonlinear Optics

Normally, photonic devices are linear systems: When you input one frequency of light, you get out the same frequency, and only that frequency.  However, at high enough light intensities, photons can interact with the material and each other to generate new frequencies of light.  These nonlinear processes are usually observed with extremely high power free-space laser pulses, but with the advent of integrated photonics, we can efficiently generate new frequencies with moderately low power levels on chip (<100mW).  This is because the high index contrast of the waveguides confines the light to a very small area for a long distance, yielding very high intensities and long interaction lengths.  In addition, the high finesse of on-chip cavities further enhances the intensity within the resonator.  These qualities make on-chip devices ideal for nonlinear optics.  

On-chip integration of nonlinear optics enables a high performance and compact platform for frequency conversion for a variety of applications.  In collaboration with the Gaeta group at Cornell, we have demonstrated numerous nonlinear optical processes, including frequency comb generation in silicon nitride and silicon micro-resonators, second-harmonic generation, and CW wavelength conversion.  Using an integrated platform, we can take advantage of the strong nonlinearity of semiconductor thin films to achieve miniaturized (<200 um) nonlinear optical devices. Silicon nitride is our main platform for telecom frequency conversion and frequency comb generation.  Taking advantage of silicon nitride's high third order nonlinearity, and low linear and nonlinear losses, we have shown an octave spanning frequency comb in the telecom wavelength range (around 1550nm).  In addition we have shown comb generation towards visible wavelengths, either directly by pumping at 1064nm, or indirectly by generating and converting a telecom comb within the same resonator.  

Contact: Kevin Luke, Steven Miller

Levy, J. S. et al. CMOS-compatible multiple-wavelength oscillator for on-chip optical interconnects. Nature Photonics 4, 37-40 (2010) <http://dx.doi.org.10.1038/nphoton.209.259>

Luke, K., Dutt A., Poitras, C. B., and Lipson, M. Overcoming Si3N4 film stress limitations for high quality factor ring resonators. Opt. Express 21, 22829-22833(2013). <http://dx.doi.org/10/1364/OE.21.022829>

Levy, J. S., Foster, M. A., Gaeta, A. L. and Lipson, M., Harmonic generation in silicon nitride ring resonator, Opt. Express 19, 11415, 06 June 2011. http://dxdoi.org/10.1365/OE.19.011415

Silicon in one of the most ideal platforms for mid-IR nonlinear optics, due to silicon's wide transparency window and high nonlinearity.  The mid-IR spectral region is of particular interest, as there is a plethora of molecular gas absorption lines there.  We recently demonstrated the first realization of an on-chip integrated frequency comb source in a silicon resonator, and the first on-chip integrated mid-IR frequency comb.  We were able to achieve parametric comb generation past 3 um, enabling mid-IR gas detection in that spectral range.

Contact Austin G. Griffith

Griffith, A.G., et al., Sillicon-chip mid-infrared frequency comb generation. CLEO: 2014 Postdeadline Paper Digest, 1(C), STh5C.6 <http://doi:10.1364/CLEO_SI.2014.STh5C.6>

We are also interested in on-chip temporal imaging application and have demonstrated such a system that is based on parametric mixing.  With this system, we demonstrated, in collaboration with the Gaeta group at Cornell, the ability to characterize temporal waveforms with 1.4 ps resolution and 530 ps record length. On-chip ultra-fast oscilloscopes and time lenses were demonstrated.

On-chip Quantum Optics

Quantum optics exploits the non-classical behavior of light for application such as quantum-enhanced sensing, spectroscopy, metrology and quantum information processing.  Most conventional quantum optics experiments rely on table-top optical setups which are bulky and not scalable.  We work on realizing these experiments on a photonic ship, which makes them compact, robust, stable and most importantly, scalable.  The compactness of the devices also enable the generation of quantum correlations over large bandwidths, which is essential for high speed quantum communication and quantum computing.

We have demonstrated on-chip generation of squeezed states of light, i.e. light with ultra-low noise level in one quadrature, below the standard quantum limit (SQL). Such states of light possess quantum correlations which can be approaching the SQL between different longitudinal modes of optical frequency comb based on a chip-scale optical parametric oscillator.  Silicon nitride waveguides and resonators are the primary devices we use for the generation and manipulation of quantum states of light. 

Contact Avik Dutt, Aseema Mohanty

Dutt, A., et. al., On-chip optical squeezing, arXiv:1309.6371 (2013) http://arxiv.org/abs/1309.6371

 

This shows a top view visible CCD camera image of the microresonator generating second harmonic red light. IR light, invisible to this camera, is launched from the left and couples into the ring. The power builds-up in the ring generating SH which couples back into the waveguide propagating out to the right.

Experimental measurement of generated mid-IR generated sicganls. The graph shows the four-wave mixing spectrum of idler wavelength generated at 2384 nm using a pump wavelength at 1940 nm and a signal wavelength at 1636 nm.

Schematic of the ultrafast time-lens based oscilloscope scheme, which uses time-to-space conversion.


Recent News

Prof. Lipson ranked among top 1% of researchers for most cited papers in physics

Prof. Lipson ranked among top 1% of researchers for most cited papers in physics by Thomas Reuters.