Birck Nanotechnology Center

ECE 695 Lecture on Nanolasers Presented by Mawufemor “Yao” Kudadze and Clayton DeVault

December 2, 2013 1

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December 2, 2013 2

HONEY, I SHRUNK THE LASER!

http://www.aip.org/history/exhibits/laser/sections/therace.html

Ted Maiman, May 1960

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LASER: An Optical Oscillator

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An amplifier with a gain-saturation mechanism

A feedback system A frequency-selection

mechanism An output coupling scheme

An oscillator comprises,

Fundamentals of Photonics, B.E.A. Saleh and M.C. Teich, John Wiley and Sons (2007)

Sub-wavelength dimensions!

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Why do we need a Nanolaser?

December 2, 2013 4

Moore’s law in photonics

M.K. Smith, Moore’s Law in photonics, Laser and Photonics Rev. Vol. 6, 1-13, (2012)

Bottle-neck for down scaling photonic circuits remains the lack of an integrated and efficient light source on a chip!

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Why do we need a Nanolaser?

December 2, 2013 5 M.K. Smith, Moore’s Law in photonics, Laser and Photonics Rev. Vol. 6, 1-13, (2012)

Other areas of application

• Optical Metrology

• Sensing, particularly applied in the bio-medical and chemical fields

• Ultra-fast spectroscopy

• Plus, its just cool!

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Challenges for Nanolasers

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Surface Plasmon Amplification by Stimulated Emission of Radiation: Quantum Generation of Coherent Surface Plamons in Nanosystems

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“The spaser radiation consists of SPs that are bosons and undergo stimulated emission but in contrast to photonics can be localized on the nanoscale.”

“A spaser is the nanoplasmonic counterpart of a laser, but it (ideally) does not emit photons.”

M.I. Stockman, Nature Photonics 2, 237-329 (2008)

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Single-interface SPPs: incorporating gain

December 2, 2013 8 P. Berini and I.D. Leon, Nature Photonics 6, 16-24 (2012)

J. Seidel et al. Phys. Rev. Lett. 94, 177401 (2005)

P.M. Bolger et al. Opt. Lett. 35, 1197 (2010)

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The race for a nanolaser

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Appl. Phys. Lett. 91, 181112 (2007)

Nature Materials 1, 106 - 110 (2002)

PHYSICAL REVIEW A 74, 051802R 2006

Opt. Express 14, 1094-1105 (2006)

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Demonstration of a spaser-based nanolaser M.A. Noginov et. al., Norfolk State University

Spaser design

Emission kinetics Stimulated emission

M.A. Noginov, V.M. Shalaev, U. Wiesner et. al. Nature 000, 1-3 (2009)

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Multiple cavity mode resonances => sufficient material gain for full laser oscillation => nonlinear response Weak dependence of plasmonic cavity modes on diameter and no photonic modes with small diameter cavities

Plasmon Laser at deep subwavelength scale X. Zhang et. al., U.C. Berkeley

X. Zhang et. al. Nature 461, 629 (2009)

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High field loss with MIM But allows sub-wavelength confinement TM only with small t and Supports TE mode for large t

Electrically pumped MIM structure - Gain incorporated for loss Compensation

Lasing in metal-insulator-metal (MIM) sub-wavelength plasmonic waveguides M.T. Hill, COBRA research institute

M.T. Hill Opt. Express 17, 11107 (2009)

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Lasing in metal-insulator-metal (MIM) sub-wavelength plasmonic waveguides M.T. Hill, COBRA research institute

M.T. Hill Opt. Express 17, 11107 (2009)

I<It

I>It

78K

I<It I>It

I>It

I<It

10K

Theoretical Q > 140 @ 300K Measure Q = 370 @ 78K 340 @ 300K

298K

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Strong couling with higher momentum and minimized metal loss Strong Confinement with Q~100 => High Purcell factor of 18 => low lifetime (emission rate enhancement)

Room-temperature sub-diffraction-limited plasmon laser by total internal reflection X. Zhang, U.C. Berkeley

X. Zhang, Nature Materials 10, 110 (2011)

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Plasmonic Bowtie Nanolaser Arrays T.W. Odom et. al., Northwestern University

Teri W. Odom; Nano Lett. 2012, 12, 5769-5774.

Bowtie Lasing at Room Temperature

Bi-periodic array for periods of 1.2µm and 0.6µm

Optical Characterization

NANO LETTERS

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Optically pumped room-temperature GaAs nanowire lasers

C. Jagadish et. al., Australian National Unviersity

C. Jagadish et al. Nature Photonics 7, 1-6 (2013)

nature photonics

Low-temperature Lasing Characterisitics From left to right, core GaAs,

core-shell AlGaAs,GaAs, core-shell-cap GaAs/AlGaAs/GaAs Nanolase (500nm scale bar)

Room-temperature Lasing Characteristics in Near-IR

Optimize threshold gain using, where is the mode confinement factor, gth is threshold gain and L and R are the length and radius of the nanowire, respectively.

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Conclusion Perspective and challenges

X. Meng et al. Nano Letters 13, 4106 (2013)

Success with material for miniaturization , loss- compensation and amplifying (Plasmons), Operating temperatures (Room) Large momentum mismatch of light inside and outside of a nano- sized

cavity yielding beam diffraction into all directions at exit of cavity.

High optical pumping damage - Realistic applications require innovative design structures for electrical pumping without perturbation of the optical mode.

For large scale integration, top-down processing is preferred, yet most current plasmon laser have relied on bottom up semiconductor growth techniques and post growth assembly.

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Thank you for your attention!

Question?