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TF Krauss, WavePro No.1/32

Thomas F Krauss

University of St. Andrews, School of Physics and Astronomy, St. Andrews, UK

Light generation and control in SOI Photonic crystals

Liam O'Faolain, Abdul Shakoor, Karl Welna

Christelle Monat, Bill Corcoran, Ben Eggleton, CUDOS

Matteo Galli, Dario Gerace, Simone Portalupi, Lucio Claudio Andreani, Pavia

Francesco Priolo, Giorgia Franzo, Catania

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TF Krauss, WavePro No.2/32

How grey silicon can help you generate new colours

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TF Krauss, WavePro No.3/32

1. SOI Photonic crystals

220 nm Si waveguide, airbridge or oxide clad

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TF Krauss, WavePro No.4/32

Mechanism!

a!

In the slow light regime, one can imagine the mode taking a longer route - that’s why it takes more time, and why there is more light inside the structure. !

Cavities can be understood as waveguides with their ends plugged up.!

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TF Krauss, WavePro No.5/32

Nonlinear wavelength conversion

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TF Krauss, WavePro No.6/32

Third harmonic generation

!

I" =P"A#ngneff C. Monat et al., Nature Photonics, April 2009

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TF Krauss, WavePro No.7/32

Signal/Noise Monitoring - Concept

B. Corcoran et al., “Optical signal processing on a silicon chip at 640Gb/s using slow-light”, Optics Express 18, 7770 (2010)

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TF Krauss, WavePro No.8/32

Bandwidth

640 Gbit/s -> 500fs pulses

B. Corcoran et al., “Optical signal processing on a silicon chip at 640Gb/s using slow-light”, Optics Express 18, 7770 (2010)

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TF Krauss, WavePro No.9/32

2. New colours from cavities

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TF Krauss, WavePro No.10/32

High Q (low loss) comes from lack of radiation within escape cone/ light cone.

High Q cavity

Real space

Fourier space

S. Noda et al., Nature 425, p.944 (2003)

Light cone

Q!45 k

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TF Krauss, WavePro No.11/32

High Q (low loss) comes from lack of radiation within the light cone.

But where does the cavity emission actually go ?

k 0

Farfield

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TF Krauss, WavePro No.12/32

Solution: Secondary grating

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TF Krauss, WavePro No.13/32

Solution: Secondary grating

S. L. Portalupi et al., Optics Express July 2010

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TF Krauss, WavePro No.14/32

!/a!

"

k-!/a!

2!/a!

2!/2a!

a 2a !/a!

Solution: Secondary grating

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TF Krauss, WavePro No.15/32

S. L. Portalupi et al., Optics Express July 2010

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TF Krauss, WavePro No.16/32

M Galli et al. Optics Express, December 2010

Nonlinear effects (here: Second and third harmonic generation) observed due to high intensity buildup and far-field engineering

Harmonic Generation

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TF Krauss, WavePro No.17/32

Ex Nearfield

Model Farfield Experiment Farfield

SHG –surface effect

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TF Krauss, WavePro No.18/32

Ey Nearfield

Model Farfield Experiment Farfield

THG – bulk effect

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TF Krauss, WavePro No.19/32

THG and SHG in Si cavities

M Galli et al. Optics Express, December 2010

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TF Krauss, WavePro No.20/32

Output power

M Galli et al. Optics Express, December 2010

Output power is “absolutely useless for photonics” (Referee NPhot)

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TF Krauss, WavePro No.21/32

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TF Krauss, WavePro No.22/32

! 100 "W

THG emission vs. Nanolaser

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TF Krauss, WavePro No.23/32

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TF Krauss, WavePro No.24/32

3. Silicon (linear) light emission ?

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TF Krauss, WavePro No.25/32

Nature Materials 2005

Bandedge “A-Centre”

“A-type trapping centres….attributed to silicon vacancies” (10K)

“A-Centre”

Defect emission from “A” Centres

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TF Krauss, WavePro No.26/32

“Room-temperature emission at telecom wavelengths from silicon photonic crystal nanocavities” R. Lo Savio et al., accepted for publication in Appl. Phys. Lett.

Defect emission from Hydrogen implants

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TF Krauss, WavePro No.27/32

Nature News & Views, 1997

!

fP =3"3

4# 2QV

!rad =" nonrad

" rad +" nonrad

E. M. Purcell, Phys. Rev. 69, 37 (1946).

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TF Krauss, WavePro No.28/32

!rad =" nonrad

" rad +" nonrad

The Purcell-factor makes defect emission “Room-temperatureable”

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TF Krauss, WavePro No.29/32

Bulk defects (SOITEC process)

Surface defects (Plasma process)

Further improvements ?

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TF Krauss, WavePro No.30/32

!

!

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TF Krauss, WavePro No.31/32

!

1 pW 3000 x SOI

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TF Krauss, WavePro No.32/32

Conclusion