Download Single-photon sources based on NV

Single-photon NV sources
Pauli Kehayias
March 16, 2011
March 16, 2011
Pauli Kehayias
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Outline
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Quantum nature of light
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Photon correlation functions
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Single-photon sources
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NV diamond single-photon sources
March 16, 2011
Pauli Kehayias
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Wave/particle duality
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Light exhibits wave and particle properties
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Wave: oscillating E & B fields
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Double slit experiment, dipole radiation
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Particle: quantized energy (E = hν)
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Photoelectric effect
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Pauli Kehayias
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Quantum light
1
1 2 3
2

E

∫ 0 0 B d r
2
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H EM =
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After a lot of math,
H EM =∑ ℏ  k a k , s a k , s
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This is like a SHO:
[a k , s a†k ' , s ' ]= k , k '  s , s ' , a†k ,s a k , s =n k , s
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nk , s
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a †k , s
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k ,s

†


1
1
= ∑ ℏ  k nk , s 
2
2
k ,s

is the photon number
& a are photon creation & destruction
operators
k ,s
Eigenstates are
March 16, 2011
| nk , s >
for each mode/polarization
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Coherence of light
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Given a phase at time t, how well can we
predict the phase at t + τ ?
Light sources emit pulse trains, with phase
discontinuities between them
A typical time between discontinuities can be
thought of as the coherence time
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An example
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Young's double slit
experiment
Consider Imax – Imin
Screen
Slits
Source
Largest when
perfectly coherent
Smallest when
incoherent
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A classical coherence function
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A classical coherence function
〈 E * t  E t〉
 =
 〈∣E t ∣2 〉 〈∣E t∣2 〉
1 
Is proportional to fringe visibility and
interference term
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Magnitude ranges from 0 to 1
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For coherence time τ0,
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We can also define a quantum version g(1)(τ)
March 16, 2011
1  =1−
Pauli Kehayias

0
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Second order coherence
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Hanbury-Brown and
Twiss experiment
Beam splitter
Coincident count rate
~ 〈 I t  I t 〉
 2
 =
Detector
〈 I t  I t 〉
〈 I t 〉 〈 I t 〉
For number states,
for n = 0,1
g 0=0
1
g 0=1−
otherwise
n
 2
τ
Coinc.
Time delay
 2
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Uses for single-photon states
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Quantum optics experiments (Hanbury-Brown
and Twiss, Mach-Zehnder, Pfleegor-Mandel)
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Quantum key distribution [2,3]
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Quantum computing
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Single-photon sources
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Attenuated lasers
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Atoms and molecules
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Quantum dots
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NV diamond centers
[4]
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Single-photon NV diamond
realizations
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Things to consider: excitation efficiency,
collection efficiency, manufacturing difficulty
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Extract photons without any help [4]
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Attach a separate waveguide or cavity
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Make diamond nanostructures with embedded
NV centers
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Bulk diamond + waveguide
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Attach a GaP layer on top of a bulk diamond
as the waveguide (2.26 eV bandgap, n = 3.3)
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Achieved for many NV centers
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Easy to make, but is lossy
[5]
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Diamond nanoparticle + cavity
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High-Q microsphere resonators
Hard to position microsphere and diamond
pillar close together
[6]
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Diamond nanowires (1)
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Etch diamond pillars onto bulk diamond (ebeam lithography & reactive-ion etching)
[7]
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Diamond nanowires (2)
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Advantage: better excitation and collection
efficiency
Disadvantages: hard to manufacture
[8]
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Commercial realization
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Diamond grown on an optical fiber
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Runs at room temperature
[9]
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References
1. C. Gerry, P. Knight, “Introductory Quantum Optics”, Cambridge University Press (2004).
2. G. Greenstein, A. G. Zajonc, “The Quantum Challenge: Modern Research on the Foundations of Quantum
Mechanics” 2nd ed., Jones and Bartlett (2006).
3. A. Beveratos et al., “Single photon quantum cryptography”, PRL 89, 187901 (2002).
4. R. Brouri et al., “Photon antibunching in the fluorescence of individual color centers in diamond”, Optics
Letters, Vol. 25, Issue 17 (2000).
5. K.-M. C. Fu et al., “Coupling of nitrogen-vacancy centers in diamond to a GaP waveguide”, Appl. Phys.
Lett. 93, 234107 (2008).
6. M. Larsson et al., “Composite Optical Microcavity of Diamond Nanopillar and Silica Microsphere”, Nano
Lett. 9 4 (2009).
7. T. Babinec et al., “A diamond nanowire single-photon source”, Nature Nanotechnology 5 (2010) .
8. B. J. M. Hausmann et al., “Fabrication of Diamond Nanowires for Quantum Information Processing
Applications”, Diamond and Related Materials 19 (2010).
9. Quantum Communications Victoria (QCV), <http://qcvictoria.com/>
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