We give instructions for the construction and operation of a simple apparatus for performing optically detected magnetic resonance measurements on diamond samples containing high concentrations of nitrogen-vacancy (NV) centers. Each NV center has a spin degree of freedom that can be manipulated and monitored by a combination of visible and microwave radiation. We observe Zeeman shifts in the presence of small external magnetic fields and describe a simple method to optically measure magnetic field strengths with a spatial resolution of several microns. The activities described are suitable for use in an advanced undergraduate lab course, powerfully connecting core quantum concepts to cutting edge applications. An even simpler setup, appropriate for use in more introductory settings, is also presented.

1.
B. L.
Donnally
and
E.
Bernal
, “
Some experiments on nuclear magnetic resonance
,”
Am. J. Phys.
31
,
779
784
(
1963
).
2.
Developing next generation electronic devices based on quantum materials is the mission of the National Science Foundation supported Center for Integrated Quantum Materials (CIQM), which is supporting the work described here. See ciqm.harvard.edu for more information.
3.
This is the specification for the Bruker 500 MHz NMR spectrometer that is the workhouse used in organic chemistry labs at Wellesley College.
4.
A.
Gruber
,
A.
Drabenstedt
,
C.
Tietz
,
L.
Fleury
,
J.
Wrachtrup
, and
C.
von Borczyskowski
, “
Scanning confocal optical microscopy and magnetic resonance on single defect centers
,”
Science
276
,
2012
2014
(
1997
).
5.
R.
Hanson
,
L.
Kouwenhoven
,
J.
Petta
,
S.
Tarucha
, and
L.
Vandersypen
, “
Spins in few-electron quantum dots
,”
Rev. Mod. Phys.
79
,
1217
2065
(
2007
).
6.
L. I.
Childress
, “
Coherent manipulation of single quantum systems in the solid state
,” Ph.D. thesis, Harvard University Cambridge, Massachusetts (
2007
).
7.
L.
Childress
,
R.
Walsworth
, and
M.
Lukin
, “
Atom-like crystal defects: From quantum computers to biological sensors
,”
Phys. Today
67
(
10
),
38
43
(
2014
).
8.
T. D.
Ladd
,
F.
Jelezko
,
R.
Laflamme
,
Y.
Nakamura
,
C.
Monroe
, and
J. L.
O'Brien
, “
Quantum computers
,”
Nature
464
,
45
53
(
2010
).
9.
Y.
Doi
,
T.
Makino
,
H.
Kato
,
D.
Takeuchi
,
M.
Ogura
,
H.
Okushi
,
H.
Morishita
,
T.
Tashima
,
S.
Miwa
,
S.
Yamasaki
 et al, “
Deterministic electrical charge-state initialization of single nitrogen-vacancy center in diamond
,”
Phys. Rev. X
4
,
011057
(
2014
).
10.
J.
Maze
,
P.
Stanwix
,
J.
Hodges
,
S.
Hong
,
J.
Taylor
,
P.
Cappellaro
,
L.
Jiang
,
M. G.
Dutt
,
E.
Togan
,
A.
Zibrov
,
A.
Yacoby
,
R. L.
Walsworth
, and
M. D.
Lukin
, “
Nanoscale magnetic sensing with an individual electronic spin in diamond
,”
Nature
455
,
644
647
(
2008
).
11.
G.
Balasubramanian
,
I.
Chan
,
R.
Kolesov
,
M.
Al-Hmoud
,
J.
Tisler
,
C.
Shin
,
C.
Kim
,
A.
Wojcik
,
P. R.
Hemmer
,
A.
Krueger
 et al, “
Nanoscale imaging magnetometry with diamond spins under ambient conditions
,”
Nature
455
,
648
651
(
2008
).
12.
R.
Schirhagl
,
K.
Chang
,
M.
Loretz
, and
C. L.
Degen
, “
Nitrogen-vacancy centers in diamond: Nanoscale sensors for physics and biology
,”
Annu. Rev. Phys. Chem.
65
,
83
105
(
2014
).
13.
O.
Patange
, “
On an instrument for the coherent investigation of nitrogen-vacancy centres in diamond
,” Master's thesis, University of Waterloo, Waterloo (
2013
).
14.
I. L.
Markov
, “
Limits on fundamental limits to computation
,”
Nature
512
,
147
154
(
2014
).
15.

Other examples of quantum materials include single atomic layer materials such as graphene (Ref. 29) which could enable ultrafast signal processing, and topological insulators (Ref. 30) which may lead to error-free channels for transporting spin information. Developing next generation electronic devices based on quantum materials is the mission of the National Science Foundation supported Center for Integrated Quantum Materials (CIQM), which is supporting the work described here. See <ciqm.harvard.edu> for more information.

16.
M.
Resnick
,
R.
Berg
, and
M.
Eisenberg
, “
Beyond black boxes: Bringing transparency and aesthetics back to scientific investigation
,”
J. Learn. Sci.
9(1)
,
7
30
(
2000
).
17.

A number of factors are responsible for the weakness of the interaction of the spin with its surroundings. For example, because the 12C nucleus has a spin of zero, the “spin-spin” interactions are small. Also, the low mass and stiff interatomic bonds of the carbon lattice lead to a high Einstein temperature (TE=2300K), which makes the interaction of the NV center) with the vibrational modes of the surrounding lattice unusually weak at room temperature.

18.
J.
Wrachtrup
and
F.
Jelezko
, “
Processing quantum information in diamond
,”
J. Phys. Condens. Matter
18
,
S807
S824
(
2006
).
19.

Equation (2) is only valid in the limit that the magnetic field strength is much smaller than the zero-field splitting between the ms = 0 state and the ms=±1 states; i.e., when B||2.87GHz/γ. This condition is satisfied for all the experiments described here.

20.
M. W.
Doherty
,
N. B.
Manson
,
P.
Delaney
,
F.
Jelezko
,
J.
Wrachtrup
, and
L. C.
Hollenberg
, “
The nitrogen-vacancy colour centre in diamond
,”
Phys. Rep.
528
(
1
),
1
45
(
2013
).
21.

Element Six sells HPHT diamond with suitably high nitrogen concentrations. See Ref. 31 for more detailed guidance on creating high NV concentrations in such samples via electron irradiation and annealing.

22.
V.
Acosta
,
E.
Bauch
,
M.
Ledbetter
,
A.
Waxman
,
L.-S.
Bouchard
, and
D.
Budker
, “
Temperature dependence of the nitrogen-vacancy magnetic resonance in diamond
,”
Phys. Rev. Lett.
104
,
070801
(
2010
).
23.
V. M.
Acosta
, “
Optical magnetometry with nitrogen-vacancy centers in diamond
,” Ph.D. thesis, University of California, Berkeley (
2011
).
24.
D. R.
Glenn
,
K.
Lee
,
H.
Park
,
R.
Weissleder
,
A.
Yacoby
,
M. D.
Lukin
,
H.
Lee
,
R. L.
Walsworth
, and
C. B.
Connolly
, “
Single cell magnetic imaging using a quantum diamond microscope
,”
Nat. Methods
12
,
736
738
(
2015
).
25.
G.
Kucsko
,
P.
Maurer
,
N.
Yao
,
M.
Kubo
,
H.
Noh
,
P.
Lo
,
H.
Park
, and
M.
Lukin
, “
Nanometre-scale thermometry in a living cell
,”
Nature
500
,
54
58
(
2013
).
26.
D. Le
Sage
,
K.
Arai
,
D.
Glenn
,
S.
DeVience
,
L.
Pham
,
L.
Rahn-Lee
,
M.
Lukin
,
A.
Yacoby
,
A.
Komeili
, and
R.
Walsworth
, “
Optical magnetic imaging of living cells
,”
Nature
496
,
486
489
(
2013
).
27.
Excellent lower cost alternative laser systems are the Coherent Compass 215M or the Laserglow Technolgies LCS-532 series. There are even less expensive 532 nm lasers, but these are typically not temperature stabilized. This results in significant fluctuations in output power that may obscure the relatively small variations in fluorescence intensity that we observe here. To reduce the detrimental effects of power fluctuations it helps to record the spectra quickly. Also, for the laser intensities used here, the fluorescence is linearly proportional to the laser power and for longer scans we have had good success in minimizing the effect of laser power fluctuations by monitoring the laser power and normalizing.
28.
J.
Tisler
,
G.
Balasubramanian
,
B.
Naydenov
,
R.
Kolesov
,
B.
Grotz
,
R.
Reuter
,
J.-P.
Boudou
,
P. A.
Curmi
,
M.
Sennour
,
A.
Thorel
, et al, “
Fluorescence and spin properties of defects in single digit nanodiamonds
,”
ACS Nano
3
,
1959
1965
(
2009
).
29.
A.
Geim
and
I.
Grigorieva
, “
Van der Waals heterostructures
,”
Nature
499
,
419
425
(
2013
).
30.
J. E.
Moore
, “
The birth of topological insulators
,”
Nature
464
,
194
198
(
2010
).
31.
D.
Farfurnik
,
N.
Alfasi
,
S.
Masis
,
Y.
Kauffmann
,
E.
Farchi
,
Y.
Romach
,
Y.
Hovav
,
E.
Buks
, and
N.
Bar-Gill
, “
Enhanced concentrations of nitrogen-vacancy centers in diamond through TEM irradiation
,”
Appl. Phys. Lett.
111
(
12
),
123101
(
2017
).
32.
This write-up tends to evolve over time as we discover ways in which the lab can be improved. For the latest version please contact the corresponding author at rberg@wellesley.edu.
33.
See Supplementary Material at https://doi.org/10.1119/1.5023389 for the Spring, 2018 version of the lab write-up.

Supplementary Material

AAPT members receive access to the American Journal of Physics and The Physics Teacher as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.