1. Optical levitation of high purity nanodiamonds in vacuum
Gavin W Morley, University of Warwick

2. Acknowledgments Warwick University Angelo Frangeskou
Anis Rahman (now UCL)
Colin Stephen
Guy Stimpson
Yashna Lekhai
University College London
Peter Barker
Sougato Bose
Imperial College London
Myungshik Kim
Chuanqi Wan
Cardiff University
Laia Gines, Soumen Mandal, Oliver Williams

6. Outline Why diamond? Our results
- Optically trapped diamonds heat up to destruction at 5 mbar
- Pure nanodiamonds don’t heat up at 4 mbar

7. Nitrogen vacancy (NV-) centres in diamond
1. Introduction: why diamond?
Nitrogen vacancy (NV-) centres in diamond
Nitrogen
Vacancy
637 nm
Review: MW Doherty et al, Phys Rep 528, 1 (2013)

8. Nitrogen-vacancy centres without levitation
1. Introduction: why diamond?
Nitrogen-vacancy centres without levitation

9. Nitrogen-vacancy (NV-)
1. Introduction: why diamond?
Nitrogen-vacancy (NV-)
Green excitation
 Spin polarization
 Spin readout

10. Levitating nanodiamonds in air
1. Introduction: why diamond?
Levitating nanodiamonds in air
- Berlin: atmospheric pressure,
A Kuhlicke, AW Schell, J Zoll & O Benson, APL 105, (2014)
- Paris: 10-2 mbar,
T Delord, L Nicolas, L Schwab & G Hétet, NJP 19, (2017) + others
ICFO, Barcelona: 0.5 mbar,
G P Conangla, A W Schell, R A Rica & R Quidant, arXiv:
- University College London: Peter Barker‘s group
- Pittsburgh: 6.7 x 10-3 mbar,
J-F Hsu, P Ji, CW Lewandowski & B D’Urso, Sci Rep 6, (2016)
- Rochester: 1064 nm, >5 mbar,
LP Neukirch, E von Haartman, JM Rosenholm & AN Vamivakas,
Nat Photon 9, 653 (2015) + others
- Purdue: 1550 nm, >10 mbar
TM Hoang, J Ahn, J Bang & T Li, Nat Comms 7, (2016) + others
Ion traps
Magneto-gravitational trap
Optical traps

11. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)
From other groups:
- Z-q Yin, T Li, X Zhang & LM Duan,
PRA 88, (2013)

12. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)

13. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)

14. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)

15. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)

16. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)

17. drop a nanodiamond containing a spin
1. Introduction: why diamond? 2. Our work
Our proposal:
drop a nanodiamond containing a spin
From our collaboration:
- M Scala et al., PRL 111, (2013)
- C Wan et al., PRA 93, (2016)
- C Wan et al., PRL 117, (2016)
- S Bose et al., PRL 119, (2017)

18. Spatial superposition needs high vacuum
1. Introduction: why diamond? 2. Our work
Spatial superposition needs high vacuum

19. 1. Introduction: why diamond? 2. Our work
Our levitating nanodiamonds: optical trap with 40 nm diamonds and 1064 nm

20. Analytical model for interferometric balanced detection
1. Introduction: why diamond? 2. Our work
Analytical model for interferometric balanced detection
ATM Anishur Rahman, AC Frangeskou, PF Barker & GW Morley, Review of Scientific Instruments 89, (2018)

21. Analytical model for interferometric balanced detection
1. Introduction: why diamond? 2. Our work
Analytical model for interferometric balanced detection
ATM Anishur Rahman, AC Frangeskou, PF Barker & GW Morley, Review of Scientific Instruments 89, (2018)

22. Background: Brownian thermometry
J Millen, T Deesuwan, P Barker & J Anders, Nature Nanotechnology 9, 425 (2014)
ATM Anishur Rahman, AC Frangeskou, PF Barker & GW Morley, Review of Scientific Instruments 89, (2018)

23. Levitating nanodiamonds overheating
1. Introduction: why diamond? 2. Our work
Levitating nanodiamonds overheating
20 mbar
ATMA Rahman et al., Scientific Reports 6, (2016)

24. A solution: more pure diamonds
1. Introduction: why diamond? 2. Our work
A solution: more pure diamonds
150 ppm nitrogen ppb nitrogen
impurities impurities
AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, New Journal of Physics 20, (2018)

25. A solution: more pure nanodiamonds
1. Introduction: why diamond? 2. Our work
A solution: more pure nanodiamonds
150 ppm nitrogen ppb nitrogen
impurities
Milling by Ollie Williams’ group, Cardiff
AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, New Journal of Physics 20, (2018)

26. A solution: more pure nanodiamonds
1. Introduction: why diamond? 2. Our work
A solution: more pure nanodiamonds
4 mbar
AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, New Journal of Physics 20, (2018)

27. Conclusion: Purer diamonds don’t heat up at 4 mbar
AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, New Journal of Physics 20, (2018)

28. Conclusion: Outlook: Purer diamonds don’t heat up at 4 mbar
AC Frangeskou, ATMA Rahman, L Gines, S Mandal, OA Williams, PF Barker & GW Morley, New Journal of Physics 20, (2018)

29. Outlook: