Slow and Stored Light

OSA Latvian Student Chapter

Linards Kalvans

Riga, November 12, 2007

November 12, 2007 Slow and Stored Light, Linards Kalvans 2

Malēnieši uztaisīja namu, bet aizmirsa ierīkot logus. Tādēļ gaismu namā nesa ar maisiem iekšā.

November 12, 2007 Slow and Stored Light, Linards Kalvans 3

Outline

• Introduction

• Slowing down the light

• Storing the light

• Possible applications and future research

November 12, 2007 Slow and Stored Light, Linards Kalvans 4

Phase and group velocities

• Phase velocity:

n

cv v – phase velocity

c – velocity of light in vacuumn – light refraction index in a given medium

• Group velocity:1

d

dnncvg

vg – group velocity – wavelength of lightdn/d – light dispersion in a given medium

November 12, 2007 Slow and Stored Light, Linards Kalvans 5

Slowing Down the LightEIT – Electromagnetically Induced Transparency

• A three level lambda system

1

d

dnncvg

• Pumping field splits the |e> state making the medium transparent to the probe

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Slowing Down the Light

22 /1

Ng

cvg

• Limitations:

NkLgEIT 2

2

g – atom-field coupling coefficient;N – number of atoms; – Rabi frequency; – relaxation rate of optical coherences;k – the wave vector;L – the atomic vapor cell length;

Delay and transmission of pulse as a function of control field power; The active medium is Rb vapor in near room temperature buffered with 5 torr of Ne. I. Novikova, M. Klein, D.F. Phillips and R.L. Walsworth; Proceedings of SPIE 5735, 87-97 (2005)

November 12, 2007 Slow and Stored Light, Linards Kalvans 7

Storing the Slowed Light

• The long (several km) light impulse is compressed to few m;

• The energy is transfered back and forth from the coupling to the probe field via atomic states;

• If the coupling field is turned off the light is “stored” entirely in the atomic states.

The Story Behind Stopped Light. R. Walsworth, S. Yelin, and M. Lukin, Optics and Photonics News 13(5), 50 (May, 2002).

November 12, 2007 Slow and Stored Light, Linards Kalvans 8

Experimental results

I. Novikova, M. Klein, D.F. Phillips and R.L. Walsworth; Proceedings of SPIE 5735, 87-97 (2005) Optimization of slow and stored light in atomic vapor. I. Novikova, A.V. Gorshkov, D.F. Phillips, Y. Xiao, M. Klein and R.L. Walsworth Proceedings of SPIE 6482, 64820M1-64820M11 (2007)

November 12, 2007 Slow and Stored Light, Linards Kalvans 9

Direct View of the Compressed Pulse

The art of taming light: ultra-slow and stopped light, Zachary Dutton, Naomi S. Ginsberg, Christopher Slowe, and Lene Vestergaard Hau, Europhysics News (2004) Vol. 35 No. 2

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Manipulating the Stored Light

The Story Behind Stopped Light. R. Walsworth, S. Yelin, and M. Lukin, Optics and Photonics News 13(5), 50 (May, 2002).

November 12, 2007 Slow and Stored Light, Linards Kalvans 11

Dark State Solitons – Test of BEC Superfluidity

The art of taming light: ultra-slow and stopped light, Zachary Dutton, Naomi S. Ginsberg, Christopher Slowe, and Lene Vestergaard Hau, Europhysics News (2004) Vol. 35 No. 2

November 12, 2007 Slow and Stored Light, Linards Kalvans 12

References

• Web page of Roland Walsworth’s grouphttp://cfa-www.harvard.edu/Walsworth/

• Web page of Lene Vestergaard Hau’s Labhttp://www.seas.harvard.edu/haulab/

• The art of taming light: ultra-slow and stopped light, Zachary Dutton et al., Europhysics News (2004) Vol. 35 No. 2http://www.europhysicsnews.com/full/26/article1/article1.html

Presentation soon available at www.osa-latvia.lv