High efficiency optical modulation at a telecom wavelength using the quantum Zeno effect in a ladder transition in Rb atoms.
We demonstrate a high-efficiency optical modulator at ~1323 nm using the quantum Zeno effect in a ladder transition in a Rb vapor cell. The lower leg of the transitions represents the control beam while the upper leg of the transitions represents the signal beam. The cross-modulation of the signal beam transmission is observed as the control beam is intensity modulated, and is explained in terms of the quantum Zeno effect. We observe a modulation depth of near 100% at frequencies up to 1 MHz and demonstrate modulation at speeds up to 75 MHz, with a 3 dB bandwidth of about 5 MHz, limited by the homogeneous linewidth of the intermediate state. We also describe how much higher modulation speeds could be realized by using a buffer gas to broaden the transitions. We identify and explain the special conditions needed for optimizing the modulation efficiency. Numerical simulations of modulation at ~1 GHz are presented. The maximum modulation speed is found to scale with the pressure-broadened linewidth of the intermediate state, so that much higher speeds should be attainable.
Department of EECS, Northwestern University, Evanston, Illinois 60208, USA.
Subramanian
S
Krishnamurthy
Y
Y
Wang
Y
Y
Tu
S
S
Tseng
M S
MS
Shahriar
D003198:Computer Simulation; D005740:Gases / Q000737:chemistry*; D008027:Light; D008956:Models, Chemical; D011789:Quantum Theory; D012031:Refractometry / Q000379:methods*; D012413:Rubidium / Q000737:chemistry*; D012542:Scattering, Radiation; D013685:Telecommunications
D005740:Gases; D012413:Rubidium