Description
The ability to convert quantum signals between the microwave and optical domains is an important tool in quantum information processing. Here, we use a room-temperature ensemble of $^{87}{\rm Rb}$ atoms inside a microwave cavity to generate an optical signal whose frequency is the sum of an optical pump and a hyperfine microwave control field, using hybrid sum-frequency generation [1]. By using a multimode microwave control field, the generated optical field carries the same multiple-frequency character, which can be as broad as the 300-kHz cavity linewidth and tunable across the 0.5-GHz Doppler spectrum. This process, which leverages electromagnetically-induced transparency between the two optical fields, results in a “slow-light” time delay of the converted field, where the delay time depends on the power of the microwave control field [2].
Using these techniques, our gaseous atomic system acts in analogy to an electro-optic modulator, which, with its capacity to operate under ultra-low pumping powers, makes it a promising platform for quantum frequency processing [3] across several orders of magnitude in the frequency domain.
Figure 1. (a) In the nonlinear sum-frequency generation process, microwave frequency $\omega_\mu$ and optical frequency $\omega_c$ combine to produce an optical frequency at $\omega_p = \omega_\mu + \omega_c$. (b) Diagram of the experimental setup. Microwave signal generator (SG), spectrum analyzer (SA), acousto-optic modulator (AOM), external cavity diode laser (EDCL), photodiode (PD), quarter waveplate (QWP), amplifier (AMP).
[1] K. V. Adwaith, A. Karigowda, C. Manwatkar, F. Bretenaker, and A. Narayanan. "Coherent microwave-to-optical conversion by three-wave mixing in a room temperature atomic system." Opt. Lett. 44 1 (2019).
[2] J. K. Saaswath, K. N. Pradosh, K. V. Adwaith, B. C. Sanders, F. Bretenaker, and A. Narayanan. "Microwave-driven generation and group delay control of optical pulses from an ultra-dilute atomic ensemble." Opt. Express 29 11 (2021).
[3] H.-H. Lu, J. M. Lukens, N. A. Peters, O. D. Odele, D. E. Leaird, A. M. Weiner, and P. Lougovski. "Electro-optic frequency beam splitters and tritters for high-fidelity photonic quantum information processing." Phys. Rev. Lett. 120 030502 (2018).
| Presenter name | Benjamin D. Smith |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
