RUI: Microwave to Optical Frequency Conversion Through Six-wave Mixing

St. Norbert College, De Pere WI

Investigators

Abstract

General audience abstract: Quantum computation and optical communication require coherent light sources over a wide range of frequencies. The ability to convert between the “telecom” wavelengths used in optical fiber networks and those used for atomic systems in quantum computation is an important part of furthering communications technology, and would allow more effective information sharing throughout society. This work focuses on the fundamental quantitative interactions between atoms and light, and how these interactions can be used to generate coherent sources at novel wavelengths. Atoms in highly energetic quantum states have been shown to be extremely sensitive to microwaves, providing the impetus for their use in microwave to optical frequency conversion. Many promising quantum computation schemes use microwave transitions to control quantum states, while optical fiber technology makes use of high transmission in the infrared. As a result, this frequency conversion could be an essential part of coupling quantum computation systems to telecom systems. Additionally, as a Research in Undergraduate Institutions project, this work will have a significant effect on the further development of the experimental physics workforce, helping to prepare and motivate undergraduate students for careers in science by developing their skills in experimental technique, data analysis, computation, and scientific communication. Technical audience abstract: Using four lasers which are readily attainable, hot rubidium atoms can be used to generate a coherent infrared source dependent on the application of microwaves or vice-versa. The process makes use of rubidium atoms excited to Rydberg levels with n>50, such that transitions between nearby states are resonant with microwave frequencies. The primary objective of this work is to demonstrate the feasibility of using six-wave mixing in hot rubidium atoms as a microwave-infrared frequency conversion method. Through the simultaneous application of multiple lasers connecting atomic states in a process called wave mixing, new directional and coherent light sources, both optical and microwave, will be produced and the process of their generation optimized. Power and frequency characteristics of their output will be explored as a function of the power, polarization and frequency of the input sources, as well as the Rydberg state used. This research will provide analysis of wave mixing in rubidium atoms, which has the potential to greatly advance the scientific community's understanding of six-wave mixing. While four-wave mixing has been extensively investigated and used, higher wave-mixing remains relatively unexplored. The use of higher wave-mixing allows the exploration of novel wavelengths for coherent light while still using common and convenient atomic systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.