The objective of this research is to investigate applications of optical frequency combs in photonic signal processing and atomic-molecular-optical (AMO) physics. The approach is to acquire a state of the art, commercial frequency comb laser to enable new experimental studies.
In ultrafast photonics the frequency comb will enable generation of optical and radio-frequency signals with instantaneous bandwidth and long-term jitter properties significantly better than available by conventional technologies. In AMO physics research, the frequency comb will enable driving coherent optical transitions involving very different transition frequencies, and will be an invaluable tool, for example, to create ground state molecules via photoassociation for current research aiming to use such molecules for quantum computing. Furthermore, the proposed equipment is expected to catalyze new interdisciplinary collaborations involving both disciplines.
The proposed equipment will provide rich opportunities for broad student training in areas of cutting-edge technology and enable new research impacting optical and wireless communications, both areas with direct societal impact, and quantum computing, an emerging area with potential for revolutionary impact in the long term. Broader impact is also anticipated through a variety of activities in which the proposing faculty are engaged. For example, Weiner is currently Chair of the National Academy of Engineering?s Frontiers of Engineering conference, considered to be an important career development opportunity for future engineering leaders, while Elliott is active in diversity issues, as evidenced by his term as Director of Graduate Recruitment and Retention Programs at Purdue?s College of Engineering.
This grant provided funding for purchase of an instrument known as a femtosecond frequency comb laser. Based on revolutionary developments in laser technology that were recognized with the 2005 Nobel Prize in Physics, this laser system provides a highly stabilized sequence of ultrashort optical pulses. The pulses are composed of an equally spaced set (comb) of optical frequencies that can be used as a ruler for measuring optical frequencies with unprecedented precision. This instrument has been purchased and installed in the Ultrafast Optics and Fiber Communications Laboratory at Purdue University and has been successfully running for more than one and one half years. Intellectual merit: The special properties of the frequency comb laser enhance and contribute to significant new research at Purdue both in ultrafast, broadband photonic signal processing and atomic-molecular-optical (AMO) physics. One project in ultrafast photonics involves generation of high repetition rate frequency combs from microresonators on optical chips. Such a source of combs has the potential for very small footprint but (at least so far) does not provide the level or precision and accuracy supplied by a stabilized bulk lasers (like the frequency comb laser purchased under this grant). We are actively using the purchased frequency comb laser to carefully measure important properties of our microresonators, both to guide device development and to test theories describing their comb generation operation. This research has been funded both by NSF and subsequently by the Department of Defense. In a second research topic related to optical signal processing, we are using the frequency comb laser as a light source for experiments exploring novel photonic means for creating very high bandwidth radio-frequency electrical signals. Such signals are useful both for indoor wireless communications and high resolution radar imaging. In the area of AMO physics, the frequency comb laser is being used to support a research program aimed at cooling and trapping of lithium and rubidium atoms in a dual species magneto-optical trap (MOT) and then photoassociating ultra-cold atoms in order to produce a sample of ultra-cold lithium-rubidium (LiRb) molecules. The overall goal of this work is to control the internal quantum state of the LiRb molecules and explore their applications in quantum logic operations. Broader impact: The purchased equipment enables new research impacting on the one hand optical and wireless communications, both areas with direct societal impact, and on the other hand quantum computing, an emerging area with potential for revolutionary impact in the long term. The proposed equipment also enhances rich opportunities for broad student training in areas of cutting-edge technology. More than one half a dozen graduate students as well as a postdoctoral research associate have participated in research using the purchased instrument. Finally, the Principal Investigator (PI) of this grant has been named Editor-in-Chief (EiC) of Optics Express, one of the most active journals in the optics field. This appointment became effective Jan. 1, 2013. In this capacity the PI directly contributes to the leadership of one of the most important forums for dissemination of research results in his field. In his capacity as EiC, one of the PIâ€™s duties is to help identify papers for press releases and other forms of publicity of potential interest to the general public. (Note that this editorial appointment is not funded in any way by the current grant.)