L
Leo T. Varghese
Researcher at Purdue University
Publications - 55
Citations - 2200
Leo T. Varghese is an academic researcher from Purdue University. The author has contributed to research in topics: Optical isolator & Silicon photonics. The author has an hindex of 15, co-authored 55 publications receiving 1938 citations.
Papers
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Journal ArticleDOI
An All-Silicon Passive Optical Diode
Li Fan,Jian Wang,Leo T. Varghese,Hao Shen,Ben Niu,Yi Xuan,Andrew M. Weiner,Minghao Qi,Minghao Qi +8 more
TL;DR: The device, which uses two silicon rings 5 micrometers in radius, is passive yet maintains optical nonreciprocity for a broad range of input power levels, and it performs equally well even if the backward input power is higher than the forward input.
Journal ArticleDOI
Spectral line-by-line pulse shaping of on-chip microresonator frequency combs
Fahmida Ferdous,Houxun Miao,Houxun Miao,Daniel E. Leaird,Kartik Srinivasan,Jian Wang,Lei Chen,Leo T. Varghese,Andrew M. Weiner +8 more
TL;DR: In this paper, the authors demonstrate the line-by-line pulse shaping of frequency combs generated in silicon nitride ring resonators, and observe two distinct paths to comb formation that exhibit strikingly different time domain behaviours.
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High-Q silicon nitride microresonators exhibiting low-power frequency comb initiation
Yi Xuan,Yang Liu,Leo T. Varghese,Andrew J. Metcalf,Xiaoxiao Xue,Pei-Hsun Wang,Kyunghun Han,Jose A. Jaramillo-Villegas,Abdullah Al Noman,Cong Wang,Sangsik Kim,Min Teng,Yun Jo Lee,Ben Niu,Li Fan,Jian Wang,Daniel E. Leaird,Andrew M. Weiner,Minghao Qi +18 more
TL;DR: In this article, a fabrication procedure that leads to the demonstration of "finger-shaped" Si3N4 microresonators with intrinsic Qs up to 17 million at a free spectrum range (FSR) of 24.7 GHz that are suitable for telecommunication and microwave photonics applications.
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Surface Modification of Cetyltrimethylammonium Bromide-Capped Gold Nanorods to Make Molecular Probes
TL;DR: Gold nanorod molecular probes (GNrMPs) were fabricated by subsequent attachment of antibodies to the activated GNRs and were used to visualize and detect cell surface biomarkers in normal and transformed human breast epithelial cells, demonstrating the potential of developing novel biosensors using gold nanorods.
Journal ArticleDOI
Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip.
Jian Wang,Hao Shen,Li Fan,Rui Wu,Ben Niu,Leo T. Varghese,Yi Xuan,Daniel E. Leaird,Xi Wang,Fuwan Gan,Andrew M. Weiner,Minghao Qi +11 more
TL;DR: The on-chip optical delay elements offer an integrated approach to accurately manipulating individual radio-frequency waveform features without constraints set by the speed and timing jitter of electronics, and should find applications ranging from high-speed wireless to defence electronics.