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Search Publications by

Varun Verma (Fed)

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Displaying 1 - 25 of 54

Single-photon detection in the mid-infrared up to 10 micron wavelength using tungsten silicide superconducting nanowire detectors

September 14, 2021
Varun Verma, Adriana Lita, Yao Zhai, Heli C. Vora, Richard Mirin, Sae Woo Nam, Boris Korzh, Alex Walter, Ryan Briggs, Marco Colangelo, Emma Wollman, Andrew Beyer, Jason Allmaras, D. Zhu, Ekkehart Schmidt, A. G. Kozorezov, Matthew Shaw
We developed superconducting nanowire single-photon detectors (SNSPDs) based on tungsten silicide (WSi) that show saturated internal detection efficiency up to a wavelength of 10 um. These detectors are promising for applications in the mid-infrared

State Readout of a Trapped Ion Qubit Using a Trap-integrated Superconducting Photon Detector

January 6, 2021
Susanna L. Todaro, Varun Verma, Katherine C. McCormick, David T. Allcock, Richard Mirin, David J. Wineland, Sae Woo Nam, Andrew C. Wilson, Dietrich Leibfried, Daniel Slichter
We detect fluorescence photons emitted by a single $^9$Be$^+$ ion confined in a surface- electrode rf ion trap, using a superconducting nanowire single photon detector integrated directly into the trap. We achieve a qubit readout fidelity of 99.91(1) %

Superconducting microwire detectors with single-photon sensitivity in the near-infrared

June 16, 2020
Jeffrey T. Chiles, Sonia M. Buckley, Adriana E. Lita, Varun B. Verma, Jeffrey M. Shainline, Richard P. Mirin, Sae Woo Nam, Jason Allmaras, Boris Korzh, Emma Wollman, Matthew Shaw
We report on the fabrication and characterization of single-photon-sensitive WSi superconducting detectors with wire widths from 1 υm to 3 υm. The devices achieve saturated internal detection efficiency at 1.55 υm wavelength and exhibit maximum count rates

Tunable quantum beat of single photons enabled by nonlinear nanophotonics

November 22, 2019
Qing Li, Anshuman Singh, Xiyuan Lu, John Lawall, Varun Verma, Richard Mirin, Sae Woo Nam, Kartik Srinivasan
Integrated photonics is a promising approach for scalable implementation of diverse quantum resources at the chip-scale. Here, we demonstrate the integration of two essential building blocks for quantum information science - quantum sources and frequency

Quantum Frequency Conversion of a Quantum Dot Single-Photon Source on a Nanophotonic Chip

May 20, 2019
Anshuman Singh, Qing Li, Shunfa Liu, Ying Yu, Xiyuan Lu, Christian Schneider, Sven Hofling, John Lawall, Varun Verma, Richard Mirin, Sae Woo Nam, Jin Liu, Kartik Srinivasan
Single self-assembled InAs/GaAs quantum dots are promising bright sources of indistinguishable photons for quantum information science. However, their distribution in emission wavelength, due to inhomogeneous broadening inherent to their growth, has

Towards a source of entangled photon pairs in gallium phosphide

May 9, 2019
Paulina S. Kuo, Peter G. Schunemann, Mackenzie Van Camp, Varun B. Verma, Thomas Gerrits, Sae Woo Nam, Richard P. Mirin
We investigate parametric down-conversion in orientation-patterned GaP. Pumped at 865 nm, the signal and idler are at 1350 nm and 2400 nm, respectively.

Generating polarization-entangled photon pairs in domain-engineered PPLN

May 7, 2019
Paulina S. Kuo, Varun B. Verma, Thomas Gerrits, Sae Woo Nam, Richard P. Mirin
Using a periodically poled LiNbO3 crystal that is domain-engineered for two simultaneous type-II down-conversion processes, we demonstrated polarization-entangled photon-pair generation.

Single self-assembled InAs/GaAs quantum dots in photonic nanostructures: the role of nanofabrication

June 13, 2018
Jin Liu, Kumarasiri Konthasinghe, Marcelo I. Davanco, John Lawall, Vikas Anant, Varun Verma, Richard Mirin, Jin Dong Song, Ben Ma, Ze Sheng Chen, Hai Qiao Ni, Zhi Chuan Niu, Kartik Srinivasan
Single self-assembled InAs/GaAs quantum dots are a promising solid-state quantum technology, with vacuum Rabi splitting, single-photon-level nonlinearities, and bright, pure, and indistinguishable single-photon generation having been demonstrated. In such

Short-wave infrared compressive imaging of single photons

June 6, 2018
Thomas Gerrits, Daniel Lum, Varun B. Verma, John Howell, Richard P. Mirin, Sae Woo Nam
We present a short-wave infrared (SWIR) single photon camera based on a single superconducting nanowire single photon detector (SNSPD) and compressive imaging. We show SWIR single photon imaging at a megapixel resolution with a low signal-to-background

Heterogeneous integration for on-chip quantum photonic circuits with single quantum dot devices

October 12, 2017
Marcelo I. Davanco, Liu Jin, Luca Sapienza, Chen-Zhao Zhang, Jose Vinicius De Miranda Cardoso, Varun B. Verma, Richard P. Mirin, Sae Woo Nam, Liu Liu, Kartik A. Srinivasan
Photonic integration is establishing itself as an enabling technology for photonic quantum science, offering considerably greater scalability, stability, and functionality than traditional bulk optics. Here, we develop a scalable, heterogeneous III-V /

Towards integrated superconducting detectors on lithium niobate waveguides

August 29, 2017
Jan P. Hoepker, Moritz Bartnick, Evan Meyer-Scott, Frederik Thiele, Stephan Krapick, Nicola Montaut, Matteo Santandrea, Harald Herrmann, Sebastian Lengeling, Raimund Ricken, Victor Quiring, Torsten Meier, Adriana Lita, Varun Verma, Thomas Gerrits, Sae Woo Nam, Christine Silberhorn, Tim J. Bartley
Superconducting detectors are now well-established tools for low-light optics, and in particular quantum optics, boasting high-efficiency, fast response and low noise. Similarly, lithium niobate is an important platform for integrated optics given its

Bandwidth-enhanced superconducting nanowire single photon detectors for telecom wavelengths

May 14, 2017
Stephan Krapick, Marina Hesselberg, Varun Verma, Igor Vayshenker, Sae Woo Nam, Richard Mirin
We present a single-photon detector providing system detection efficiencies of at least (86.7 ± 0.9) % from 1450 nm to 1640 nm. It comprises bilayer superconducting WSi nanowires in conjunction with all-dielectric structures for optical impedance matching

UV-sensitive superconducting nanowire single photon detectors for integration in an ion trap

April 17, 2017
Daniel H. Slichter, Varun B. Verma, Dietrich G. Leibfried, Richard P. Mirin, Sae Woo Nam, David J. Wineland
We demonstrate superconducting nanowire single photon detectors with 76 +/- 4% system detection efficiency at a wavelength of 315 nm and an operating temperature of 3.2 K, with a background count rate below 1 count per second at saturated detection

A quantum enigma machine: Experimentally demonstrating quantum data locking

August 12, 2016
Daniel Lum, Michael S. Allman, Thomas Gerrits, Cosmo Lupo, Seth Lloyd, Varun Verma, Sae Woo Nam, John Howell
During the first half of the 20th century, enigma machines (i.e., pseudorandom polyalphabetic ciphers) of increasing sophistication gave better resistance against brute-force codebreaking attacks. However, the ultimate form of cryptographic security is

Demonstration of EPR steering using single-photon path entanglement and displacement-based detection

August 12, 2016
T Guerreiro, F. Monteiro, A Martin, J B. Brask, T Vertesi, Boris Korzh, Felix Bussieres, Varun Verma, Adriana Lita, Richard Mirin, Sae Woo Nam, Francesco Marsili, Matthew D. Shaw, Nicolas Gisin, Nicolas Brunner, Hugo Zbinden, Robert Thew
We demonstrate the violation of an EPR steering inequality developed for single photon path entanglement with displacement-based detection. We use a high-rate source of heralded single-photon path-entangled states, combined with high efficiency

Experimental investigation of the detection mechanism in WSi nanowire superconducting single photon detectors

July 18, 2016
Rosalinda Gaudio, Jelmer J. Renema, Zili Zhou, Varun Verma, Jeff Shainline, Martin Stevens, Richard Mirin, Sae Woo Nam, Martin P. van Exter, Michiel J. de Dood, Andrea Fiore
We use quantum detector tomography to investigate the detection mechanism in WSi nanowire superconducting single photon detectors (SSPDs). To this purpose, we fabricated a 250 nm wide and 250 nm long WSi nanowire and measured its response to impinging

Athermal avalanche in bilayer superconducting nanowire single-photon detectors

March 28, 2016
Varun B. Verma, Martin J. Stevens, Richard P. Mirin, Sae Woo Nam
We demonstrate that two superconducting nanowires separated by a thin insulating barrier can undergo a thermal avalanche process. In this process, Joule heating caused by a photodetection event in one nanowire and the associated production of athermal

Hotspot Relaxation Dynamics in a Current Carrying Superconductor

March 17, 2016
Francesco Marsili, Martin Stevens, Alex Kozorezov, Varun Verma, Colin Lambert, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Matthew Shaw, Richard Mirin, Sae Woo Nam
When a photon is absorbed in a superconductor it creates a region of nonequilibrium superconductivity referred to as a hotspot [1]. The operation of most superconducting single photon detectors (microwave kinetic inductance detectors, MKIDs [2,3]