Dr. Alan W. M. Lee Profile

Dr. Alan W. M. Lee

at LongWave Photonics LLC

Websites:

Company Website

Dr. Lee is President of LongWave Photonics LLC (longwavephotonics.com), and is currently developing terahertz quantum cascade lasers and systems for Astronomy and non-destructive test. This technology was developed from his graduate research from the Millimeter Wave and Terahertz Group at the Massachusetts Institute of Technology.

Proceedings Article | 17 August 2024 Presentation

Compact terahertz spectrometer based on a metasurface

Wenye Ji, Jin Chang, Behnam Mirzaei, Marcel Ridder, Willem Jellema, Wilt Kao, Alan Lee, Jian Rong Gao, Paul Urbach, Aurèle J. Adam

Proceedings Volume PC13102, PC131020I (2024) https://doi.org/10.1117/12.3021392

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Proceedings Article | 16 August 2024 Presentation + Paper

Virtually Image Phased Array (VIPA): demonstration of the next generation direct detection spectrometer for velocity resolved spectroscopy in the far-infrared

Thomas Nikola, Bugao Zou, Gordon Stacey, Jake Connors, Nicholas Cothard, Alexander Kutyrev, Eric Mentzell, Karwan Rostem, Edward Wollack, Willem Jellema, Tsung-Yu Kao, Alan W. Lee

Proceedings Volume 13102, 131020F (2024) https://doi.org/10.1117/12.3020350

KEYWORDS: Cryostats, Quantum cascade lasers, Spectral resolution, Silicon, Reflectivity, Collimation, Spectroscopy, Mirrors, Parabolic mirrors, Dielectrics

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We have created and demonstrated a Virtually Imaged Phased Array (VIPA) device for velocity resolved spectroscopy in the far-IR and will present the first cryogenic (LHe) measurements of the spectral profile of a prototype VIPA at 115.7 µm. A VIPA is a compact spectral filter without moving parts that consists of a resonating cavity that generates angular dispersion due to constructive interference, and that can deliver an instantaneous spectrum with a resolving power of 100,000 or more. Coupled with superconducting direct detection detectors, the VIPA promises unsurpassed sensitivity at velocity resolutions > 3 km/s, making it a prime choice for spectroscopic instruments to observe e.g. protoplanetary disks to trace the gaseous building blocks out of which planets form. Due to their compactness and absence of moving parts, VIPAs are optimal for balloon and space-borne astronomical instruments like the NASA Pioneer Mission POEMM and the proposed NASA Probe Mission FIRSST. The prototype we have measured was made of a 3 × 5 × 1 cm block of high-purity float-zone silicon. The entrance and exit sides of the VIPA are highly parallel, and the entrance side was fully metallized (gold-coated) except for a narrow entrance slit resulting in a reflectivity of 100%, while the exit side was metallized with an inductive mesh resulting in a reflectivity of about 88%. The measurement was done using a custom testbed that included separate cryostats for a cryogenically cooled THz Quantum Cascade Laser (QCL) and the VIPA, as well as a warm pyroelectric detector. The QCL was tuned to a number of different frequencies near 2.59 THz and the detector was scanned along the dispersion direction. Our VIPA prototype achieved the designed resolving power of 15,000 and the spectral profile matched extremely well with the expectations from our simulations. We are now building a full testbed to straightforwardly measure and characterize VIPAs and other GHz/THz filters with resolving powers of order 100,000 using tuneable THz lasers.

Proceedings Article | 26 May 2016 Paper

Terahertz imaging with quantum cascade lasers

Alan Lee, Tsung-Yu Kao, Ian Zimmerman, Naoki Oda, Qing Hu

Proceedings Volume 9854, 98540R (2016) https://doi.org/10.1117/12.2224140

KEYWORDS: Quantum cascade lasers, Terahertz radiation, Sensors, Microbolometers, Imaging systems, Metals, Nondestructive evaluation, Silicon, Staring arrays, Interfaces

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Proceedings Article | 25 May 2016 Paper

THz QCLs for heterodyne receivers and wavelength modulation spectroscopy

Alan W. Lee, Tsung-Yu Kao, Ian Zimmerman, William T. Cole, Richard Thurston, Richard Saykally, Ningren Han, Qing Hu

Proceedings Volume 9836, 98362O (2016) https://doi.org/10.1117/12.2224158

KEYWORDS: Terahertz radiation, Quantum cascade lasers, Heterodyning, Receivers, Modulation, Sensors, Absorption, Signal detection, Spectroscopes, Microelectromechanical systems

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Proceedings Article | 23 February 2013 Paper

Terahertz quantum cascade laser based optical coherence tomography

Alan Lee, Tsung-Yu Kao, Qing Hu, John Reno

Proceedings Volume 8585, 858508 (2013) https://doi.org/10.1117/12.2001127

KEYWORDS: Quantum cascade lasers, Terahertz radiation, Interfaces, Mirrors, Optical coherence tomography, Tomography, Dielectrics, Antennas, Neodymium, Interferometers

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Proceedings Article | 15 October 2012 Paper

Real-time transmission-type terahertz microscope with palm size terahertz camera and compact quantum cascade laser

Naoki Oda, Tsutomu Ishi, Takao Morimoto, Takayuki Sudou, Hitoshi Tabata, Shunsuke Kawabe, Kyohei Fukuda, Alan W. Lee, Qing Hu

Proceedings Volume 8496, 84960Q (2012) https://doi.org/10.1117/12.928564

KEYWORDS: Terahertz radiation, Quantum cascade lasers, Microscopes, Cameras, Signal to noise ratio, Spatial filters, Silicon, Optical filters, Transmittance, Infrared radiation

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Proceedings Article | 9 May 2012 Open Access

Proposal for real-time terahertz imaging system with palm-size terahertz camera and compact quantum cascade laser

Naoki Oda, Alan W. Lee, Tsutomu Ishi, Iwao Hosako, Qing Hu

Proceedings Volume 8363, 83630A (2012) https://doi.org/10.1117/12.917682

KEYWORDS: Terahertz radiation, Quantum cascade lasers, Cameras, Microbolometers, Imaging systems, Signal to noise ratio, Waveguides, Silicon, Absorption, Microscopes

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Proceedings Article | 29 January 2008 Paper

High-temperature and high-power operation of terahertz quantum-cascade lasers

Sushil Kumar, Alan Lee, Qi Qin, Benjamin Williams, Qing Hu, John Reno

Proceedings Volume 6909, 69090I (2008) https://doi.org/10.1117/12.768298

KEYWORDS: Waveguides, Quantum cascade lasers, Terahertz radiation, Reflectivity, Pulsed laser operation, Gallium arsenide, Mirrors, Wave propagation, Radio propagation, Semiconducting wafers

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