John Wallace

Senior Technical Editor (1998-2022)
Phone: (603) 891-9228

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

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Laser Focus World’s top 20 photonics technology picks for 2021

Dec. 1, 2021
In 2021, advances in optics and photonics encompass the fields of laser optics, integrated photonics, quantum optical systems, and much more.
A spectroscopic gemstone-screening instrument allows rapid separation of natural from synthetic diamonds. Shown are the experimental fluorescence spectra from natural, HPHT-grown, and CVD-grown diamonds. N3 fluorescence at 415 nm was only detected in natural diamonds.
A spectroscopic gemstone-screening instrument allows rapid separation of natural from synthetic diamonds. Shown are the experimental fluorescence spectra from natural, HPHT-grown, and CVD-grown diamonds. N3 fluorescence at 415 nm was only detected in natural diamonds.
A spectroscopic gemstone-screening instrument allows rapid separation of natural from synthetic diamonds. Shown are the experimental fluorescence spectra from natural, HPHT-grown, and CVD-grown diamonds. N3 fluorescence at 415 nm was only detected in natural diamonds.
A spectroscopic gemstone-screening instrument allows rapid separation of natural from synthetic diamonds. Shown are the experimental fluorescence spectra from natural, HPHT-grown, and CVD-grown diamonds. N3 fluorescence at 415 nm was only detected in natural diamonds.
A spectroscopic gemstone-screening instrument allows rapid separation of natural from synthetic diamonds. Shown are the experimental fluorescence spectra from natural, HPHT-grown, and CVD-grown diamonds. N3 fluorescence at 415 nm was only detected in natural diamonds.
Test & Measurement

Spectroscopic gemstone screener rapidly identifies natural and synthetic diamonds

July 21, 2021
A UV-fluorescence spectroscopy-based instrument with a handheld probe identifies various types of diamonds, as well as diamond fakes such as corundum, spinel, and beryl.
In the ALPHA-2 experiment, antihydrogen atoms are trapped and laser Doppler-cooled to enable antimatter experimentation. At the center of the experiment’s vacuum chamber, magnetically trapped antihydrogen atoms are cooled via light at a 121.6 nm wavelength, which matches the Lyman-alpha line of hydrogen. Light at 243.1 nm is used to observe the spectral line of the atoms’ 1S-2S transition.
In the ALPHA-2 experiment, antihydrogen atoms are trapped and laser Doppler-cooled to enable antimatter experimentation. At the center of the experiment’s vacuum chamber, magnetically trapped antihydrogen atoms are cooled via light at a 121.6 nm wavelength, which matches the Lyman-alpha line of hydrogen. Light at 243.1 nm is used to observe the spectral line of the atoms’ 1S-2S transition.
In the ALPHA-2 experiment, antihydrogen atoms are trapped and laser Doppler-cooled to enable antimatter experimentation. At the center of the experiment’s vacuum chamber, magnetically trapped antihydrogen atoms are cooled via light at a 121.6 nm wavelength, which matches the Lyman-alpha line of hydrogen. Light at 243.1 nm is used to observe the spectral line of the atoms’ 1S-2S transition.
In the ALPHA-2 experiment, antihydrogen atoms are trapped and laser Doppler-cooled to enable antimatter experimentation. At the center of the experiment’s vacuum chamber, magnetically trapped antihydrogen atoms are cooled via light at a 121.6 nm wavelength, which matches the Lyman-alpha line of hydrogen. Light at 243.1 nm is used to observe the spectral line of the atoms’ 1S-2S transition.
In the ALPHA-2 experiment, antihydrogen atoms are trapped and laser Doppler-cooled to enable antimatter experimentation. At the center of the experiment’s vacuum chamber, magnetically trapped antihydrogen atoms are cooled via light at a 121.6 nm wavelength, which matches the Lyman-alpha line of hydrogen. Light at 243.1 nm is used to observe the spectral line of the atoms’ 1S-2S transition.
Lasers & Sources

Trapping and laser cooling of antihydrogen points to advances in antimatter experimentation

May 19, 2021
Making, magnetically trapping, and laser cooling antihydrogen atoms via laser Doppler cooling leads to a stable assemblage of anti-atoms suitable for next-generation physics experiments...