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We talk with mechanical engineer Tim Quinn about advances being made in the world of photonics, wave–particle duality, and optical computing in this episode of The Engineering Commons.

• Carmen is pleased that Google Fiber is coming to his neighborhood.
• Our guest for this episode is Tim Quinn, a design engineer who works for Thorlabs in Newton, New Jersey.
• Carmen asks if Thorlabs has established operations in the realm of Asgard.
• Tim participated in Formula SAE while attending Rutgers University.
• Photonics is the study of how light (whether visible or not) is generated, transmitted, modulated, detected, and amplified.
• A photon is the quantum for electromagnetic radiation. An electron absorbs or emits photons as it moves between atomic orbitals.
• Photomultiplier tubes are sensitive to the presence of visible, ultraviolet, and near-infrared light, allowing a single photon to be detected under the proper conditions.
• A charge-coupled device (CCD) is also able to detect photons, producing an increased number of charge carriers in response to heightened light levels. Not all photons will be sensed by a CCD; quantum efficiency describes the percentage of photons actually detected.
• Carmen asks about the difficulty of detecting a single photon.
• Tim thinks we’re still at least a decade away from practical applications of optical computing.
• Photons have a spin of 1, while electrons have a spin of 1/2.
• Jeff notes that optical computing might come of age just in time to keep Moore’s Law intact for another generation. Tim references a recent Wall Street Journal article (subscription required) about this matter.
• We chuckle recalling Dr. Evil’s desire for sharks with lasers.
• Tim notes that quantum cascade lasers are gaining in popularity, due to their high power output, wavelength tunability, and room temperature operation.
• Metrology is the science of measurement.
• One can measure minute dimensional differences using a Michelson interferometer.
• Lasers are used in direct metal laser sintering (DMLS) to form a solid part from powdered metal (YouTube video).
• Bicycle parts are being printed using DMLS.
• Mechanical compaction is a more traditional method for forming powdered metals in advance of sintering.
• Fiber Bragg gratings are but one of many applications for fiber optics in civil engineering.
• Advances continue to be made in manufacturing light-emitting diodes (LEDs), especially in blue wavelengths.
• LED lightbulbs are rapidly dropping in price; at the time of this episode a 60W (equivalent) bulb could be purchased for less than $3 at major retailers in the United States.
• Two-Photon Excitation Fluorescence Microscopy allows living tissue to be imaged to a depth of about one millimeter.
• A chemical compound that emits light upon absorbing energy from incoming light (of a higher frequency) is known as a fluorophore.
• Optogenetics is the science of using light to control neurons.
• The new Apple Watch uses reflective photoplethysmography to determine a user’s heart rate.
• Originally founded in 1955 as the Society of Photographic Instrumentation Engineers, the SPIE is now the leading professional society for optics and photonics technology.
• Globars emit radiation composed of wavelengths from approximately 4000 to 15,000 nanometers, and are often used as thermal light sources for infrared spectroscopy. By comparison, visible light falls in a range between 380 and 780 nm, while sunlight spans wavelengths from 100 to 1,000,000 nm.
• Our guest notes that the University of Arizona has a well-respected photonics program.
• Tim recommends an article from Laser Focus World magazine for those interested in pursuing a photonics-related career.
• Information about the photonics industry is also available at Photonics.com.
• Our guest can be contacted via email: tquinn -=+ at +=- thorlabs dot com, or timothy dot quinn dot jr -=+ at +=- gmail dot com.

Thanks to Steve Jurvetson for use of the image titled “Puddles of Light.” Podcast theme music by Paul Stevenson.