First Infrared Chromium and Iron doped zinc selenide Fiber Lasers

A collaboration between our group and that of  my colleague, late John V. Badding has led to the first demonstration of fiber lasers with ZnSe core.  These ZnSe cores, deposited inside silica capillary using High Pressure Chemical Vapor Deposition invented by Badding group and doped with either Cr2+ or Fe2+ are ideal for infrared emission from 2-4 micron wavelengths.  In collaboration with Ken Schepler, Gary Cook, Sean McDaniel, and Mike Coco from the Air Force, we have indeed demonstrated the first such fiber lasers.  The Cr2+:ZnSe work has appeared in Optical Materials Express recently.  The Fe2+:ZnSe work is accepted in Optics Express, and will appear shortly.

Wedge Reversion: A New Antisymmetry

What is chiral in one dimension is not chiral in a higher dimension.

Wedge Reversion antisymmetry was introduced as a means to classify all physical quantities in arbitrary dimensions.  The above image shows that an object that is chiral in N dimensions is no longer chiral in N+1 dimensions, and hence chirality is not a good metric to classify physical quantities.  Instead a new operation, Wedge reversion allows for such classification in arbitrary dimensions.  A recent article led by Hari and Jason in the Annual Reviews of Materials Research reviews this and other important antisymmetries and their applications.  Gopalan gave a zoom seminar at the Pittsburg Quantum Institute (PQI) on Sept 18, 2020 on this topic.  The video recording of the talk is on Youtube at this link.