2019 SPIE Defense + Commercial Sensing
CMS presentation during the 2019 DCS in Baltimore
On Wednesday, April 17 at 1:45 pm, Dr. Mark White will present an overview of “Ultralow-loss mid-IR interference coatings via substrate transfer and direct bonding” during the industry event held on the exhibition floor at the 2019 Defense + Commercial Sensing conference in Baltimore, Maryland.
Substrate-transferred crystalline coatings have emerged as a groundbreaking new concept in high-performance optical interference coatings. Building upon the initial demonstration of this technology in 2013, significant improvements have been realized in the optical performance of these novel single-crystal GaAs/AlGaAs multilayers for both near- and mid-infrared wavelengths. For center wavelengths spanning 1064 to 1560 nm, the excess optical losses (scatter + absorption) have been determined to be less than 5 ppm, with sub-ppm optical absorption directly measured. Near a center wavelength of 1550 nm, these coatings have enabled the realization of a linear cavity with a finesse exceeding 600,000.
Extending this technology to the mid-IR spectral region (2 to 5 μm), our GaAs/AlGaAs-based semiconductor supermirrors have continued to show exceptionally low optical losses. For example, excess losses of less than 50 ppm were measured by cavity ringdown on the first prototype mirrors at 4.5 µm. The combination of wide spectral bandwidth with low optical absorption offers unique possibilities for mid-IR applications with this enabling coating technology. Given their unique advantages, crystalline coatings are currently redefining the performance metrics for applications requiring the ultimate levels of optical, thermal, and optomechanical performance.