Presented at SPIE BiOS, 2022
Proceedings Volume 11953, Optical Fibers and Sensors for Medical Diagnostics, Treatment
and Environmental Applications XXII; 119530G (2022)
This paper describes the modeling, deposition, lithographic patterning, and testing of filters directly deposited onto the distal tip of a fiber bundle. These spectrally sharp bandpass and long pass filters allow for the detection of Raman scattering down to about 200 cm-1 . Blocking of laser radiation above OD6 is enabled by coating both the distal and proximal tips.
Omega offers several options for laser-line filtering and laser-wavelength blocking for Raman spectroscopy applications. Our hard coatings care prepared using plasma-assisted reactive magnetron sputtering for exceptional durability, low scatter, high blocking and high transmission at the desired wavelength.
US Patent # 9,155,474
Inventors: Gary E. Carver, Sheetal K. Chanda, William A. Morrison, Sarah A. Locknar, Robert L. Johnson, Jr.
This 2015 patent describes a fiber-based confocal scanning system that indexes spectral information into the time domain. It enables the detection of up to 15 spectral bins within 2.5 microseconds using a single PMT detector. The technology leverages Omega's thin-film optics expertise with a serial array of coated fiber tips in the detection path. Omega has perfected the art of fiber-tip coating to accomplish this work.
To understand blocking, one has to understand the concept of optical density (OD). In an interference filter, OD is generated by reflecting unwanted light back instead of letting it go through the filter.