SBIR-STTR Award

This SBIR Phase I proposal describes a method of fabrication of far IR and THZ range multilayer metal-mesh filters. This type of filter consists of alternative layers of polymer material and structured thin metal films. The proposed filters are radiation hard and lightweight. The fabrication process proposed will increase the availability of such filters and expand the market while reducing the cost and delivery time. In Phase I, it is proposed to develop a process for incorporating the dielectric film in between the metal mesh and to maintain the mechanical integrity over the wide temperature range (from below 4K to 300K). In Phase II, optimized filters will be fabricated and their properties compared with design predictions. Phase III will involve product design, fabricating filter structures to meet customers' physical as well as optical needs, and marketing and sales investments. Anticipated

Benefits:
Narrow band pass, band pass and band blocking filters for THz frequency range filters are expected to find market in THz imaging, a technique that is targeting many applications spanning from defense and security applications (seeing through dust, camouflage, barriers) to medical applications (replacement of X-rays). Potential customers include manufacturers of THz imaging and THz sensing systems. Lake Shore proposes to utilize the materials, which while providing sufficiently low losses at THz region, could be used in large-scale fabrication compatible processes, thus permitting the reduction of the cost of filters and making them more attractive to aforementioned market. NASA applications of far IR and submillimeter wave filters include upper atmosphere studies and observations, study and observations of astronomical objects (our galaxy and beyond). Far IR and submillimeter wavelengths are particularly important for investigation of the statistics and physics of galaxy and structure formation at high red-shift and the study of the earliest stages of star formation, when the protostar is still coupled to the interstellar medium. Galaxies emit a large portion (from 30% to nearly 100%) of their total energy output in the far IR due to re-processing of stellar UV radiation by interstellar dust grains.

The innovative, high transmission band-pass filter technology proposed here is an improvement in multilayer metal-mesh filter design and manufacture for the far IR to submillimeter ranges. The proposed metal-mesh filters can tolerate cryogenic temperatures (down to 4K and below) and a wide vibration/shock spectrum, making them launch-capable and durable for long periods in space. In addition, the proposed band-pass filters are light weight, as they employ no heavy substrates. The proposed 2 5 mm thickness (mostly the mounting frame) allows insertion into tight spaces and standard filter wheels. The thin, light weight, vacuum compatible design can be incorporated into almost any detector setup. Large sizes can be manufactured for newer instruments with larger diameter beams. Anticipated

Benefits:
Lake Shore's proven track record in commercializing advanced technologies along with being an established supplier to NASA makes us confident we can further commercialize our metal-mesh filter technology upon developing standard multi-layer designs. Earth-based astronomy programs have a need and will continue to have a need for improved IR band pass filters, dichroic filters among other optical components. University astrophysics research, missle defense applications, and infrared, submillimeter, and Thz spectrometer manufacturing (improve broadband detector performance with filtering) are all markets that are actively growing and show a need for band-pass filters. Improvements in the detector sensitivity and format have enabled significant development of the capabilities in the far-IR and submillimeter spectral regime, in the last few years. Detector arrays have improved from hundreds to thousands or millions of pixels, which has led to rapid dispersive (i.e. diffraction-grating) spectroscopy of multiple sources in multiple far IR wavebands simultaneously. In astrophysics, sensitive far IR spectroscopy from actively-cooled space telescopes can reveal the history of galaxies, heavy-element production, and black-hole growth since the very first stars. There are a number of astronomy programs such as, SOFIA, SPICA/BLISS, SAFIR, SPIRIT that will use far IR spectrometers for optimal science discovery. Other projects such as CLARREO are designed to provide a measure of the earth's radiation budget, reveal distribution of key greenhouse gases, and probing the role of high altitude clouds could use sensitive far IR spectroscopy to improve its capabilities by orders of magnitude.