This Small Business Innovation Research (SBIR) Phase II project focuses on the commercialization of multichannel holographic spectrometers featured large operating bandwidth and fine spectral resolution. The proposed research is to develop a new platform for spectrometers using multiplexed cylindrical beam volume holograms (MCBVHs) as dispersive elements. Due to its unique characteristic, the MCBVH enables the design of two-dimensional (2D) spatial-spectral output patterns to significantly enhance the functionality of holographic spectrometers. A significant improvement of the operating bandwidth can be achieved without sacrificing spectral resolution while keeping all merits of a compact, lightweight, low-cost, reliable, and alignment robust holographic spectrometer. With the proposed multichannel spectrometer, several species of interest can be detected at one shot even though their spectrums are distributed in a very large spectral bandwidth. Due to the design flexibility of volume holograms, this technology enables the design of spectrometers with custom functionalities. Breaking the resolution-bandwidth trade-off of the conventional spectrometers with a holographic system that does not increase the complexity of the final product is the major breakthrough expected from this project. The expected outcome of this project will be a simplest yet highly functional spectrometer that can be designed to perform for technically any given application criteria.
The broader impact/commercial potential of this project is to provide an enabling technology for spectral sensor systems which offer great utility to the life science and medical markets. For high throughput screening, it is desired to have multiple channels read simultaneously on a test containing multiple sample sites. For fluorescence based tests, multiple fluorophores need to be quantified requiring more spectral information. Maintaining good sensitivity is still required in these applications for low concentration detection at a low cost and size demanded by these markets. The proposed multichannel spectrometer based on MCBVHs will have a broad range of applications in the fields of biochemistry, medicine, pharmaceuticals, industrial quality assurance, homeland security, mineralogy, and environmental monitoring. Moreover, the compact and lightweight nature of the proposed spectrometer makes it a perfect choice for handheld sensing devices that are of high current demand in several fields as mentioned above. The entire US market volume that can be covered by this technology has been $2.6B in 2005, with a prospected 7% growth rate through 2010. The use of sophisticated volume holograms with 2D spatial-spectral output patterns is an important enabling technology that can impact the design of custom multi-purpose spectrometers/sensors beyond the proposed functionalities.
using cylindrical beam volume holograms. With the support of this grant, we have completed the optimization on both the volume hologram and spectroscopic system, and accomplished a working holographic spectrometer prototype with its own software. The company has demonstrated technologies and prototypes in several major exhibitions (including Photonics West 2010, Photonics West 2011, and Pittcon 2011), and drawn wide-spread interest from customers. However, we have not been able to commit to the potential buyers because of the lack of volume holographic materials. Our innovative holographic spectrometer is built in significantly different concept and structure from conventional spectrometers invented for more than a century ago. It features a sophisticated volume hologram which can perform the functions of an entrance slit, a collimation lens, and a grating. Without the requirement of a slit and input coupling in the system, this spectrometer has a wide open input aperture (in the range of several centimeters in diameter) providing high throughput especially for the spectral measurement of large area diffuse light sources. Moreover, with as few as three elements (a volume hologram, a Fourier transforming lens, and a detector), this spectrometer is ultra-compact, robust, and inexpensive. For one of the spectrometers developed in this project, the hologram is used to project several regions of diffracted spectra to obtain both wide wavelength range and high optical resolution. In conventional spectrometers range and resolution are trade-offs – you gain one at the expense of the other. This technology has potential to address high-end spectrometer market while large spectral range, high resolution, and compactness are all demanded simultaneously. For the other spectrometer developed in this project, a piece of volume hologram is used to turn a regular camera into a spectrometer. This enabling technology provides the capability to make an ultra-compact spectrometer as an accessory for all popular mobile devices such as smartphones and tablets.
