This Small Business Innovation Research (SBIR) Phase II project focuses on the commercialization of a new class of ultra-compact, low-cost, robust, and alignment insensitive spectrometer for diffuse source spectroscopy with lower cost and considerably better overall performance compared to conventional slit-based spectrometers. Intellectual merits: The spectrometers available in the current market are based on core technologies invented around one hundred years ago. The main problems of the traditional spectrometers are being bulky, sensitive to input alignment, relatively expensive, and low optical throughput, because narrow slits, lenses, high quality thin gratings, and the detector array are required in the system. As the portability, cost, and sensitivity are top concerns in recent biological and environmental sensing applications, a new class of spectrometers that satisfy those needs is in high demand. The proposed research is to commercialize an ultra-compact, low-cost, robust, and alignment insensitive spectrometer, which is composed of only a volume hologram and a detector array. The operation frequency range and the spectral bandwidth of the proposed spectrometers cover the requirements of most practical applications. The spectrometers can also be used to form special-purpose functional spectrometers with any desired spectral transfer function.
If successful the proposed spectrometer will have a broad range of applications in the fields of biochemistry, medicine, pharmaceuticals, industrial quality assurance, homeland security, mineralogy, and environmental purposes. Specifically, in the applications where the light source has a diffuse nature (e.g., fluorescence spectroscopy) the developed spectrometer will show the best sensitivity among all the existing technologies. The ultra-compact lightweight nature of the proposed spectrometers makes them a perfect choice for handheld sensing devices that are of high current demand in several fields 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 volume holograms (which are typically recorded in low-cost materials like photopolymers) to replace multiple bulky optics (e.g., slit, collimating lens, and Fourier transforming lens in the case of spectrometer) is an important enabling technology that can impact several applications (e.g., imaging and sensing) beyond the proposed functionalities.
The objective of this NSF SBIR Phase II project is to commercialize an ultra-compact, low-cost, robust, and alignment insensitive spectrometer using 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 operation software. The prototype has also been demonstrated in several major exhibitions such as Photonics West 2010, Photonics West 2011, and Pittcon 2011. Using our volume holographic technology, the 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. With its excellent design flexibility, special-purpose functions can be incorporated into a volume hologram without adding any complexity to the hardware system of the spectrometer. This volume holographic technology allows us to develop custom spectrometers/analyzers for unique applications. It also opens up a new application for volume holography research field. Furthermore, the use of volume holograms to replace multiple bulky optics (e.g., slit, collimating lens, and Fourier transforming lens in the case of spectrometer) is an important enabling technology that can impact several applications and instrumentations (e.g., imaging and sensing systems) beyond the functionalities implemented in our current holographic spectrometer prototype.
