Dispersion multiplexing with broadband filtering for miniature spectrometers

Abstract

We replace the traditional grating used in a dispersive spectrometer with a multiplex holographic grating to increase the spectral range sensed by the instrument. The multiplexed grating allows us to measure three different, overlapping spectral bands on a color digital focal plane. The detector's broadband color filters, along with a computational inversion algorithm, let us disambiguate measurements made from the three bands. The overlapping spectral bands allow us to measure a greater spectral bandwidth than a traditional spectrometer with the same sized detector. Additionally, our spectrometer uses a static coded aperture mask in the place of a slit. The aperture mask allows increased light throughput, offsetting the photon loss at the broadband filters. We present our proof-of-concept dispersion multiplexing spectrometer design with experimental measurements to verify its operation.

Real‐time in vivo cancer diagnosis using raman spectroscopy

“…The highly sensitive multimodal multiplex spectrometer (MMS) system uses an extended aperture mask in place of a conventional entrance slit . Cull et al incorporates multiplexing holographic grating capable of dispersing three spectral ranges simultaneously to increase the spectral sensing range . The system is a doubly multiplexed spectrometer using both coded aperture and dispersion multiplexing.…”

Two-dimensional barcodes for mobile phones

“…However, the red light leaking into blue pixels and the blue light leaking into red pixels is less significant due to the spectral response of Bayer filter, which is a function of wavelength. The spectral response of some typical Bayer filters can be found at [76,77,78]. Figure 3.24, taken from [76], illustrates the response for a particular Bayer filter.…”

“…The spectral response of some typical Bayer filters can be found at [76,77,78]. Figure 3.24, taken from [76], illustrates the response for a particular Bayer filter. It should be noted however, than the Bayer filter colour responses vary and that this example does not accurately represent all camera sensors.…”

“…While it was expected that red would have a higher capacity than blue by a small factor (red generally has a higher sensitivity response in Bayer filters [76,77,78]), red outperformed blue by a factor of 50%. This was partly because the colour mixing into red was less substantial.…”

Compressive Optical Imaging Systems -- Theory, Devices and Implementation

“…Both imagers are completely static, single-shot designs, resulting in mechanically robust and inexpensive systems. In these respects the system architectures are a descendant of the coded-aperture spectroscopy architecture previously developed by several of the current authors [44][45][46][47][48]. In our first extension to spectral imaging [43], however, the implementation required a sequence of exposures in order to measure the contents of the spectral data cube.…”