A spectral imaging device (12) includes an image sensor (28), a tunable light source (14), an optical assembly (17), and a control system (30). The optical assembly (17) includes a first refractive element (24A) and a second refractive element (24B) that are spaced apart from one another by a first separation distance. The refractive elements (24A) (24B) have an element optical thickness and a Fourier space component of the optical frequency dependent transmittance function. Further, the element optical thickness of each refractive element (24A) (24B) and the first separation distance are set such that the Fourier space components of the optical frequency dependent transmittance function of each refractive element (24A) (24B) fall outside a Fourier space measurement passband.

Conventional optical analysis tools containing an integrated computational element may have an operational profile that is too large for convenient use within confined locales. Optical analysis tools having a miniaturized operational profile can comprise: an electromagnetic radiation source that provides electromagnetic radiation to an optical train; and an optical computing device positioned within the optical train. The optical computing device comprises a planar array detector having at least two optical detection regions. At least one of the at least two optical detection regions has an integrated computational element disposed thereon. The planar array detector and the integrated computational element are in a fixed configuration with respect to one another.

Detection sensitivity of optical computing devices may be improved by utilizing multiple integrated computational elements in combination with one another. Optical computing devices containing multiple integrated computational elements may comprise: two or more integrated computational elements that are identical to one another and optically interact sequentially with incident electromagnetic radiation, such that at least a portion of the photons from the incident electromagnetic radiation optically interacts with each integrated computational element; wherein the sequential optical interaction of the incident electromagnetic radiation with the two or more integrated computational elements increases a detection sensitivity of the optical computing device relative to that obtained when only one of the integrated computational elements is present; and a detector that receives the photons that have optically interacted with each integrated computational element.

According to an example, a first mirror layer may be formed on a substrate. A first set of spacer layers may be deposited on the first mirror layer to be positioned above a first group of the sensing elements and a second set of spacer layers may be deposited on the first mirror layer to be positioned above a second group of the sensing elements, in which the second set of spacer layers differs from the first set. In addition, a second mirror layer may be formed above the deposited first set of spacer layers and the deposited second set of spacer layers.

Technologies are described for monitoring characteristics of layers of integrated computational elements (ICEs) during fabrication using an in-situ spectrometer operated in step-scan mode in combination with lock-in or time-gated detection. As part of the step-scan mode, a wavelength selecting element of the spectrometer is discretely scanned to provide spectrally different instances of probe-light, such that each of the spectrally different instances of the probe-light is provided for a finite time interval. Additionally, an instance of the probe-light interacted during the finite time interval with the ICE layers includes a modulation that is being detected by the lock-in or time-gated detection over the finite time interval.

A compact spectrometer is disclosed that is suitable for use in mobile devices such as cellular telephones. In preferred embodiments, the spectrometer comprises a filter, at least one Fourier transform focusing element, a micro-lens array, and a detector, but does not use any dispersive elements. Methods for using the spectrometer as an end-user device for performing on-site determinations of food quality, in particular, by comparison with an updatable database accessible by all users of the device, are also disclosed.

The present disclosure provides a near-infrared absorbing filter, including an absorbing type infrared filtering medium having opposite first and second surfaces; an organic coating layer formed on the first surface of the absorbing type filtering medium for absorbing infrared rays; a first multi-layered film structure formed on the organic coating layer with the organic coating layer disposed between the first multi-layered film structure and the absorbing type infrared filtering medium; and a second multi-layered film structure formed on the second surface of the absorbing type infrared filtering medium. The near-infrared filter of the present disclosure is able to reduce the wavelength difference of T50 and T20 of the incident light within the range of from 0 to 30 degrees to less than 5 nm, thereby reducing chromatic aberration effectively and reducing ghost images of infrared reflections. The disclosure further provides an image sensor including the near-infrared absorbing filter.

Optical computing devices may include capacitance-based nanomaterial detectors. For example, an optical computing device may include a light source that emits electromagnetic radiation into an optical train extending from the light source to a capacitance-based nanomaterial detector; a material positioned in the optical train to optically interact with the electromagnetic radiation and produce optically interacted light; and the capacitance-based nanomaterial detector comprising one or more nano-sized materials configured to have a resonantly-tuned absorption spectrum and being configured to receive the optically interacted light, apply a vector related to the characteristic of interest to the optically interacted light using the resonantly-tuned absorption spectrum, and generate an output signal indicative of the characteristic of interest.

A spectrometer device includes an optical interference filter which is designed to filter specific wavelength ranges of an incident light beam on passage through the optical interference filter. The spectrometer device also includes a detector device which is designed to detect the filtered light beam. Further, the spectrometer device includes a focusing device with a reflective surface. The focusing device is designed to focus the filtered light beam onto the detector device by reflection on the surface.

In an embodiment, an optoelectronic measuring device 1ncludes a first detector configured to provide a first detector signal, a second detector configured to provide a second detector signal, wherein each of the first detector and the second detector is configured to detect electromagnetic radiation, a signal difference determiner configured to generate a difference signal by subtracting the second detector signal from the first detector signal and a spectral filter arranged in a beam path upstream of the second detector, wherein the spectral filter is configured to filter the electromagnetic radiation before detection by the second detector, wherein the optoelectronic measuring device is configured to measure an intensity of the electromagnetic radiation impinging on the optoelectronic measuring device.