Various embodiments disclosed herein describe an infrared (IR) imaging system for detecting a gas. The imaging system can include an optical filter that selectively passes light having a wavelength in a range of 1585 nm to 1595 nm while attenuating light at wavelengths above 1600 nm and below 1580 nm. The system can include an optical detector array sensitive to light having a wavelength of 1590 that is positioned rear of the optical filter.

The disclosed embodiments include thin film multivariate optical element and detector combinations, thin film optical detectors, and downhole optical computing systems. In one embodiment, a thin film multivariate optical element and detector combination includes at least one layer of multivariate optical element having patterns that manipulate at least one spectrum of optical signals. The thin film multivariate optical element and detector combination also includes at least one layer of detector film that converts optical signals into electrical signals. The thin film optical detector further includes a substrate. The at least one layer of multivariate optical element and the at least one layer of detector film are deposited on the substrate.

Methods use a tunable notch filter for constructing a spectral map of electromagnetic radiation in a selected spectral band that is incident on a notch filter for a plurality of time periods. Electromagnetic radiation is passed by an electronically tuned notch filter to a detector array for the plurality of selected time periods, and the detector response is determined. For at least a first selected time period the notch filter is tuned to selectively attenuate the passing of one or more selected sub-bands of electromagnetic radiation in the selected spectral band. Information about the selectively attenuated radiation is determined and used along with information about the radiation passed to the detector array for each time period to construct a spectral map. Electronically tunable notch filters may be made with metamaterials such as patterned graphene.

An optical module 100 includes a first substrate 11 including an optical filter device 7 having a wavelength variable interference filter 110 built therein, a second substrate 12 including a light receiving element 17, and a first supporter 16 that mechanically or electrically joins the first substrate 11 and the second substrate 12 to each other, in which the wavelength variable interference filter 110 and the light receiving element 17 are disposed to face each other by the first supporter 16, and the first substrate 11 and the second substrate 12 are joined to each other by the first supporter 16 with a gap S1 in which a circuit element 21 is mountable.

Aspects of the present disclosure are directed to a reconfigurable interference device comprising a phase change structure. The phase change structure comprises a solid-state phase change material having a first phase state and a second phase state dependent on temperature. A first energy source is configured to supply an initialization energy to initialize a plurality of domains having the first phase state and a second energy source is configured to supply an electrical current to the structure to position the plurality of domains of the first phase state within the phase change structure. A control unit is configured to control the first and the second energy source and to create a periodic interference pattern comprising a plurality of domains of the first phase state and a plurality of domains of the second phase state in an alternating pattern.

An interferometer includes a holding element having an actuation recess, a first mirror element arranged on the holding element opposite the actuation recess, and a second mirror element arranged opposite the first mirror element at a mirror distance, to form an optical slit. The first mirror element is arranged between the second mirror element and the holding element and the optical slit is spatially separated from the actuation recess by the first mirror element. The interferometer further includes an electrode pair including a first actuation electrode in one of the mirror elements and a second actuation electrode on a side of the actuation recess opposite the first actuation electrode. The mirror distance can be varied by applying an electrical voltage to the electrode pair.

An example method and hyperspectral imaging (HSI) system for imaging a scene are provided. The method is for imaging the scene with the HSI system including a sensor with a plurality of sensor pixels and a plurality of spectral filters, each of the spectral filters being associated with one of the sensor pixels. The method comprises obtaining a higher-resolution spatial image by illuminating the scene with a first set of wavelengths, wherein each spectral filter passes the first set of wavelengths to the sensor pixel it is associated with. The method further comprises obtaining a lower-resolution hyperspectral image by illuminating the scene with a second set of wavelengths, wherein each spectral filter passes only a subset of the second set of wavelengths to the sensor pixel it is associated with.

A tunable notch filter for operation in reflection mode comprises an antenna layer positioned on a transmissive substrate and a mirror layer positioned on a support substrate. The antenna layer and the mirror layer are positioned on opposite sides of a gap and facing each other, the gap having a gap distance. The notch filter is tuned by adjusting the gap distance between the antenna layer and the mirror layer. Tuning the notch filter to a selected state can cause the filter to selectively attenuate the reflection of at least some electromagnetic radiation that is incident on the transmissive substrate and enters the notch filter.

Various embodiments disclosed herein describe an infrared (IR) imaging system for detecting a gas. The imaging system can include an optical filter that selectively passes light having a wavelength in a range of 1585 nm to 1595 nm while attenuating light at wavelengths above 1600 nm and below 1580 nm. The system can include an optical detector array sensitive to light having a wavelength of 1590 that is positioned rear of the optical filter.

A tunable optical filter, includes a light source configured to emit optical radiation to a sample; an input optical element configured to receive optical radiation reflected from the sample; a liquid crystal cell comprising electrodes, the liquid crystal cell contacting the input optical element; an output optical element, contacting the liquid crystal cell; and a control unit adapted to apply a preset voltage to the liquid crystal cell via the electrodes; wherein the input optical element and the output optical element have a same first refractive index, wherein, when voltage is not applied to the liquid crystal cell, the first refractive index is greater than a second refractive index of the liquid crystal cell for a wavelength range of incident optical radiation, and wherein the input optical element, the liquid crystal cell and the output optical element are tilted at an angle to the incident optical radiation.