Abstract:
A variable-wavelength interference filter includes: a first substrate; a second substrate facing the first substrate; a first reflection layer provided on a surface facing the second substrate, of the first substrate; a second reflection layer which is provided on a surface facing the first substrate, of the second substrate, and faces the first reflection layer via an inter-layer gap; and an electrostatic actuator which flexes the second substrate in a direction toward the first substrate and thus changes the inter-layer gap. The first reflection layer and the second reflection layer have a reflectance characteristic showing a higher reflectance to light with a second wavelength that is shorter than a first wavelength, than a reflectance to light with the first wavelength.
Abstract:
A system for remotely sensing a target material in situ include a broad-band laser source, at least one tunable filter coupled to the source laser for generating a swept-frequency signal an optical device for splitting the swept-frequency signal into a first illumination signal and second illumination signal, a first optical path for directing the first illumination signal unto the target material and receiving a reflected signal from the target material, a second optical path for receiving the second illumination signal and generating a spectral reference signal, and a controller coupled to the first optical path and the second optical path for adjusting the frequency and spatial resolution of the laser source based at least in part on a comparison of the spectral reference signal and the reflected signal.
Abstract:
A spectrum sensing method includes (a) receiving an incident radiation simultaneously through a filter array composed of multiple bandpass filters, (b) digitizing spectral responses of the filter array, and (c) generating an estimate of spectral profile of the incident radiation based on digitized spectral responses of the filter array.
Abstract:
A fast switching arbitrary frequency light source for broadband spectroscopic applications. The light source may operate near 1.6 um based on sideband tuning using an electro-optic modulator driven by an arbitrary waveform generator. A Fabry-Perot filter cavity selects a single sideband of the light source. The finesse (FSR/ΔνFWHM) of the filter cavity may be chosen to enable rapid frequency switching at rates up to 5 MHz over a frequency range of 40 GHz (1.3 cm−1). The bandwidth, speed and spectral purity are high enough for spectroscopic applications where rapid and discrete frequency scans are needed. Significant signal-to-noise advantages may be realized using the rapid and broadband scanning features of this system in many areas of spectroscopy, e.g., process monitoring and control, reaction dynamics, and remote sensing (e.g., greenhouse gas monitoring, biological/chemical agent screening).
Abstract:
A method of manufacturing a spectroscopic sensor 1 comprises a first step of forming a cavity layer 21 by nanoimprinting on a handle substrate; a second step of forming a first mirror layer 22 on the cavity layer 21 after the first step; a third step of joining a light-transmitting substrate 3 onto the first mirror layer 22 after the second step; a fourth step of removing the handle substrate from the cavity layer 21 after the third step; a fifth step of forming a second mirror layer 23 on the cavity layer 21 without the handle substrate after the fourth step; and a sixth step of joining the light detection substrate 4 onto the second mirror layer 23 after the fifth step.
Abstract:
Systems for generating uniform monochromatic electromagnetic radiation that include an electromagnetic radiation source and a bandpass filter assembly to filter electromagnetic radiation emitted by the electromagnetic radiation source. The systems also include an optical integrating sphere to receive the filtered electromagnetic radiation and to uniformly scatter the filtered electromagnetic radiation within the optical integrating sphere, wherein the optical integrating sphere comprises an output to emit the uniformly scattered, filtered electromagnetic radiation.
Abstract:
Micro-spectral sensors and methods are presented in which a Fizeau wedge interference filter is disposed between a focal plane array and a visible scene with an increasing wedge filter dimension varying along a scan direction, where the scene is scanned along the FPA to obtain light intensity measurements of a given scene location at different times using different FPA sensor elements through different wedge filter thicknesses, and the measurements correlated to the given scene location are Fourier transform to generate spectral data for the location.
Abstract:
The present invention discloses a multi-cavity optical sensing and thermopile infrared sensing system, which comprises an optical sensing part, a dielectric layer, a plurality of optical cavities, and a plurality of thermocouples. The dielectric layer covers on the top of the optical sensing part. The optical cavities are formed by a plurality of metal reflectors inside the dielectric layer. The thermocouples are laterally disposed near the bottom of the dielectric layer. In addition, a low temperature region is formed in an area which is the overlapping of vertical projections of such thermocouples and the optical sensing part; a high temperature region is formed by the overlapping of vertical projections of such thermocouples, but without the overlaying which belongs to the vertical projection of the optical sensing part. Therefore, the system can sense the ambient light brightness, color conditions and human blackbody infrared signals within the range of 8-12 micrometers wavelength.
Abstract:
A spectrophotometer includes a fixed substrate having a fixed reflecting film, a movable substrate having a movable reflecting film, a tunable interference filter having a static actuator changing the gap distance of an inter-reflecting film gap between the fixed reflecting film and the movable reflecting film, a detecting section detecting the light intensity of a light extracted by the tunable interference filter, a voltage setting section and a voltage controlling section that apply a continuously-varying analog voltage to the static actuator, a voltage monitoring section monitoring the voltage applied to the static actuator, and a light intensity obtaining section obtaining the light intensity detected by the detecting section when the voltage monitored by the voltage monitoring section becomes a predetermined voltage to be measured.
Abstract:
A sensor assembly having an optical fiber, a lens in optical communication with the optical fiber, a reflective surface spaced from the lens, for reflecting light from the beam back to the lens, a partially reflective surface positioned between the reflective surface and the lens, the partially reflective surface for reflecting light from the beam back to the lens, and an alignment device for aligning the lens and reflective surface with respect to one another, such that light from the beam of light transmitted from the lens reflects from the reflective surface back to the lens. The alignment device can have a rotational component and a base component, where the rotational component rotates to align a beam of light transmitted from the lens. The rotational component can also cooperate with the base component to move axially with respect to the reflective surfaces to align the beam for optimum power.