Transmittting light with lateral variation

• US 8,594,470 B2
• Filed: 05/07/2013
• Issued: 11/26/2013
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Kiesel, Peter, Schmidt, Oliver
• Primary Examiner(s): Le, Uyen Chau N
• Assistant Examiner(s): Prince, Kajli
• Application Number:
  US13/888,708
• Publication Number:
  US 20130240706A1
• Time in Patent Office: 203 Days
• Field of Search: 385/12
• US Class Current: 385/12
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/024 using means for illuminating a slit efficiently (e.g. entrance slit of a spectrometer or entrance face of fiber)
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 9/00 Measuring optical phase difference devices or arrangements for controlling the phase of light beams G02F1/01; Determining degree of coherence; Measuring optical wavelength spectrometry G01J3/00
• CPC Class Codes: G02B 5/008 Surface plasmon devices diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553
• CPC Class Codes: G02B 5/284 of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26
• CPC Class Codes: G02B 6/29317 Light guides of the optical fibre type
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection

Abstract

Input light, such as from an optical sensor or stimulus-wavelength converter, includes one or more light or dark sub-bands. The input light is transmitted, such as through a transmissive layer or transmission component, to obtain effects due to transmission with lateral variation. A detector can, for example, obtain spectral information or other photon energy information about the sub-bands due to lateral variation. For each light or dark sub-band, a transmission component can, for example, provide a respective light or dark spot, and spot position can be used to obtain spectral information such as absolute wavelength or wavelength change. A photosensing component can sense or detect transmitted light or output photons, such as with a photosensor array or a position-sensitive detector. Circuitry can use photosensed quantities to obtain, e.g. a differential signal or information about time of wavelength change.

Claims

1. A detection system, comprising:

a detector comprising at least one layer, the detector including;

a transmission component that includes at least one layer with laterally varying transmission properties, the transmission component configured to, when illuminated with input light, output sub-bands of optical wavelengths at respective positions along an output surface of the transmission component, including at least a first sub-band output at a first position of the transmission component output surface and a second sub-band output at a second position of the transmission component output surface; and

a photosensing component configured to receive the one or more sub-bands of optical wavelengths output by the transmission component and to generate signals in response to the sub-bands of optical wavelengths, including generating a first signal responsive to the first sub-band and a second signal responsive to the second sub-band; and

circuitry configured to determine changes in the first and second signals over time and to generate an output signal that includes information about wavelength changes in the sub-bands output from the transmission.

2. The system of claim 1 in which the transmission component includes at least one of:

a two-dimensional grating sensor;

a reflective grating sensor;

a guided mode resonant fiber sensor;

a plastic optical fiber sensor;

an optical fiber sensor with one or more fiber Bragg gratings;

a photonic crystal sensor;

an optical cavity sensor;

a surface Plasmon resonance sensor;

a temperature sensor; and

an optical biosensor.

3. The system of claim 1 in which the detector further includes at least one of:

a photosensor array with CCD readout;

a photosensor array with CMOS readout;

a one-dimensional photosensor array;

a two-dimensional photosensor array;

one or more discrete photosensing devices;

one or more avalanche photodiodes;

one or more photomultiplier tubes;

a position sensitive detector;

a differential amplifier;

circuitry that provides a differential signal; and

circuitry that obtains information about times of wavelength change.

4. The system of claim 1 in which the at least one layer includes at least one of:

a coating;

a wedge-shaped transmission cavity between reflective films;

a staircase-shaped transmission cavity between reflective films;

a laterally graded Bragg mirror with laterally graded layers;

a layer with two-dimensional variation in optical thickness;

a layer with laterally varying thickness; and

a layer with laterally varying refractive index.

5. Apparatus comprising:

a stimulus-wavelength converter that provides light within a photon energy range, the converter providing light in first and second sub-bands of the photon energy range in response to first and second values of a stimulus, respectively;

a transmission structure with entry and exit surfaces, the exit surface including first and second positions;

the transmission structure being a layered structure; and

a propagation component that propagates light from the converter to the transmission structure'"'"'s entry surface;

the transmission structure providing photons at the first and second positions of the exit surface in response to light received at its entry surface;

the stimulus wavelength converter, propagation component, and transmission structure being configured so that, due to transmission of light with lateral variation, relative quantities of photons provided at the first and second positions change over time in response to change over time between the first and second sub-bands and to output a signal indicating the change over time.

6. The apparatus of claim 5 in which the stimulus-wavelength converter includes at least one of:

one or more optical fibers;

a photonic crystal;

an optical cavity;

a fluorescent analyte;

one or more fiber Bragg gratings;

a Fabry-Perot structure;

an optical biosensor;

a sensor that responds to change over time in at least one of temperature, pressure, strain, stress, flow, level, speed or rpm, position, orientation, motion, acceleration, presence or absence of an analyte, rain, thickness, liquid quality, breakage, or magnetic field;

a fiber end facet from which the converter provides light;

a point-like source from which the converter provides light; and

a broad area source from which the converter provides light.

7. The apparatus of claim 5 in which at least one of:

the photon energy range is a broad band and the first and second sub-bands are narrow bands;

the first and second sub-bands are light sub-bands;

the first and second sub-bands are dark sub-bands;

the first and second sub-bands have respective first and second peak energy values; and

the first and second sub-bands have respective first and second minimal energy values.

8. The apparatus of claim 5 in which at least one of:

the transmission structure has a laterally varying transmission function due to laterally varying thickness;

the transmission structure has a laterally varying transmission function due to laterally varying refractive index;

the transmission structure has a constant transmission gradient;

the transmission structure has a step-like transmission gradient;

the stimulus-wavelength converter, the propagation component, and the transmission structure are configured so that the transmission structure'"'"'s entry surface receives light from the converter across a range of incident angles;

the propagation component includes an optical fiber that receives light from the converter and guides the light to the transmission structure'"'"'s entry surface; and

the propagation component is a spreading component.

9. A method of using the apparatus of claim 5, comprising:

photosensing quantities of photons provided at the first and second positions of the transmission structure'"'"'s exit surface, the act of photosensing quantities being performed over time; and

identifying time of change in relative quantities provided at the first and second positions and using the identified time of change to obtain information about time of change between the first and second stimulus values.

10. A detection system, comprising:

an optical sensor that, when illuminated with a broad band of optical wavelengths, outputs approximately the broad band of optical wavelengths with a dark sub-band; and

a detector that includes one or more transmissive layers;

the optical sensor and the detector being configured so that the detector receives light output by the optical sensor and, due to transmission of light with lateral variation, transmits light in at least two sets of wavelengths in the broad band at a respective position of the layers, the detector configured to compare a change over time of positions of the light transmitted in each set of wavelengths to determine wavelength changes of the dark sub-band in the output from the optical sensor responsive to the change over time of the positions of the light transmitted in each set of wavelengths.

11. The system of claim 10 in which the optical sensor includes at least one of:

a two-dimensional grating sensor;

a reflective grating sensor;

a guided mode resonant fiber sensor;

a plastic optical fiber sensor;

an optical fiber sensor with one or more fiber Bragg gratings;

a photonic crystal sensor;

an optical cavity sensor;

a surface Plasmon resonance sensor;

a temperature sensor; and

an optical biosensor.

12. The system of claim 10 in which the detector further includes at least one of:

a photosensor array with CCD readout;

a photosensor array with CMOS readout;

a one-dimensional photosensor array;

a two-dimensional photosensor array;

one or more discrete photosensing devices;

one or more avalanche photodiodes;

one or more photomultiplier tubes;

a position-sensitive detector;

a differential amplifier;

circuitry that provides a differential signal; and

circuitry that obtains information about times of wavelength change.

13. The system of claim 10 in which the transmissive layers include at least one of:

a coating;

a wedge-shaped transmission cavity between reflective films;

a staircase-shaped transmission cavity between reflective films;

a laterally graded Bragg mirror with laterally graded layers;

a layer with two-dimensional variation in optical thickness;

a layer with laterally varying thickness; and

a layer with laterally varying refractive index.

14. The system of claim 10 in which at least one of:

the transmissive layers include at least one layer that has a laterally varying transmission function; and

the optical sensor and the detector are configured so that the detector receives light from the optical sensor across a range of incident angles.