Polarization selective, frequency selective, and wide dynamic range detectors, imaging arrays, readout integrated circuits, and sensor systems

Patent metadata

Field	Value
Publication number	US-9939322-B2
Application number	US-201615542425-A
Country	US
Kind code	B2
Filing date	Jan 8, 2016
Priority date	Jan 9, 2015
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

This relates to sensor systems, detectors, imagers, and readout integrated circuits (ROICs) configured to selectively detect one or more frequencies or polarizations of light, capable of operating with a wide dynamic range, or any combination thereof. In some examples, the detector can include one or more light absorbers; the patterns and/or properties of a light absorber can be configured based on the desired measurement wavelength range and/or polarization direction. In some examples, the detector can comprise a plurality of at least partially overlapping light absorbers for enhanced dynamic range detection. In some examples, the detector can be capable of electrostatic tuning for one or more flux levels by varying the response time or sensitivity to account for various flux levels. In some examples, the ROIC can be capable of dynamically adjusting at least one of the frame rate integrating capacitance, and power of the illumination source.

First claim

What is claimed is:

1. A light detector, comprising:
a first light absorber configured to:
select first light from incident light, and
absorb the selected first light,
wherein the first light absorber includes one or more first features, the one or more first features including at least one of a plurality of first slits, a first mesh, and a first plate absorber, the one or more first features selective to the selected first light;

a first temperature sensor thermally coupled to the first light absorber; and
a second light absorber configured to:
select second light from the incident light, and
absorb the selected second light,
wherein the second light absorber includes one or more second features, the one or more second features including at least one of a plurality of second slits, a second mesh, and a second plate absorber, the one or more second features selective to the selected second light.

2. The light detector of claim 1 , wherein the first light absorber includes the plurality of first slits oriented in a first polarizing direction, and the second light absorber includes the plurality of second slits oriented in a second polarizing direction, different from the first polarizing direction.

3. The light detector of claim 2 , wherein the second polarizing direction is orthogonal to the first polarizing direction.

4. The light detector of claim 2 , further comprising:
a third light absorber configured to:
select third light from the incident light, and
absorb the selected third light,
wherein the third light absorber includes a plurality of third slits oriented in a third polarizing direction, orthogonal to the first polarizing direction;

a third temperature sensor thermally coupled to the third light absorber;
a fourth light absorber configured to:
select fourth light from the incident light, and
absorb the selected fourth light,
wherein the fourth light absorber includes a plurality of fourth slits oriented in a fourth polarizing direction, orthogonal to the second polarizing direction; and

a fourth temperature sensor thermally coupled to the fourth light absorber.

5. The light detector of claim 1 , further comprising:
a second temperature sensor thermally coupled to the second light absorber,
wherein the first and second temperature sensors are electrically coupled, and the light detector is capable of determining an angle of polarization of light absorbed by the first and second light absorbers based on a differential reading between the first and second temperature sensors.

6. The light detector of claim 1 , wherein the first light absorber includes a plurality of embedded slits or polarizer lines.

7. The light detector of claim 1 , wherein the plurality of first slits of the first light absorber are spaced a first distance apart, the first distance equal to a quarter of a wavelength of the selected first light.

8. The light detector of claim 1 , wherein a length of an outer edge of the first light absorber is equal to a long-end wavelength of the selected first light.

9. The light detector of claim 1 , wherein a distance between adjacent slits included in the plurality of first slits of the first light absorber is equal to a short-end wavelength of the selected first light.

10. The light detector of claim 1 , the detector further comprising:
a third light absorber configured to:
select third light from the incident light, and
absorb the selected third light; and

a fourth light absorber configured to:
select fourth light from the incident light, and
absorb the selected fourth light,

wherein each light absorber includes a post to thermally couple to the first temperature sensor.

11. The light detector of claim 1 , further comprising:
an encapsulation disposed on at least a portion of the first light absorber and including a transparent material.

12. The light detector of claim 1 , further comprising:
an encapsulation supporting at least the first and second light absorbers.

13. The light detector of claim 1 , further comprising:
a second temperature sensor thermally coupled to the second light absorber; and
a processor configured to calculate an angle of polarization of light absorbed by the first and second light absorbers based on at least information from the first and second temperature sensors.

14. The light detector of claim 1 , further comprising:
a reflector having a surface facing at least one of the first and second light absorbers and spaced a distance equal to a quarter of a wavelength of the selected first light or a wavelength of the selected second light.

15. The light detector of claim 14 , further comprising:
a second temperature sensor thermally coupled to the second light absorber,
wherein the reflector is thermally coupled to at least one of the first and second temperature sensors.

16. The light detector of claim 14 , further comprising:
one or more structures configured to support the reflector; and
an encapsulation, the encapsulation comprising a same material as the one or more structures.

17. The light detector of claim 1 , further comprising:
a first electrical insulator thermally coupled to the first light absorber and the first temperature sensor,
wherein the first electrical insulator electrically isolates the first light absorber from the second light absorber, and
further wherein the first temperature sensor thermally couples the first light absorber to the second light absorber.

18. The light detector of claim 1 , wherein the first and second light absorbers are included in a plurality of light absorbers, each light absorber is a mesh, and the plurality of light absorbers form a capacitive resonant mesh.

19. A method of detecting incident radiation, the method comprising:
applying a first voltage to a first light absorber included in a detector;
applying a second voltage to a second light absorber included in the detector;
selectively absorbing first light from the incident radiation using the first light absorber, the selective absorption of the first light based on one or more features of the first light absorber, the one or more features including at least one of a plurality of first slits, a first mesh, and a first plate absorber;
selectively absorbing second light from the incident radiation using the second light absorber, the selective absorption of the second light based on one or more second features of the second light absorber, the one or more second features including at least one of a plurality of second slits, a second mesh, and a second plate absorber;
measuring a first photocurrent from the first light absorber, the first photocurrent indicative of the selectively absorbed first light;
measuring a second photocurrent from the second light absorber, the second photocurrent indicative of the selectively absorbed second light; and
determining a polarization of the incident radiation based on the measured first and second photocurrents.

20. The method of claim 19 , wherein the second photocurrent is included in the first photocurrent, and further wherein the measurement of the first photocurrent and the measurement of the second photocurrent includes determining a differential reading between the first light absorber and the second light photocurrents.

Assignees

• Apple Inc

Inventors

• Kangas Miikka M
• Bishop Michael J
• Chen Robert
• Simon David I
• Sontag Iii Harold L
• Skidmore George Dee

Classifications

• G01J5/023

  Particular leg structure or construction or shape; Nanotubes · CPC title

• G01J5/0225 Primary

  Shape of the cavity itself or of elements contained in or suspended over the cavity · CPC title

• G01J2005/202

  Arrays · CPC title

• G01J5/20

  using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices · CPC title

• G01J5/0853

  having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid · CPC title