Gap distributed Bragg reflectors

• US 9,912,121 B2
• Filed: 05/09/2016
• Issued: 03/06/2018
• Est. Priority Date: 08/25/2011
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Wunderer, Thomas, Chua, Christopher L., Krusor, Brent S., Johnson, Noble M.
• Primary Examiner(s): Gray, Sunghee Y
• Application Number:
  US15/149,595
• Publication Number:
  US 20160254648A1
• Time in Patent Office: 666 Days
• Field of Search: 372 5011, 372 46014, 372 99, 257E33069, 438 8
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01N 21/17 Systems in which incident light is modified in accordance with the properties of the material investigated where the material investigated is optically excited causing a change in wavelength of the incident light G01N21/63
• CPC Class Codes: G01N 21/41 Refractivity; Phase-affecting properties, e.g. optical path length G01N21/21 takes precedence
• CPC Class Codes: G01N 2201/0635 Structured illumination, e.g. with grating
• CPC Class Codes: G01N 2201/08 Optical fibres; light guides
• CPC Class Codes: G02B 5/0816 Multilayer mirrors, i.e. having two or more reflecting layers G02B5/0883, G02B5/0891 take precedence
• CPC Class Codes: G02B 5/085 at least one of the reflecting layers comprising metal
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18341 Intra-cavity contacts
• CPC Class Codes: H01S 5/18363 comprising air layers
• CPC Class Codes: H01S 5/18369 based on dielectric materials
• CPC Class Codes: H01S 5/18377 comprising layers of different kind of materials, e.g. combinations of semiconducting with dielectric or metallic layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A device includes one or more reflector components. Each reflector component comprises layer pairs of epitaxially grown reflective layers and layers of a non-epitaxial material, such as air. Vias extend through at least some of the layers of the reflector components. The device may include a light emitting layer.

Claims

1. A sensor comprising:

a plurality of layer pairs, each layer pair comprising;

a reflective layer; and

an interstitial gap, each reflective layer having a first thickness and a first index of refraction and each interstitial gap having a second thickness and a second index of refraction, the first and second thicknesses and the first and second indices of refraction selected to reflect incident light traveling along a first direction, the layer pairs arranged such that each interstitial gap is disposed between two reflective layers, the plurality of layer pairs forming a distributed Bragg reflector (DBR); and

at least one opening configured to allow entry of an analyte into the interstitial gaps within the DBR.

2. The sensor of claim 1, wherein the sensor is a monolithic structure that includes a light emitting device configured to generate light that is directed toward by the DBR.

3. The sensor of claim 2, further comprising an additional DBR, the light emitting device disposed between the DBR and the additional DBR.

4. The sensor of claim 1, wherein the sensor is a monolithic structure that includes a photodetector configured to detect light reflected or transmitted by the DBR.

5. The sensor of claim 1, wherein the sensor is a monolithic structure that includes an additional DBR and a light emitting device disposed between the DBR and the additional DBR.

6. The sensor of claim 5, wherein the light emitting device comprises a vertical cavity surface emitting laser.

7. The sensor of claim 1, wherein air or a vacuum is present within the interstitial gaps before entry of the analyte.

8. The sensor of claim 1, wherein the reflective layers comprise GaN.

9. The sensor of claim 1, wherein the reflective layers are epitaxial layers.

10. A system comprising:

a sensor, comprising;

a plurality of layer pairs, each layer pair comprising;

a reflective layer; and

an interstitial gap, each reflective layer having a first thickness and a first index of refraction and each interstitial gap having a second thickness and a second index of refraction, the first and second thicknesses and the first and second indices of refraction selected to reflect incident light traveling along a first direction, the layer pairs arranged such that each interstitial gap is disposed between two reflective layers, the layer pairs forming a distributed Bragg reflector (DBR); and

at least one opening configured to allow entry of an analyte into the interstitial gaps;

a light emitting device configured to generate light directed toward the DBR; and

a photodetector configured to sense light reflected or transmitted by the DBR and to generate a signal based on the sensed light.

11. The system of claim 10, further comprising a processor configured to receive the signal and to detect a presence of the analyte based on the signal.

12. The system of claim 11, wherein the processor is configured to identify the analyte based on the signal.

13. The system of claim 11, wherein the processor is configured to determine a characteristic of the analyte based on the signal.

14. A method comprising:

exposing a sensor to an analyte, the sensor including;

a plurality of layer pairs, each layer pair comprising;

an interstitial gap, each reflective layer having a first thickness and a first index of refraction and each interstitial gap having a second thickness and a second index of refraction, the first and second thicknesses and the first and second indices of refraction selected to reflect incident light traveling along a first direction, the layer pairs arranged such that each interstitial gap is disposed between two reflective layers, the layer pairs forming a distributed Bragg reflector (DBR); and

at least one opening fluidically coupled to the interstitial gaps;

allowing the analyte to enter the interstitial gaps through the opening, entry of the analyte changing optical properties of the DBR;

sensing light transmitted or reflected by the DBR; and

detecting a presence of the analyte based on the sensed light.

15. The method of claim 14, further comprising identifying the analyte based on the sensed light.

16. The method of claim 15, further comprising determining at least one characteristic of the analyte based on the sensed light.

17. The method of claim 16, wherein the at least one characteristic comprises one or more of temperature, pressure and concentration of the analyte.

18. The method of claim 14, wherein the sensed light indicates a change in refractive index of the sensor when the analyte is present in the interstial gaps.

19. The method of claim 14, further comprising generating light directed toward the DBR.