Method and system for managing light at an optical interface

• US 8,432,611 B1
• Filed: 02/12/2012
• Issued: 04/30/2013
• Est. Priority Date: 07/08/2006
• Status: Active Grant

• Current Assignee: Cirrex Systems, LLC
• Original Assignee: Cirrex Systems, LLC
• Inventors: Wach, Michael L.
• Primary Examiner(s): Amari, Alessandro
• Application Number:
  US13/371,440
• Time in Patent Office: 443 Days
• Field of Search: 359/581, 359586-589
• US Class Current: 359/587
• CPC Class Codes: A61B 18/203 applying laser energy to the outside of the body
• CPC Class Codes: A61B 18/28 for heating a thermal probe or absorber
• CPC Class Codes: A61B 2018/00452 Skin
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0086 using infrared radiation
• CPC Class Codes: G01N 21/35 using infrared light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/3563 for analysing solids; Preparation of samples therefor
• CPC Class Codes: G01N 21/6402 Atomic fluorescence; Laser induced fluorescence
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: G02B 5/288 comprising at least one thin film resonant cavity, e.g. in bandpass filters
• CPC Class Codes: G02B 5/289 Rugate filters
• CPC Class Codes: G02B 6/4207 with optical elements reducing the sensitivity to optical feedback anti-reflection devices specially adapted for lasers, see H01S3/0064

Abstract

An interface between two different optical materials can comprise a stack of thin film layers that manage light incident on that interface. One of the optical materials can have a first composition and a first refractive index, while the other optical material can have a second composition and a second refractive index. The stack can comprise thin film layers of the first optical material interleaved between thin film layers of the second optical material. The layers of the stack can be configured to provide the stack with an aggregate composition of at least one of the optical materials that progressively varies from one end of the stack to the other end. To provide the progressive variation in composition, the layers of one of the optical materials can have a progressively increased thickness across the stack, or can progressively increase in number, for example.

Claims

1. An optical filter comprising:

a series of thin film optical interfaces, each formed between a respective high index thin film layer and a respective low index thin film layer; and

a respective series of transition layers of alternating refractive indices disposed at each thin film optical interface in the series of thin film optical interfaces, each respective series of transition layers comprising;

high index transition layers disposed in one of the respective low index thin film layers; and

low index transition layers disposed in one of the respective high index thin film layers, and

wherein the high index thin film layers and low index thin film layers and the series of transition layers of alternating refractive indices collectively provide a sinusoidal variation in refractive index or collectively provide a refractive index profile having the form of a square wave with rounded corners.

2. The optical filter of claim 1, wherein the high index transition layers and the high index thin film layers have common compositions.

3. The optical filter of claim 1, wherein one or more of the high index transition layers and one or more of the high index thin film layers have a common composition.

4. The optical filter of claim 1, wherein a particular thin film optical interface is formed between a particular low index thin film layer having a first refractive index and a particular high index thin film layer having a second refractive index,

wherein the series of transition layers disposed at the particular thin film optical interface comprises high index transition layers of the second refractive index disposed in the particular low index thin film layer.

5. The optical filter of claim 1, wherein a particular thin film optical interface is formed between a particular low index thin film layer having a first refractive index and a particular high index thin film layer having a second refractive index,

wherein the series of transition layers disposed at the particular thin film optical interface comprises low index transition layers of the first refractive index disposed in the particular high index thin film layer.

6. The optical filter of claim 1, comprising low index transition layers no thicker than about ten nanometers and high index transition layers no thicker than about ten nanometers.

7. The optical filter of claim 1, wherein one or more of the low index transition layers and one or more of the low index thin film layers have a common composition.

8. The optical filter of claim 1, wherein one of the low index transition layers and one of the low index thin film layers comprise a first refractive index, and wherein one of the high index transition layers and one of the high index thin film layers comprise a second refractive index that is substantially higher than the first refractive index.

9. The optical filter of claim 1, wherein each one of the low index transition layers of at least one of the series of transition layers of alternating refractive indices is thinner than the previous low index transition layer of the series.

10. The optical filter of claim 1, wherein each one of the high index transition layers of at least one of the series of transition layers of alternating refractive indices is thinner than the previous high index transition layer of the series.

11. An optical filter comprising:

high index thin film layers interleaved with low index thin film layers to form a periodic series of optical interfaces; and

a respective system of alternating refractive index transition layers disposed at each of the optical interfaces,

each system of alternating refractive index transition layers comprising;

high index transition layers disposed in one of the interleaved low index thin film layers; and

low index transition layers disposed in one of the interleaved high index thin film layers, and

wherein the high index thin film layers interleaved with low index thin film layers and the systems of alternating refractive index transition layers collectively provide a sinusoidal variation in refractive index or collectively provide a refractive index profile having the form of a square wave with rounded corners.

12. The optical filter of claim 11, wherein each of the high index transition layers has a respective thickness that is less than ten nanometers, and

wherein each of the low index transition layers has a respective thickness that is less than ten nanometers.

13. The optical filter of claim 11, wherein each system of alternating refractive index layers comprises progressively thinner layers.

14. The optical filter of claim 11, wherein each respective one of the high index transition layers of one of the systems of alternating refractive index transition layers is thinner than the previous respective one of the high index transition layers in the system, such that the high index transition layers of the system are progressively thinner.

15. The optical filter of claim 11, wherein each respective one of the low index transition layers of one of the systems of alternating refractive index transition layers is thinner than the previous respective one of the low index transition layers in the system, such that the system comprises progressively thinner low index transition layers.

16. An optical filter comprising:

a periodic arrangement of optical interfaces, individually operative to transmit and reflect incident light and collectively operative to filter light via optical interference,

wherein each of the optical interfaces is formed between two respective layers of optical materials having contrasting refractive indices, with a respective series of transition layers of contrasting refractive index extending across each of the optical interfaces,

wherein each respective series of transition layers comprises;

a first plurality of transition layers disposed in a first of the two respective layers of optical materials; and

a second plurality of transition layers disposed in a second of the two respective layers of optical materials, and

wherein the layers of optical materials having contrasting refractive indices and series of transition layers of contrasting refractive index collectively provide a sinusoidal variation in refractive index or collectively provide a refractive index profile in the form of a square wave with rounded corners.

17. The optical filter of claim 16, wherein each respective series of transition layers is periodic.

18. The optical filter of claim 16, wherein the first plurality of transition layers and the second of the two respective layers have substantially common refractive indices, and

wherein the second plurality of transition layers and the first of the two respective layers have substantially common refractive indices.

19. The optical filter of claim 16, wherein the first plurality of transition layers and the second of the two respective layers have substantially common composition, and

wherein the second plurality of transition layers and the first of the two respective layers have substantially common composition.

20. The optical filter of claim 16, wherein each of the first plurality of transition layers disposed in the first of the two respective layers of optical materials is less than about ten nanometers in thickness.