Integrated magneto-optic modulator/compensator system, methods of making, and methods of using the same

Patent metadata

Field	Value
Publication number	US-9423635-B1
Application number	US-201414169280-A
Country	US
Kind code	B1
Filing date	Jan 31, 2014
Priority date	Jan 31, 2014
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

Described herein is an integrated Faraday modulator and Faraday compensator (IFMC) system. Further described are methods of making an IFMC system, methods of customizing an IFMC system for a specific application, and methods of optimizing an IFMC system for a specific application. Further described is a robust 3D Finite Element Model (FEM) for designing and optimizing an IFMC system. Further described are optical instruments comprising an integrated Faraday modulator and Faraday compensator requiring only one optical crystal.

First claim

What is claimed is:

1. An integrated Faraday modulator/compensator (IFMC) system comprising:
an optical material;
at least one AC magnetic field source disposed in a first position in proximity to the optical material, the AC magnetic field source being configured to generate a first magnetic field; and,
at least one DC magnetic field source disposed in a second position in proximity to the optical material, the DC magnetic field source being configured to generate a second magnetic field;
the first position and the second position being configured to cause the first magnetic field and the second magnetic field to be superimposed on the optical material.

2. The IFMC system of claim 1 , wherein the optical material comprises a single optical crystal.

3. The IFMC system of claim 1 , wherein superposition of the first and second magnetic fields within the optical material causes rotational modulation and compensation of a light beam's electric field passing through the optical material.

4. The IFMC system of claim 1 , wherein the optical material is aligned on a first axis, the at least one AC magnetic field source is aligned on a second axis, and the at least one DC magnetic field source is aligned on a third axis; wherein the first, second, and third axes are in a parallel, and spaced-apart, alignment.

5. The IFMC system of claim 1 , wherein one or more spaces are defined between the optical material and the AC magnetic field source or the DC magnetic field source.

6. The IFMC system of claim 1 , wherein orientation of at least one of the first magnetic field and the second magnetic field is adjustable with respect to the each other and to the optical material.

7. The IFMC system of claim 1 , wherein each of the AC and DC magnetic field sources is comprised of an inductive coil circumferentially surrounding a ferromagnetic core; and,
wherein the magnitude of the first magnetic field and the second magnetic field is dependent on the distance from each AC magnetic field source and DC magnetic field source as well as the magnitude of a current driving each inductive coil, while the direction of each magnetic field is perpendicular to a plane formed by the intersection of the current and separation vectors using Equation 4:

B
⁡

(
r
)

=

μ
0

4
⁢
π

⁢

∮

I
×
R

R
3

⁢

ⅆ

r
0

;

wherein bolded terms represent vector quantities, B(r) is the magnetic field at any point in space a distance r from the origin, no is the permeability of free space (4π×10 −2 N/A 2 ), I is the current, R is the vector directed from the source point to r, and dr 0 is an element of length along the current path.

8. The IFMC system of claim 1 , wherein the first magnetic field is generated by an AC current from a first power source, and the second magnetic field is generated by a DC current from a second power source.

9. The IFMC system of claim 1 , wherein each of the AC and DC magnetic field sources is comprised of an inductive coil circumferentially surrounding a ferromagnetic core; wherein each the ferromagnetic cores defines an axis that is parallel to, and annularly spaced at about 90° intervals around, an axis defined by the optical material.

10. The IFMC system of claim 1 , wherein the IFMC system has a modulation depth of about 1° and a maximum compensation depth of about 0.0632°.

11. The IFMC system of claim 1 , wherein the AC magnetic field source comprises a high-powered resonant circuit having one or more inductive coils and a magnetic core.

12. The IFMC system of claim 1 , wherein the AC magnetic field source comprises a ferromagnetic core and an electrically driven coil.

13. The IFMC system of claim 12 , wherein different size, shape, and/or inductances of the coil provides a desire operational range of rotations based on the maximum voltage supplied to the AC magnetic field source.

14. The IFMC system of claim 1 , wherein the AC magnetic field source comprises a vibrationally mounted permanent magnet.

15. The IFMC system of claim 1 , wherein the AC magnetic field source comprises at least one 100 mH inductor.

16. The IFMC system of claim 1 , wherein the DC magnetic field source is comprised of a low-powered DC circuit having one or more inductive coils and a magnetic core.

17. The IFMC system of claim 1 , wherein the DC magnetic field source comprises a ferromagnetic core and an electrically driven coil.

18. The IFMC system of claim 17 , wherein different size, shape, and/or inductances of the coil provides a desire operational range of rotations based on the maximum voltage supplied to the DC magnetic field source.

19. The IFMC system of claim 1 , wherein two or more AC magnetic field sources are connected in series such that current flows in the same direction around each coil, producing a collectively maximized axial component of the magnetic field along the optical material, and achieving an effective Faraday modulation to light passing through the optical material.

20. The IFMC system of claim 1 , wherein the optical material comprises a terbium-doped glass (TDG) material; a terbium gallium garnet (TGG) material; or, an yttrium iron garnet (YIG) material.

21. The IFMC system of claim 1 , wherein the optical material has a length-to-diameter aspect ratio of about 2.5.

22. The IFMC system of claim 1 , wherein the optical material has a length of about 13.5 mm and a diameter of about 5.4 mm.

23. The (IFMC) component apparatus of claim 1 , wherein
the first power source is disposed outside a modular housing and configured to supply an AC current to the AC magnetic field source; and,
the second power source disposed outside the modular housing and configured to supply a DC current to the DC magnetic field source.

24. The IFMC component apparatus of claim 23 , further including a polarizer disposed outside the modular housing and configured to supply polarized light through the optical material.

25. The IFMC component apparatus of claim 23 , further including an analyzer disposed outside the modular housing and configured to receive modulated and compensate light from the IFMC system.

26. The IFMC component apparatus of claim 23 , further including a detector disposed outside the modular housing and

Assignees

• Univ Toledo

Inventors

• Cameron Brent D
• Clarke Brandon W

Classifications

• G01N21/21

  Polarisation-affecting properties (G01N21/19 takes precedence) · CPC title

• G02F1/09 Primary

  based on magneto-optical elements, e.g. exhibiting Faraday effect · CPC title

• G02F1/092

  Operation of the cell; Circuit arrangements · CPC title

• A61B5/14532 Primary

  for measuring glucose, e.g. by tissue impedance measurement · CPC title

• G01N2201/067

  Electro-optic, magneto-optic, acousto-optic elements · CPC title