Polarizing lamp

1. An apparatus comprising:

a polarizing lamp comprising:

a polarization beam splitter;

a metallic grating reflector having metallic gratings with a trapezoidal profile; and

an unpolarized light source positioned between the polarization beam splitter and the metallic grating reflector.

2. The apparatus of claim 1 in which the trapezoidal profile comprises a top width in a range between 50 nm to 70 nm, and a bottom width between 60 nm to 90 nm.

3. The apparatus of claim 1 in which the trapezoidal profile comprises a height in a range between 110 nm to 140 nm.

4. The apparatus of claim 1 in which the metallic gratings have a period that is less than a wavelength of the light generated by the unpolarized light source.

5. The apparatus of claim 1 in which the metallic gratings comprise multi-order diffraction gratings.

6. The apparatus of claim 1 in which the polarization beam splitter comprises a broadband wide-angle polarization beam splitter.

7. The apparatus of claim 1 in which the light source comprises a light tube.

8. The apparatus of claim 7 in which the gratings extend along a direction at an angle in a range between 40 to 50 degrees relative to a lengthwise direction of the light tube.

9. The apparatus of claim 1 in which the polarizing beam splitter reflects transverse electric waves and passes transverse magnetic waves.

10. The apparatus of claim 1 in which the metallic grating reflector has a shape corresponding to a parabolic cylinder, a circular cylinder, a rectangular cylinder, a square cylinder, a triangular cylinder, a trapezoid cylinder, or any combination of the above.

11. The apparatus of claim 1 in which the polarization beam splitter comprises at least one of prisms, a multi-layered film, a dielectric grating, or a wire-grid structure.

12. The apparatus of claim 1 in which the polarization beam splitter has a shape that corresponds to at least one of a rectangular plane, a portion of a parabolic cylinder, a portion of a circular cylinder, a portion of a rectangular cylinder, a portion of a square cylinder, a portion of a triangular cylinder, or a portion of a trapezoid cylinder.

13. The apparatus of claim 1 in which the metallic grating reflector comprises at least one of metallic surface gratings, metallic coated surface gratings, metallic coated multi-layers gratings, or multi-layer volume gratings.

14. The apparatus of claim 1 in which the metallic grating reflector comprises multi-layer volume gratings having multi-periods composed of materials alternately arranged to have different refractive indices.

15. A display comprising:

a plurality of pixels;

a polarizing lamp to illuminate the pixels, the polarizing lamp comprising:

a polarization beam splitter;

a parabolic metallic grating reflector having metallic gratings with a trapezoidal profile; and

an unpolarized light tube positioned between the polarization beam splitter and the parabolic metallic grating reflector.

16. The display of claim 15 in which the trapezoidal profile comprises a top width in a range between 50 nm to 70 nm, a bottom width between 60 nm to 90 nm, and a height in a range between 110 nm to 140 nm.

17. A method comprising:

emitting light waves from an unpolarized light source;

repeatedly reflecting portions of the light waves between a metallic grating reflector and a polarization beam splitter, the metallic gratings having a trapezoidal profile; and

passing portions of the light waves having a particular polarization through the polarization beam splitter.

18. The method of claim 17 , comprising reflecting transverse electric waves from the polarization beam splitter and passing transverse magnetic waves through the polarization beam splitter.

19. The method of claim 17 , wherein the metallic grating reflector converts transverse electric waves into elliptically polarized waves.

20. The method of claim 17 , comprising illuminating pixels of a display panel operating on light waves that pass the polarization beam splitter.