Photonic crystal interferometer

1. A sensor apparatus comprising:

a photonic crystal structure optically coupled to a laser, said structure comprising:

a beam splitter;

an interferometer having a reference arm and a sensor arm, said reference arm and said sensor arm optically coupled to said beam splitter;

a first output configured to be optically coupled to a bright port photodetector and said beam splitter;

a second output configured to be optically coupled to a dark port photodetector and said beam splitter; and

a photonic crystal mirror optically coupled to said photonic crystal structure, said photonic crystal mirror positioned to reflect light propagating in a first direction of said reference arm into a direction generally opposite said first direction in said reference arm and reflect light propagating in a second direction of said sensor arm into a direction generally opposite said second direction in said sensor arm.

2. The sensor apparatus as set forth in claim 1 , wherein said interferometer is a double pass interferometer.

3. The sensor apparatus as set forth in claim 2 , wherein said double pass interferometer comprises a Michelson interferometer.

4. The sensor apparatus as set forth in claim 1 , wherein the presence of light at said second output indicates the presence of molecules in said sensor arm.

5. The sensor apparatus as set forth in claim 1 , further comprising a DC phase-shifter in said reference arm.

6. The sensor apparatus as set forth in claim 1 , further comprising an AC phase-shifter in said sensor arm.

7. The sensor apparatus as set forth in claim 1 , wherein said photonic crystal mirror comprises a photonic crystal Bragg mirror.

8. The sensor apparatus as set forth in claim 1 , wherein said reference arm is passivated.

9. The sensor apparatus as set forth in claim 1 , wherein said photonic crystal structure comprises III-V semiconductor materials.

10. The sensor apparatus as set forth in claim 1 , wherein said photonic crystal structure comprises voids.

11. The sensor apparatus as set forth in claim 10 , wherein said voids are formed by nanoimprinting a pattern.

12. A method for sensing comprising:

providing a laser input to a photonic crystal structure having a sensed medium region;

supplying an analyte in said sensed medium region;

transmitting said laser input through said sensed medium;

reflecting said laser input off of a photonic crystal mirror to transmit said laser input back through said sensed medium and into a first output and a second output of said photonic crystal structure; and

detecting said analyte by measuring said first output and said second output of said photonic crystal structure.

13. The method as set forth in claim 12 wherein said first output and said second output comprise light.

14. The method of claim 13 , wherein said first output emits from a bright port and said second output emits from a dark port.

15. The method of claim 14 , wherein said bright port is configured to be coupled to a first photodetector and said dark port is configured to be coupled to a second photodetector.

16. A sensor apparatus comprising:

means for generating a laser input to a photonic crystal structure having a sensed medium region containing an analyte;

means for transmitting said laser input through said sensed mediurm

means for reflecting said laser input back through said sensed medium region into a first output and a second output of said photonic crystal structure; and

means for detecting said analyte by measuring said first output and said second output of said photonic crystal structure.

17. The sensor apparatus as set forth in claim 16 wherein said detecting means further comprise a bright port configured to be coupled to a first photodetector and a dark port configured to be coupled to a second photodetector for measuring said first and second outputs of said photonic crystal structure.