Horizontally-scalable microcavity-enhanced raman scattering integrated platform for multigas chemical analysis

1. A horizontally-scaled Raman sensor for chemical analysis of a fluid, where the concentration of multiple chemical species of interest in a sample can be detected simultaneously, said sensor comprising:

a first high-reflector micromirror having a substantially planar surface;

an array of second high-reflector micromirrors each having a curved concave surface,

wherein a longitudinal extent of said substantially planar surface is substantially parallel to a longitudinal extent of said curved surface,

a channel formed between said first high-reflector micromirror and said array of second high-reflector micromirrors, said sample following a path of travel through said channel and along said substantially planar and curved surfaces;

an array of ultrahigh finesse microcavities formed between said substantially planar surface and each concave micromirror, said array of microcavities each having a microcavity length equal to the distance between said substantially planar surface of said first high-reflector micromirror and said curved surface of said each second high-reflector micromirror;

an excitation laser positioned to emit a light beam incident upon said first high-reflector micromirror and said each second high-reflector micromirror;

a Raman emission signal detector positioned to receive an array of Raman shifted emission signals in order to detect a concentration of a species of interest within said sample that is disposed between said substantially planar surface of said first high-reflector micromirror and said curved surface of said array of second high-reflector micromirrors, wherein said microcavities enhance a magnitude of said Raman shifted emission signals,

said first high-reflector micromirror and said each second high-reflector micromirror each exhibiting a high reflectivity of greater than about 99.9% both at a frequency of said light beam emitted by said excitation laser and at a frequency of a Raman-shifted signal of said species of interest,

whereby at least one of said array of second high-reflector micromirrors is resonant with a frequency of said excitation laser frequency and doubly-resonant with said Raman-shifted signal of said species of interest,

whereby said species of interest can be detected at concentrations of parts-per-million or less.

2. A sensor as in claim 1 , wherein said first high-reflector micromirror is a semiconductor mirror.

3. A sensor as in claim 2 , wherein said first high-reflector micromirror and said each second high-reflector micromirror are dielectrically coated.

4. A sensor as in claim 2 , further comprising gain layers, including quantum wells or quantum dots, are present within said semiconductor micromirror.

5. A sensor as in claim 1 , further comprising a laser focusing component positioned between said excitation laser and said first high-reflector micromirror to focus or mode match said light through said microcavities.

6. A sensor as in claim 5 , wherein said laser focusing component is a microlens array having a curvature that matches said first and second micromirrors to said microlens array.

7. A sensor as in claim 1 , further comprising a secondary filter that removes any residual laser pump light, said secondary filter positioned between said Raman emission signal detector and said first and second micromirrors.

8. A sensor as in claim 1 , wherein said microcavity length is tunable piezoelectrically.

9. A sensor as in claim 1 , wherein said sample is selected from the group consisting of a gas and a liquid.

10. A sensor as in claim 1 , wherein said microcavity length is about 1 μm to about 10 μm.

11. A sensor as in claim 1 , wherein said excitation laser is an array of vertical-external-cavity surface-emitting lasers.

12. A sensor as in claim 1 , wherein said excitation laser is a non-resonant laser.

13. A sensor as in claim 1 , wherein said array of second high-reflector microcavities includes about 10,000-1,000,000 microcavities on a 1 cm 2 area.

14. A sensor as in claim 1 , wherein said Raman emission signal detector includes image processing that yields a signal with magnitude that scales with the number of microcavities in said array of microcavities.

15. A sensor as in claim 1 , wherein said array of second high-reflector micromirrors are disposed directly adjacent to one another, such that said array of microcavities are adjacent to one another also.

16. A sensor as in claim 1 , wherein a radius of curvature of said curved concave surface of said each second high-reflector micromirror is smaller than a distance between adjacent curved concaved surfaces.

17. A sensor as in claim 1 , wherein said Raman emission signal detector is a charge-coupled device.

18. A horizontally-scaled Raman sensor for chemical analysis of a fluid, where the concentration of multiple chemical species of interest in a gas or liquid sample can be detected simultaneously, said sensor comprising:

a first high-reflector semiconductor micromirror having a substantially planar surface;

an array of second high-reflector micromirrors each having a curved concave surface, wherein said first high-reflector micromirror and said each second high-reflector micromirror are dielectrically coated,

wherein a longitudinal extent of said substantially planar surface is substantially parallel to a longitudinal extent of said curved surface,

wherein said array of second high-reflector microcavities includes about 10,000-1,000,000 microcavities on an approximately 1 cm 2 area,

wherein a radius of curvature of said curved concave surface of said each second high-reflector micromirror is smaller than a distance between adjacent curved concaved surfaces;

a channel formed between said first high-reflector micromirror and said array of second high-reflector micromirrors, said sample following a path of travel through said channel and along said substantially planar and curved surfaces;

an array of ultrahigh finesse microcavities formed between said substantially planar surface and each concave micromirror, said array of microcavities each having a microcavity length equal to the distance between said substantially planar surface of said first high-reflector micromirror and said curved surface of said each second high-reflector micromirror,

wherein said microcavity length is tunable piezoelectrically, wherein said microcavity length is about 1 μm to about 10 μm,

wherein said array of second high-reflector micromirrors are disposed directly adjacent to one another, such that said array of microcavities are adjacent to one another also,

an excitation laser positioned to emit a light beam incident upon said first high-reflector micromirror and said each second high-reflector micromirror, wherein said excitation laser is a non-resonant laser or an array of vertical-external-cavity surface-emitting lasers;

a laser focusing component positioned between said excitation laser and said first high-reflector micromirror to focus or mode match said light through said microcavities, wherein said laser focusing component is a microlens array having a curvature that matches said first and second micromirrors to said microlens array;

a charge-coupled device positioned to receive an array of Raman shifted emission signals in order to detect a concentration of a species of interest within said sample that is disposed between said substantially planar surface of said first high-reflector micromirror and said curved surface of said array of second high-reflector micromirrors, wherein said microcavities enhance a magnitude of said Raman shifted emission signals,

wherein said charge-coupled device includes image processing that yields a signal with magnitude that scales with the number of microcavities in said array of microcavities; and

a secondary filter that removes any residual laser pump light, said secondary filter positioned between said charge-coupled device and said first and second micromirrors,

said first high-reflector micromirror and said each second high-reflector micromirror each exhibiting a high reflectivity of greater than about 99.9% both at a frequency of said light beam emitted by said excitation laser and at a frequency of a Raman-shifted signal of said species of interest;

whereby at least one of said array of second high-reflector micromirrors is resonant with a frequency of said excitation laser frequency and doubly-resonant with said Raman-shifted signal of said species of interest,

whereby said species of interest can be detected at concentrations of parts-per-million or less.