Optical micro-spectrometer
An optical spectrometer having a multi-wafer structure. The structure may be fabricated with MEMS technology. The spectrometer may be integrated with a fluid analyzer. A reflective grating such as a diffraction or holographic grating situated on the circumference of a Rowland circle along with a point of light emission and a detector may be a configuration of the spectrometer. Some configurations may use an external light source where the light may be optically conveyed to the point of emission on the circle. There may be a Raman configuration where an interaction of light with a sample or an interactive film of a channel in a fluid analyzer is the point of light emission for the spectrometer. In some configurations of the spectrometer, the grating and/or the film may be reflective or transmissive.
1. An optical spectrometer comprising:
a first wafer;
a second wafer having a channel situated on the first wafer, the channel having a first portion and a second portion;
a light source situated at a first end of the first portion of the channel;
a reflector situated at a second end of the first portion of the channel and a first end of the second portion of the channel; and
a detector array situated at a second end of the second portion of the channel; and
wherein the light source, reflector and detector array are situated about a circumference of a circle in a plane; and
the light source is a micro discharge device.
2. The spectrometer of claim 1 , wherein the reflector is a concave diffraction grating, a holographic concave reflective grating, or a focusing transmission grating.
3. The spectrometer of claim 1 , wherein the circle is a Rowland circle.
4. The spectrometer of claim 1 , wherein:
the first portion of the channel and the second portion of the channel are connected to each other; and
a fluid flow channel has an inlet situated proximate to the light source, a path through the first portion of the channel and the second portion of the channel, and an outlet situated proximate to the detector array.
5. The spectrometer of claim 1 , wherein the detector array is a photo-detector array.
6. The spectrometer of claim 1 , wherein the first and second wafers and the first and second channels may be fabricated with MEMS (micromachined electro mechanical system) technology.
7. The spectrometer of claim 2 , wherein the grating comprises a set of grating grooves or a holographic grating having dimensions compatible with a spectrum or spectrums to be observed within the spectrometer.
8. A spectrometer comprising:
a first wafer;
a detector situated on the first wafer;
a second wafer situated on the first wafer, having a first opening about the detector, and having a light source;
a third wafer, situated on the second wafer, having a second opening approximately aligned with the first opening, and having a channel intersecting the first and second openings; and
a fourth wafer situated on the third wafer, and having a reflector-grating situated proximate to the second opening; and
wherein the light source is a micro discharge device.
9. The spectrometer of claim 8 , wherein a light path is available from the light source to the reflector-grating, and from the reflector-grating to the detector.
10. The spectrometer of claim 8 , wherein:
the detector is a photo-detector.
11. The spectrometer of claim 8 , wherein the light source, the reflector-grating and the detector are situated proximate to a circumference of a circle.
12. The spectrometer of claim 8 , wherein the light source is an end of an optical fiber having another end coupled to a source of light.
13. A spectrometer comprising:
a first wafer;
a detector situated on the first wafer;
a second wafer situated on the first wafer, having a first opening about the detector, and having a light source;
a third wafer, situated on the second wafer, having a second opening approximately aligned with the first opening, and having a channel intersecting the first and second openings; and
a fourth wafer situated on the third wafer, and having a reflector-grating situated proximate to the second opening; and
wherein the light source is a micro discharge device; and
the detector is a photo-detector.