Ultra-miniature spatial heterodyne spectrometer
Ultra-miniature spatial heterodyne spectrometers (SHSs) are presented. Ultra-miniature SHSs in accordance with the invention, comprise a beam-splitter and gratings configured to generate a fringe pattern for spectroscopic detection. Many embodiments include input optics and a sensor and are configured in a way to omit collimating optics and imaging optics from the SHS. Compared to conventional SHSs known in the art, the present invention enables fewer parts, significantly smaller and lighter SHSs, are more efficient and robust, and require less maintenance. Many embodiments are field-deployable, in that such embodiments can be deployed for hand held use in real-world or remote activities outside of research or diagnostic facilities.
1 . A field-deployable device for performing spectroscopy comprising:
input optics;
a spatial heterodyne spectrometer (SHS) comprising a beam-splitter, a first grating, and a second grating, wherein the beam-splitter, the first grating, and the second grating form a 90° angle with the beam-splitter at the vertex of the angle, and wherein the beam-splitter is configured to split the incoming light to the first grating and the second grating; and
a spectroscopy sensor configured to acquire a fringe pattern generated by the SHS; and
a housing assembly forming an aperture and holding the input optics, the SHS, and the spectroscopy sensor;
wherein the aperture, the input optics, the SHS, and the spectroscopy sensor are in optical alignment, such that incoming light passes through the aperture into the input optics;
wherein the input optics are configured to direct light to the SHS; and
wherein a position of the aperture, a position of the first grating, and a position of the second grating are configured such that a fringe localization plane (FLP) is located proximally toward the aperture from the first grating and the second grating.
2 . The field-deployable device for performing spectroscopy of claim 1 , further comprising a first field widened prism and a second field widened prism, wherein the first field widened prism is located between the beam-splitter and the first grating and the second field widened prism is located between the beam-splitter and the second grating.
3 . The field-deployable device for performing spectroscopy of claim 2 , wherein a position of the first field widened prism and a position of the second field widened prism are configured such that the FLP is located proximally toward the aperture from the first grating and the second grating.
4 . The field-deployable device for performing spectroscopy of claim 3 , wherein the first field widened prism forms a first angle α with an edge of the beam-splitter and an edge of the first field widened prism proximal to the beam-splitter; wherein the second field widened prism forms a second angle α with an edge of the beam-splitter and an edge of the second field widened prism proximal to the beam-splitter, and wherein the first angle α and the second angle α are configured such that the FLP is located proximally toward the aperture from the first grating and the second grating.
5 . The field-deployable device for performing spectroscopy of claim 1 , wherein the first grating is tilted to form a first angle β between the first grating and a path of light directed toward the first grating; wherein the second grating is tilted to form a second angle β between the second grating and a path of light directed toward the second grating; and wherein the first angle β and the second angle β are configured such that the FLP is located proximally toward the aperture from the first grating and the second grating.
6 . The field-deployable device for performing spectroscopy of claim 1 , wherein the housing assembly comprises a frame and barrel assembly.
7 . The field-deployable device for performing spectroscopy of claim 1 further comprising a bandpass filter and an imaging sensor; wherein the incoming light passes intercepts the bandpass filter, wherein specific wavelengths of the intercepted light are deflected toward the input optics; wherein the remaining wavelengths of light pass through the bandpass filter and impinge on the imaging sensor.
8 . The field-deployable device for performing spectroscopy of claim 7 , wherein the housing assembly further holds the bandpass filter and the imaging sensor.
9 . The field-deployable device for performing spectroscopy of claim 1 , wherein the field-deployable device has a mass of less than 500 grams.
10 . The field-deployable device for performing spectroscopy of claim 1 , wherein the input optics are selected from a telescope, a microscope, and a coupled optical fiber system.
11 . A method of using a field-deployable spectroscopy device comprising:
obtaining a light emission from a sample using a field-deployable device for performing spectroscopy of claim 1 , wherein the light emission passes through the input optics into the SHS to image a fringe pattern on the spectroscopy sensor; and
analyzing the fringe pattern to identify a component within the sample.
12 . The method of claim 11 , further comprising obtaining a sample.
13 . The method of claim 12 , wherein the sample is a biological sample.
14 . The method of claim 13 , wherein the biological sample is obtained from at least one of saliva, mucus, blood, urine, fecal, skin, and tissue.
15 . The method of claim 12 , wherein the sample is an environmental sample selected from a water sample, soil sample, rock sample, air sample.
16 . The method of claim 12 , wherein the sample is obtained from a high-touch area.
17 . The method of claim 12 , wherein the sample is a pharmaceutical.
18 . The method of claim 11 , further comprising illuminating the sample.
19 . The field-deployable device for performing spectroscopy of claim 1 , wherein the input optics are configured to direct light to the SHS without collimation.
20 . The field-deployable device for performing spectroscopy of claim 19 , wherein the spectroscopy sensor comprises a camera without lenses and without filters, and wherein the SHS and the spectroscopy sensor are in optical alignment, such that light exiting from the SHS directly passes to the spectroscopy sensor without optics configured to direct the light to the spectroscopy sensor.