Microfluidic apparatus, method of detecting substance in microfluidic apparatus, and spectrometer

1. A microfluidic apparatus, comprising:

a first substrate;

a microfluidic layer on the first substrate and defining a microfluidic channel, wherein the first substrate having a first side closer to the microfluidic layer, and a second side away from the microfluidic layer, the first side and the second side opposite each other;

a plurality of detectors on a side of the microfluidic channel away from the first substrate;

a unitary grating plate on the second side of the first substrate and comprising a plurality of grating blocks; and

a light extraction layer comprising a plurality of light extractors on the first side of the first substrate and configured to extract light diffracted by the plurality of grating blocks out of the first substrate;

wherein a respective one of the plurality of light extractors is optically coupled to grating blocks of a same wavelength selectivity of the plurality of grating blocks, and configured to extract light of a same color diffracted by the grating blocks of the same wavelength selectivity into extracted light of a same color;

grating blocks of different wavelength selectivity of the plurality of grating blocks are configured to respectively diffract light of different colors into different light extractors of the plurality of light extractors;

a respective one of the plurality of detectors is configured to detect the extracted light of a same color transmitted through the microfluidic channel; and

different detectors of the plurality of detectors are configured to respectively detect extracted light of different colors respectively from different light extractors of the plurality of light extractors;

wherein the plurality of detectors comprise a first detector, a second detector, and a third detector;

the grating blocks of different wavelength selectivity comprise a plurality of first grating blocks of a first wavelength selectivity, a plurality of second grating blocks of a second wavelength selectivity, and a plurality of third grating blocks of a third wavelength selectivity; and

the plurality of light extractors comprise a first light extractor, a second light extractor, and a third light extractor;

wherein the first light extractor is optically coupled to the plurality of first grating blocks of the first wavelength selectivity, and configured to extract light of a first color diffracted by the plurality of first grating blocks of the first wavelength selectivity into extracted light of the first color;

the second light extractor is optically coupled to the plurality of second grating blocks of the second wavelength selectivity, and configured to extract light of a second color diffracted by the plurality of second grating blocks of the second wavelength selectivity into extracted light of the second color;

the third light extractor is optically coupled to the plurality of third grating blocks of the third wavelength selectivity, and configured to extract light of a third color diffracted by the plurality of third grating blocks of the third wavelength selectivity into extracted light of the third color;

the first detector is configured to detect at least portion of the extracted light of the first color transmitted through the microfluidic channel;

the second detector is configured to detect at least portion of the extracted light of the second color transmitted through the microfluidic channel; and

the third detector is configured to detect at least portion of the extracted light of the third color transmitted through the microfluidic channel.

2. The microfluidic apparatus of claim 1 , wherein the respective one of the plurality of light extractors is configured to collimate light of a same color diffracted by the grating blocks of the same wavelength selectivity into substantially collimated light of a same color;

the respective one of the plurality of detectors is configured to detect the substantially collimated light of a same color transmitted through the microfluidic channel; and

different detectors of the plurality of detectors are configured to respectively detect substantially collimated light of different colors respectively from different light extractors of the plurality of light extractors.

3. The microfluidic apparatus of claim 1 , wherein the respective one of the plurality of light extractors is configured to converge light of a same color diffracted by the grating blocks of the same wavelength selectivity into focused light converging on a converging point;

the respective one of the plurality of detectors is configured to detect the focused light of a same color transmitted through the microfluidic channel, the converging point being on the respective one of the plurality of detectors; and

different detectors of the plurality of detectors are configured to respectively detect focused light of different colors respectively from different light extractors of the plurality of light extractors.

4. The microfluidic apparatus of claim 1 , further comprising a light source on the first side of the first substrate;

wherein the unitary grating plate is configured to diffract light emitted from the light source transmitted through the first substrate; and

the light source comprises a light emitting element and a light converging element configured to converge light emitted from the light emitting element into a converged light having a divergence angle between an outmost light beam of the converged light and a normal direction to the first side, the divergence angle being equal to or less than 30°.

5. The microfluidic apparatus of claim 4 , wherein the light converging element comprises a converging reflective mirror having a reflective surface on a side of the light emitting element away from the unitary grating plate, and configured to reflect light from the light emitting element to form the converged light.

6. The microfluidic apparatus of claim 4 , wherein the light converging element comprises a converging lens.

7. The microfluidic apparatus of claim 1 , wherein a respective one of the plurality of grating blocks is a volume Bragg grating.

8. The microfluidic apparatus of claim 1 , wherein at least two grating blocks of a same wavelength selectivity of the plurality of grating blocks are directly adjacent to each other, and form a grating group of the same wavelength selectivity for diffracting light of a same color.

9. The microfluidic apparatus of claim 1 , wherein the plurality of grating blocks are directly adjacent to each other.

10. A method of detecting a substance in a microfluidic apparatus, comprising:

providing a light source on a first side of a first substrate;

providing a unitary grating plate on a second side of the first substrate, wherein the unitary grating plate comprises a plurality of grating blocks, and the unitary grating plate is configured to diffract light emitted from the light source transmitted through the first substrate, the first side and the second side are opposite to each other;

providing a light extraction layer comprising a plurality of light extractors on the first side of the first substrate;

respectively diffracting light of different colors into different light extractors of the plurality of light extractors using grating blocks of different wavelength selectivity of the plurality of grating blocks;

extracting light of a same color diffracted by grating blocks of a same wavelength selectivity of the plurality of grating blocks into extracted light of a same color using a respective one of the plurality of light extractors;

providing a microfluidic layer on the first substrate and defining a microfluidic channel on a side of the first side away from the second side;

providing a plurality of detectors on a side of the microfluidic channel away from the first substrate;

detecting the extracted light of a same color transmitted through the microfluidic channel using a respective one of the plurality of detectors;

respectively detecting extracted light of different colors respectively from different light extractors of the plurality of light extractors using different detectors of the plurality of detectors;

wherein the plurality of detectors comprise a first detector, a second detector, and a third detector;

the grating blocks of different wavelength selectivity comprise a plurality of first grating blocks of a first wavelength selectivity, a plurality of second grating blocks of a second wavelength selectivity, and a plurality of third grating blocks of a third wavelength selectivity; and

the plurality of light extractors comprise a first light extractor, a second light extractor, and a third light extractor;

the method further comprises:

extracting light of a first color diffracted by the plurality of first grating blocks of the first wavelength selectivity into extracted light of the first color using the first light extractor;

extracting light of a second color diffracted by the plurality of second grating blocks of the second wavelength selectivity into extracted light of the second color using the second light extractor;

extracting light of a third color diffracted by the plurality of third grating blocks of the third wavelength selectivity into extracted light of the third color using the third light extractor;

detecting at least portion of the extracted light of the first color transmitted through the microfluidic channel using the first detector;

detecting at least portion of the extracted light of the second color transmitted through the microfluidic channel using the second detector; and

detecting at least portion of the extracted light of the third color transmitted through the microfluidic channel using the third detector.

11. The method of claim 10 , wherein the light source comprises a light emitting element and a light converging element; the method further comprises converging light emitted from the light emitting element into a converged light having a divergence angle between an outmost light beam of the converged light and a normal direction to the first side, the divergence angle being equal to or less than 30°.