Triple sum frequency coherent multidimensional imaging

1. A method of obtaining a multidimensional image of a sample, the method comprising:

(a) directing a first coherent light pulse having a first frequency ω 1 and a first wave vector k 1 at a first location in a sample,

(b) directing a second coherent light pulse having a second frequency ω 2 and a second wave vector k 2 at the first location,

(c) directing a third coherent light pulse having a third frequency ω 3 and a third wave vector k 3 at the first location and

(d) detecting a coherent output signal having a fourth frequency ω 4 and a fourth wave vector k 4 from the first location,

wherein ω 4 =±ω 1 ±ω 2 ±ω 3 and k 4 =±k 2 ±k 3 ,

wherein at least two of the coherent light pulses each are configured to excite a different transition to a discrete quantum state of a molecule or molecular functionality in the sample,

and further wherein steps (a)-(d) are repeated at a sufficient number of other locations in the sample to provide the multidimensional image.

2. The method of claim 1 , wherein ω 4 =ω 1 +ω 2 +ω 3 and k 4 =k 1 +k 2 +k 3 .

3. The method of claim 2 , wherein the three coherent light pulses are each configured to excite a different transition to a discrete quantum state in the molecule or molecular functionality.

4. The method of claim 2 , wherein one of the coherent light pulses is configured to excite a transition to a vibrational quantum state, one of the coherent light pulses is configured to excite a transition to a different vibrational quantum state and one of the coherent light pulses is configured to excite a transition to a virtual electronic state, whereby a Raman transition is induced returning the molecule or molecular functionality to a lower energy state.

5. The method of claim 2 , wherein one of the coherent light pulses is configured to excite a transition to a vibrational quantum state, one of the coherent light pulses is configured to excite a transition to an electronic quantum state and one of the coherent light pulses is configured to excite a transition to a virtual electronic state, whereby a Raman transition is induced returning the molecule or molecular functionality to a lower energy state.

6. The method of claim 3 , wherein one of the coherent light pulses is configured to excite a transition to a vibrational quantum state, one of the coherent light pulses is configured to excite a transition to a different vibrational quantum state and one of the coherent light pulses is configured to excite a transition to an electronic quantum state, whereby a resonance Raman transition is induced returning the molecule or molecular functionality to a lower energy state.

7. The method of claim 3 , wherein one of the coherent light pulses is configured to excite a transition to a vibrational quantum state, one of the coherent light pulses is configured to excite a transition to an electronic quantum state and one of the coherent light pulses is configured to excite a transition to a different electronic quantum state, whereby a resonance Raman transition is induced returning the molecule or molecular functionality to a lower energy state.

8. The method of claim 2 , wherein the frequencies of the at least two coherent light pulses are resonant with their respective transitions.

9. The method of claim 3 , wherein the frequencies of the three coherent light pulses are resonant with their respective transitions.

10. The method of claim 2 , wherein the three coherent light pulses interact with the sample to generate the coherent output signal over a path length and the path length is in the range of from about 1 μm to about 200 μm.

11. The method of claim 2 , wherein the multidimensional image is a three-dimensional image.

12. The method of claim 2 , wherein at least two of the coherent light pulses are independently tunable.

13. The method of claim 2 , wherein the three coherent light pulses are independently tunable.

14. The method of claim 2 , wherein the three coherent light pulses are configured in a non-collinear beam geometry.

15. A scanning microscope for obtaining a multidimensional image of a sample, the scanning microscope comprising:

(a) optics configured to receive coherent light pulses and to direct the coherent light pulses to a first location in the sample, the coherent light pulses comprising:

(i) a first coherent light pulse having a first frequency ω 1 and a first wave vector k 1 ,

(ii) a second coherent light pulse having a second frequency ω 2 and a second wave vector k 2 , and

(iii) a third coherent light pulse having a third frequency ω 3 and a third wave vector k 3 ,

wherein at least two of the coherent light pulses each are configured to excite a different transition to a discrete quantum state of a molecule or molecular functionality in the sample;

(b) a stage configured to support the sample; and

(c) a detector positioned to detect a coherent output signal generated from the first location, the coherent output signal having a fourth frequency ω 4 and a fourth wave vector k 4 , wherein ω 4 =±ω 1 ±ω 2 ±ω 3 and k 4 =±k 1 ±k 2 ±k 3 ,

and further wherein the scanning microscope is configured to illuminate a sufficient number of other locations in the sample with the three coherent light pulses to provide the multidimensional image.

16. The scanning microscope of claim 15 , wherein ω 4 =ω 1 +ω 2 +ω 3 and k 4 =k 1 +k 2 +k 3 .

17. The scanning microscope of claim 16 , wherein the optics are configured to direct the three coherent light pulses in a non-collinear beam geometry.

18. The scanning microscope of claim 16 , further comprising one or more light sources configured to generate the three coherent light pulses.

19. The scanning microscope of claim 18 , wherein at least two of the coherent light pulses are independently tunable.

20. The scanning microscope of claim 18 , wherein the three coherent light pulses are independently tunable.