Methods and systems for coherent multidimensional spectroscopy

1. A method for coherent multidimensional spectroscopy, the method comprising:

(a) illuminating a location in a sample with a set of m coherent light pulses, each coherent light pulse having an initial frequency ω m and an initial wave vector {right arrow over (k)} m , wherein m≥2, to generate a coherent output signal having an initial frequency ω output =Σ±ω m and an initial wave vector {right arrow over (k)} output =Σ±{right arrow over (k)} m ;

(b) scanning a first coherent light pulse of the set of m coherent light pulses across a set of i frequency values, wherein i≥2, the set of i frequency values including the first coherent light pulse having initial frequency ω 1 ;

(c) scanning, simultaneously, a second coherent light pulse of the set of m coherent light pulses across a set of i correlated frequency values, the set of i correlated frequency values including the second coherent light pulse having initial frequency ω 2 , wherein each correlated frequency value is associated with a corresponding frequency value of the set of i frequency values as a correlated frequency grouping;

wherein each correlated frequency value is selected so that the coherent output signal generated at each correlated frequency grouping equals the initial frequency ω output and the coherent output signal generated at each correlated frequency grouping equals the initial wave vector {right arrow over (k)} output ; and

(d) detecting the coherent output signal.

2. The method of claim 1 , wherein m=2 and the initial frequency is ω output =ω 1 +ω 2 and the initial wave vector is {right arrow over (k)} output ={right arrow over (k)} 1 +{right arrow over (k)} 2 .

3. The method of claim 1 , wherein m=3 and the initial frequency is ω output =±ω 1 ±ω 2 ±ω 3 and the initial wave vector is {right arrow over (k)} output =±{right arrow over (k)} 1 ±{right arrow over (k)} 2 ±{right arrow over (k)} 3 .

4. The method of claim 1 , wherein m=4 and the initial frequency is ω output =±ω 1 ±ω 2 ±ω 3 ±ω 4 and the initial wave vector is {right arrow over (k)} output =±{right arrow over (k)} 1 ±{right arrow over (k)} 2 ±{right arrow over (k)} 3 ±{right arrow over (k)} 4 .

5. The method of claim 3 , wherein the initial frequency is ω output =ω 1 −ω 2 +ω 3 and the initial wave vector is {right arrow over (k)} output ={right arrow over (k)} 1 −{right arrow over (k)} 2 +{right arrow over (k)} 3 .

6. The method of claim 3 , wherein the initial frequency is ω output =ω 1 +ω 2 +ω 3 and the initial wave vector is {right arrow over (k)} output ={right arrow over (k)} 1 +{right arrow over (k)} 2 +{right arrow over (k)} 3 .

7. The method of claim 1 , wherein angles are defined between propagation axes of each pair of coherent light pulses in the set of m coherent light pulses and the angles are fixed during steps (a)-(c).

8. The method of claim 1 , wherein step (b) is characterized by a frequency change between frequency values in the set of i frequency values and step (c) is characterized by a correlated frequency change between correlated frequency values in the set of i correlated frequency values, and further wherein the frequency change and the correlated frequency change differ in one or more of magnitude and direction.

9. The method of claim 1 , wherein the first and second coherent light pulses are collinear.

10. The method of claim 1 , further comprising

(e) scanning, simultaneously, a third coherent light pulse of the set of m coherent light pulses across a second set of i correlated frequency values, the second set of i correlated frequency values including the third coherent light pulse having initial frequency ω 3 , wherein each correlated frequency value in the second set of i correlated frequency values is also a member of the correlated frequency grouping;

wherein each correlated frequency value in the second set of i correlated frequency values is selected so that the coherent output signal generated at each correlated frequency grouping equals the initial frequency ω output and the coherent output signal generated at each correlated frequency grouping equals the initial wave vector {right arrow over (k)} output .

11. The method of claim 10 , wherein the first, the second, and the third coherent light pulses are collinear.

12. A system for coherent multidimensional spectroscopy, the system comprising:

an optical subsystem configured to illuminate a location in a sample with a set of m coherent light pulses, each coherent light pulse having an initial frequency ω m and an initial wave vector {right arrow over (k)} m , wherein m≥2, to generate a coherent output signal having an initial frequency ω output =Σ±ω m and an initial wave vector {right arrow over (k)} output =Σ±{right arrow over (k)} m ;

a detection subsystem configured to detect the coherent output signal; and

a controller comprising a processor and a non-transitory computer-readable medium operably coupled to the processor, the non-transitory computer-readable medium comprising instructions, that, when executed by the processor, cause the system to

(a) illuminate the location with the set of m coherent light pulses to generate the coherent output signal;

(b) scan a first coherent light pulse of the set of m coherent light pulses across a set of i frequency values, wherein i≥2, the set of i frequency values including the first coherent light pulse having initial frequency ω 1 ;

(c) scan, simultaneously, a second coherent light pulse of the set of m coherent light pulses across a set of i correlated frequency values, the set of i correlated frequency values including the second coherent light pulse having initial frequency ω 2 , wherein each correlated frequency value is associated with a corresponding frequency value of the set of i frequency values as a correlated frequency grouping;

wherein each correlated frequency value is selected so that the coherent output signal generated at each correlated frequency grouping equals the initial frequency ω output and the coherent output signal generated at each correlated frequency grouping equals the initial wave vector {right arrow over (k)} output ; and

(d) detect the coherent output signal.

13. The system of claim 12 , the computer-readable medium further having computer-readable instructions stored thereon that, when executed by the processor, cause the controller to generate the set of i correlated frequency values and output the set of i correlated frequency values to the system.

14. A method for coherent multidimensional spectroscopy using the system of claim 12 , the method comprising:

(a) illuminating the location with the set of m coherent light pulses to generate the coherent output signal;

(b) scanning the first coherent light pulse of the set of m coherent light pulses across the set of i frequency values;

(c) scanning, simultaneously, the second coherent light pulse of the set of m coherent light pulses across the set of i correlated frequency values; and

(d) detecting the coherent output signal.

15. A controller for controlling the operations of a system for coherent multidimensional spectroscopy, the controller comprising:

a processor; and

a non-transitory computer-readable medium operably coupled to the processor, the non-transitory computer-readable medium comprising instructions, that, when executed by the processor, cause the system to:

(a) illuminate a location in a sample with a set of m coherent light pulses, each coherent light pulse having an initial frequency ω m and an initial wave vector {right arrow over (k)} m , wherein m≥2, to generate a coherent output signal having an initial frequency ω output =Σ±ω m and an initial wave vector {right arrow over (k)} output =Σ±{right arrow over (k)} m ;

(b) scan a first coherent light pulse of the set of m coherent light pulses across a set of i frequency values, wherein i≥2, the set of i frequency values including the first coherent light pulse having initial frequency ω 1 ;

(c) scan, simultaneously, a second coherent light pulse of the set of m coherent light pulses across a set of i correlated frequency values, the set of i correlated frequency values including the second coherent light pulse having initial frequency ω 2 , wherein each correlated frequency value is associated with a corresponding frequency value of the set of i frequency values as a correlated frequency grouping;

wherein each correlated frequency value is selected so that the coherent output signal generated at each correlated frequency grouping equals the initial frequency ω output and the coherent output signal generated at each correlated frequency grouping equals the initial wave vector {right arrow over (k)} output ; and

(d) detect the coherent output signal.

16. The controller of claim 15 , the computer-readable medium further having computer-readable instructions stored thereon that, when executed by the processor, cause the controller to generate the set of i correlated frequency values and output the set of i correlated frequency values to the system.

17. A non-transitory computer-readable medium comprising computer-readable instructions stored thereon that, when executed by a processor, cause a controller for controlling the operations of a system for coherent multidimensional spectroscopy to direct the system to:

(a) illuminate a location in a sample with a set of m coherent light pulses, each coherent light pulse having an initial frequency ω m and an initial wave vector {right arrow over (k)} m , wherein m≥2, to generate a coherent output signal having an initial frequency ω output =Σ±ω m and an initial wave vector wave vector {right arrow over (k)} output =Σ±{right arrow over (k)} m ;

(b) scan a first coherent light pulse of the set of m coherent light pulses across a set of i frequency values, wherein i≥2, the set of i frequency values including the first coherent light pulse having initial frequency ω 1 ;

(c) scan, simultaneously, a second coherent light pulse of the set of m coherent light pulses across a set of i correlated frequency values, the set of i correlated frequency values including the second coherent light pulse having initial frequency ω 2 , wherein each correlated frequency value is associated with a corresponding frequency value of the set of i frequency values as a correlated frequency grouping;

wherein each correlated frequency value is selected so that the coherent output signal generated at each correlated frequency grouping equals the initial frequency ω output and the coherent output signal generated at each correlated frequency grouping equals the initial wave vector {right arrow over (k)} output ; and

(d) detect the coherent output signal.

18. The non-transitory computer-readable medium of claim 17 , further comprising instructions that, when executed by the processor, cause the controller to generate the set of i correlated frequency values and output the set of i correlated frequency values to the system.