Frequency conversion arrangement for optimising properties of a harmonic of a laser

1. A frequency conversion arrangement ( 100 ) for optimizing properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability,

wherein the arrangement comprises:

a first non-linear crystal (X 1 ), which is designed in such a way as to convert a first wavelength (λ 1 ) partially into a second wavelength (λ 2 ); and

an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes of the beam profiles of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) differently; and

a second non-linear crystal (X 2 ), which is designed in such a way as to generate a third wavelength (λ 3 ) from the unconverted part of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ),

the second non-linear crystal (X 2 ) having an entry face (A 1 ) and an exit face (A 2 ), and the exit face (A 2 ) running obliquely to the entry face (A 1 ),

characterized in that

the optical unit comprises at least one prism (P), which is rotatable about at least one axis so as to influence the respective main axes (x 1 , y 1 , x 2 , y 2 ) of the beam profiles differently.

2. The frequency conversion arrangement ( 100 ) according to claim 1 ,

characterized in that

the second wavelength (λ 2 ) is the second harmonic of the first wavelength (λ 1 ).

3. The frequency conversion arrangement ( 100 ) according to claim 1 ,

characterized in that

the third wavelength (λ 3 ) is a wavelength corresponding to the second harmonic of the first wavelength (λ 1 ) or the second harmonic of the second wavelength (λ 2 ) or the sum or difference frequency of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ).

4. The frequency conversion arrangement ( 100 ) according to claim 1 ,

characterized in that

the exit face (A 2 ) of the second non-linear crystal (X 2 ) is substantially disposed in a Brewster arrangement.

5. The frequency conversion arrangement ( 100 ) according to claim 4 , characterized in that the exit face (A 2 ) of the second non-linear crystal (X 2 ) is substantially disposed in a Brewster arrangement with respect to the third wavelength (λ 3 ).

6. The frequency conversion arrangement ( 100 ) according to claim 1 ,

characterized in that

the exit face (A 2 ) of the second non-linear crystal is uncoated.

7. The frequency conversion arrangement ( 100 ) according to claim 1 ,

characterized in that

the exit face (A 2 ) of the second non-linear crystal is coated.

8. The frequency conversion arrangement ( 100 ) according to claim 7 ,

characterized in that

the exit face (A 2 ) of the second non-linear crystal is coated with an antireflection coating for the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) and/or the third wavelength (λ 3 ) and/or a p coating.

9. The frequency conversion arrangement ( 100 ) according to claim 1 ,

characterized in that

the exit face (A 2 ) of the second non-linear crystal is nanostructured.

10. A system ( 200 ) for frequency conversion of a laser, comprising:

a frequency conversion arrangement ( 100 ) according to claim 1 ;

a laser system (L) generating a beam (B) having the first wavelength ( 21 ); and

a beam profile size adaptation unit (T), which is designed such as to adapt the size of the beam profile of the beam (B);

wherein the beam profile, after the adaptation of the size by the beam profile size adaptation unit (T), is supplied to the frequency conversion arrangement ( 100 ).

11. The system ( 200 ) according to claim 10 ,

characterized in that

the size of the beam profile of the beam (B) before the frequency conversion arrangement, has a diameter of at least 250 μm.

12. The system ( 200 ) according to claim 11 ,

characterized in that

the size of the beam profile of the beam (B) before the frequency conversion arrangement, has a diameter of at least 500 μm.

13. The system ( 200 ) according to claim 11 ,

characterized in that

the size of the beam profile of the beam (B) before the frequency conversion arrangement, has a diameter of at least 1,000 μm.

14. The system ( 200 ) according to claim 10 ,

characterized in that

the laser system (L) is a pulsed laser system preferably having pulse durations in the microsecond range, further preferred in the nanosecond range, still further preferred in the picosecond range.

15. The system ( 200 ) according to claim 14 ,

characterized in that

the laser system (L) is a pulsed laser system having pulse durations in the microsecond range.

16. The system ( 200 ) according to claim 14 ,

characterized in that

the laser system (L) is a pulsed laser system having pulse durations in the nanosecond range.

17. The system ( 200 ) according to claim 14 ,

characterized in that

the laser system (L) is a pulsed laser system having pulse durations in the picosecond range.

18. The system ( 200 ) according to claim 10 ,

characterized in that

the laser system (L) is a continuous beam laser system.

19. A frequency conversion arrangement ( 100 ) for optimizing properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability,

wherein the arrangement comprises:

a first non-linear crystal (X 1 ), which is designed in such a way as to convert a first wavelength (λ 1 ) partially into a second wavelength (λ 2 ); and

an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes of the beam profiles of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) differently; and

a second non-linear crystal (X 2 ), which is designed in such a way as to generate a third wavelength (λ 3 ) from the unconverted part of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ),

the second non-linear crystal (X 2 ) having an entry face (A 1 ) and an exit face (A 2 ), and the exit face (A 2 ) running obliquely to the entry face (A 1 ),

characterized in that

a/the prism (P) of the optical unit is transversely translatable so as to adjust and/or compensate for a runtime difference (Δt) between the first wavelength (λ 1 ) and the second wavelength (λ 2 ) continuously.

20. A frequency conversion arrangement ( 100 ) for optimizing properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability,

wherein the arrangement comprises:

a first non-linear crystal (X 1 ), which is designed in such a way as to convert a first wavelength (λ 1 ) partially into a second wavelength (λ 2 ); and

an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes of the beam profiles of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) differently; and

a second non-linear crystal (X 2 ), which is designed in such a way as to generate a third wavelength (λ 3 ) from the unconverted part of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ),

the second non-linear crystal (X 2 ) having an entry face (A 1 ) and an exit face (A 2 ), and the exit face (A 2 ) running obliquely to the entry face (A 1 ),

characterized in that

the optical unit is coordinated, in particular by an apex angle and a material of the prism (P), to the obliquely running exit face (A 2 ) of the second non-linear crystal (X 2 ), such as to generate a rotationally symmetrical beam profile for the third wavelength (λ 3 ), in particular independent of the symmetry of the beam profile of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ).

21. A system ( 200 ) for frequency conversion of a laser, comprising:

a frequency conversion arrangement ( 100 ) for optimizing properties of a harmonic of the laser, in particular a beam profile and/or a long-term stability,

wherein the arrangement comprises:

a first non-linear crystal (X 1 ), which is designed in such a way as to convert a first wavelength (λ 1 ) partially into a second wavelength (λ 2 ); and

an optical unit, which in particular comprises at least one prism (P), which is designed in such a way as to influence the main axes of the beam profiles of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) differently; and

a second non-linear crystal (X 2 ), which is designed in such a way as to generate a third wavelength (λ 3 ) from the unconverted part of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ),

the second non-linear crystal (X 2 ) having an entry face (A 1 ) and an exit face (A 2 ), and the exit face (A 2 ) running obliquely to the entry face (A 1 );

a laser system (L) generating a beam (B) having the first wavelength (λ 1 ); and

a beam profile size adaptation unit (T), which is designed such as to adapt the size of the beam profile of the beam (B);

wherein the beam profile, after the adaptation of the size by the beam profile size adaptation unit (T), is supplied to the frequency conversion arrangement ( 100 ),

characterized by

a beam profile analysis unit (K) for measuring the dimensions of the respective main axes (x 1 , y 1 , x 2 , y 2 , x 3 , y 3 ) of the respective beam profile of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) and/or the third wavelength (λ 3 ), wherein the beam profile analysis unit (K) in particular comprises at least one camera and/or an M 2 analysis unit.

22. A frequency conversion method, for optimizing properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability, wherein the method comprises the following steps:

a first conversion step, in which a first wavelength (λ 1 ) is partially converted into a second wavelength (λ 2 ) in a first non-linear crystal (X 1 ),

a beam profile adaptation step, in which the beam profiles of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) are influenced in their respective main axes (x 1 , y 1 , x 2 , y 2 ) differently,

a second conversion step, in which a third wavelength (λ 3 ) is generated from the non-converted part of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) in a second non-linear crystal (X 2 ),

wherein the second non-linear crystal (X 2 ) has an entry face (A 1 ) and an exit face (A 2 ), and the exit face (A 2 ) running obliquely to the entry face (A 1 ),

wherein the beam profile adaptation step is performed by rotating at least one prism (P) about at least one axis.

23. The frequency conversion method according to claim 22 , comprising a step for adjusting an intensity of a portion of the first wavelength (λ 1 ) involved in the first and/or the second conversion step.

24. A frequency conversion method for optimizing properties of a harmonic of a laser, in particular a beam profile and/or a long-term stability, wherein the method comprises the following steps:

a first conversion step, in which a first wavelength (λ 1 ) is partially converted into a second wavelength (λ 2 ) in a first non-linear crystal (X 1 ),

a beam profile adaptation step, in which the beam profiles of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) are influenced in their respective main axes (x 1 , y 1 , x 2 , y 2 ) differently,

a second conversion step, in which a third wavelength (λ 3 ) is generated from the non-converted part of the first wavelength (λ 1 ) and/or the second wavelength (λ 2 ) in a second non-linear crystal (X 2 ),

wherein the second non-linear crystal (X 2 ) has an entry face (A 1 ) and an exit face (A 2 ), and the exit face (A 2 ) running obliquely to the entry face (A 1 ),

wherein an aspect ratio of the beam of the third wavelength (λ 3 ) is continuously adjustable by the beam profile adaptation step.