Automated bandwidth / wavelength adjustment systems and methods for short pulse lasers and optical amplifiers
View Patent ↗Embodiments are directed to systems and methods for adjusting a wavelength, bandwidth or both. Such systems and methods may be applicable to laser beams within a laser cavity or amplifier. For some embodiments, such systems and methods may be used to allow a user to set a desired wavelength and bandwidth of a short pulse laser system for operation at those parameters without further adjustment by the user.
1. A tunable laser system, comprising:
a laser cavity defined by an end mirror disposed at a first end of the laser cavity and an output coupler disposed at a second end of the laser cavity;
a gain medium disposed within the laser cavity including an opposed pair of beam input surfaces;
a wavelength tuning system configured to tune the laser system to laser at a band centered at a predetermined wavelength set by a user;
a bandwidth control system configured to maintain the bandwidth of the lasing energy of the system at the predetermined bandwidth set by the user; and
a controller operatively coupled to the wavelength tuning system and the bandwidth control system and configured to adjust the wavelength tuning system and the bandwidth control system to maintain the respective predetermined center operating wavelength and bandwidth.
2. The laser system of claim 1 wherein the laser cavity comprises a ring cavity including a plurality of mirrors.
3. The laser system of claim 1 further comprising a user interface device configured to allow the user to select the predetermined center operating wavelength and the bandwidth.
4. The laser system of claim 1 further comprising a pump source configured to generate pump energy that passes through the gain medium along the laser beam path within the gain medium.
5. The device of claim 1 wherein the gain medium comprises a Ti:Sapphire crystal.
6. The laser system of claim 1 further comprising a beam location sensor coupled to the controller and a mirror positioning actuator mechanically coupled to a mirror of the laser system and in operative communication the controller wherein the controller is configured to receive beam position data from the beam location sensor and instruct the mirror positioning actuator to adjust the mirror to maintain a desired beam path.
7. The laser system of claim 1 wherein the controller comprises a computer processor.
8. The laser system of claim 3 wherein the user interface device comprises a GUI user interface device.
9. The laser system of claim 1 wherein the wavelength tuning system comprises a prism pair and an adjustable optical slit.
10. The laser system of claim 9 wherein the positions of a first opaque edge of the slit and second opaque edge of the slit are determined by a software program that sets both the position and the spread of the adjustable optical slit to achieve both a desired center operating wavelength and bandwidth.
11. The laser system of claim 1 wherein the bandwidth control system comprises a prism pair with at least one of the prisms coupled to an actuator which is in operative communication with the controller for adjusting the amount of refractive prism material disposed within a beam path.
12. The laser system of claim 1 wherein at least one of the beam input surfaces of the laser gain medium comprises an angled beam input surface which is formed at an angle which is non-perpendicular to a laser beam path within the gain medium.
13. The device of claim 4 wherein the pump source comprises a laser.
14. The device of claim 13 wherein the pump source comprises a diode pumped solid state laser.
15. The laser system of claim 1 wherein the wavelength tuning system comprises a refractive prism disposed in a laser beam path which is configure to transversely position the laser beam path according to wavelength and a narrow translatable slit that is translatable in a direction along the direction of transverse position.
16. The laser system of claim 10 wherein the actuator for translation of the refractive prism comprises a motor.
17. The laser system of claim 1 wherein the wavelength tuning system is tunable over a wavelength range of about 450 nm.
18. The laser system of claim 17 wherein the wavelength tuning system is tunable to a center wavelength of about 650 nm to about 1100 nm.
19. The laser system of claim 1 wherein a pulse width of an output of the laser system is less than about 1 ps [picosecond].
20. The laser system of claim 1 wherein a pulse width of an output of the laser system is about 10 fs to about 100 fs.
21. The laser system of claim 1 wherein the wavelength tuning system is configured to tune the laser output to a wavelength of about 780 nm to about 820 nm.
22. The laser system of claim 1 wherein the bandwidth control system is configured to generate a bandwidth range of about 10 nm to about 120 nm.
23. The laser system of claim 1 wherein the controller configures the bandwidth control system and wavelength tuning system components to achieve predetermined center operating wavelength and bandwidth selected by the user by correlating these selected parameters to previously calibrated configurations stored in a lookup data chart.
24. The laser system of claim 1 further comprising a dispersion control system.
25. The laser system of claim 24 wherein the dispersion control system comprises a dispersion control coating on at least one reflective optic of the laser system.
26. The laser system of claim 25 wherein the reflective mirror and output coupler both comprise the dispersion control coating on a reflective surface thereof.
27. The laser system of claim 26 wherein the dispersion control coating comprises materials selected from the group consisting of silicone oxide and titanium oxide.
28. The laser system of claim 24 wherein the dispersion control system comprises at least one chirped reflective mirror.
29. The laser system of claim 28 wherein the at least one chirped reflective mirror comprises a parabolic curve for chirped coatings.
30. The laser system of claim 29 wherein the parabolic curve of the chirped coating is tailored to a specific laser cavity of the laser system.
31. The laser system of claim 28 wherein the chirped reflective surface of the chirped reflective mirror comprises layers of at least two different materials having different indices of refraction.
32. The laser system of claim 31 wherein the layers of two different materials of the chirped reflective coating have thicknesses of about 1 nm to about 400 nm.
33. The laser system of claim 32 wherein the layers of two different materials of the chirped reflective coating have thicknesses of about 2 nm to about 200 nm.
34. A tunable laser system, comprising:
a laser cavity defined by an end mirror disposed at a first end of the laser cavity and an output coupler disposed at a second end of the laser cavity;
a gain medium disposed within the laser cavity including an opposed pair of beam input surfaces;
a wavelength tuning system configured to tune the laser system to lase at a band centered at the predetermined wavelength set by the user;
a bandwidth control system configured to maintain the bandwidth of the lasing energy of the system at the predetermined bandwidth set by the user; and
a dispersion control system comprising at least one chirped reflective mirror including a parabolic response curve configured to control dispersion within the laser cavity of the laser system.
35. The laser system of claim 34 wherein the laser cavity comprises a ring cavity including a plurality of mirrors.
36. The laser system of claim 34 wherein a chirped reflective surface of the at least one chirped reflective mirror comprises layers of at least two different materials having different indices of refraction.
37. The laser system of claim 36 wherein the layers of two different materials of the chirped reflective coating have thicknesses of about 1 nm to about 400 nm.
38. The laser system of claim 37 wherein the layers of two different materials of the chirped reflective coating have thicknesses of about 2 nm to about 200 nm.
39. The laser system of claim 35 further comprising a user interface device configured to allow a user to select a predetermined center operating wavelength and bandwidth.
40. The laser system of claim 39 further comprising a controller operatively coupled to the user interface device, wavelength tuning system and bandwidth control system actuators and configured to adjust the wavelength tuning system and bandwidth control system to maintain the respective predetermined center operating wavelength and bandwidth.
41. The laser system of claim 34 further comprising a pump source configured to generate pump energy that passes through the gain medium along the laser beam path within the gain medium.
42. A method of generating short-pulse laser output having a preselected center operating wavelength and preselected bandwidth, comprising:
entering a desired preselected center operating wavelength and bandwidth into a user interface of a laser system;
processing the preselected center operating wavelength and bandwidth data previously entered into the user interface with a processor and correlating the data with corresponding settings for a wavelength tuning system and a bandwidth control system of the laser system;
communicating the respective settings from the processor to the wavelength tuning system and bandwidth control system such that the wavelength tuning system and bandwidth control system assume respective configurations corresponding to the respective settings; and
pumping a gain medium disposed within a laser cavity of a laser system to generate a laser beam within the laser cavity having a center operating wavelength at the pre-selected center operating wavelength and a bandwidth at the pre-selected bandwidth.
43. The method of claim 42 further comprising sensing a position of the laser beam within the laser cavity with a position sensor, communicating the laser beam position to the controller, processing the beam position data with the processor, generating position correction data with the processor and communicating the position correction data from the processor to a beam position actuator operatively coupled to an optical path within the laser system cavity.
44. The method of claim 43 wherein communicating the position correction data from the processor to a beam position actuator operatively coupled to an optical path within the laser system cavity comprises communicating the position correction data from the processor to a piezoelectric actuator operatively coupled to a reflective mirror of the laser cavity and adjusting the orientation of the reflective mirror to redirect the laser beam to a desired beam path.
45. The method of claim 42 further comprising passing the laser beam through at least one coating on a reflective optic of the laser system, the at least one coating configured to control dispersion of the laser beam.