Master oscillator-power amplifier drive laser with pre-pulse for EUV light source
View Patent ↗A device is described herein which may comprise an optical amplifier having a gain band including wavelengths λ 1 and λ 2 , with λ 1 ≠λ 2 ; a pre-pulse seed laser having a tuning module for tuning a pre-pulse output to wavelength λ 1 ; a main pulse seed laser generating a laser output having wavelength, λ 2 ; and a beam combiner for directing the pre-pulse output and the main pulse output on a common path through the optical amplifier.
1. A device comprising:
an optical amplifier having a gain band including wavelengths λ 1 and λ 2 , with λ 1 ≠λ 2 ;
a pre-pulse seed laser having a tuning module for tuning a pre-pulse output to wavelength λ 1 ;
a main pulse seed laser generating a laser output having wavelength, λ 2 , wherein at least one of said pre-pulse seed laser and said main pulse seed laser has a gain medium comprising CO 2 ; and
a beam combiner for directing the pre-pulse output and the main pulse output on a common path through the optical amplifier.
2. A device as recited in claim 1 wherein the tuning module comprises a grating.
3. A device as recited in claim 1 wherein said pre-pulse seed laser and said main pulse seed laser have gain media comprising CO 2 , and λ 1 and λ 2 correspond to rotational lines in a common vibrational branch.
4. A device as recited in claim 1 wherein said pre-pulse seed laser and said main pulse seed laser have gain media comprising CO 2 , and λ 1 and λ 2 correspond to rotational lines in different vibrational branches.
5. A device as recited in claim 1 wherein said pre-pulse seed laser and said main pulse seed laser have gain media comprising CO 2 , and λ 1 and λ 2 correspond to rotational lines in different vibrational branches and wherein said vibrational branches do not share a common upper level.
6. A device as recited in claim 1 wherein said pre-pulse seed laser comprises a sub-atmospheric, sealed, radio-frequency discharge, CO 2 laser.
7. A device for irradiating a target material to produce Extreme Ultraviolet (EUV) light, the device comprising:
an optical amplifier having a gain band including wavelengths λ 1 and λ 2 , with λ 1 ≠λ 2 ;
a pre-pulse seed laser generating a pre-pulse output having wavelength, λ 1 , and pulse energy, E PP ;
a main pulse seed laser generating a main pulse output having wavelength, λ 2 , and pulse energy, E MP , with E MP <1000×E PP ; and
a beam combiner for directing the pre-pulse output and the main pulse output onto a common beam path through the optical amplifier.
8. A device recited in claim 7 wherein the pre-pulse laser comprises a tuning module.
9. A device recited in claim 8 wherein the tuning module comprises a grating.
10. A device as recited in claim 7 wherein said pre-pulse seed laser and said main pulse seed laser have gain media comprising CO 2 , and λ 1 and λ 2 correspond to rotational lines in a common vibrational branch.
11. A device as recited in claim 7 wherein said optical amplifier has a gain media comprising CO 2 and produces a pre-pulse amplifier output pulse energy, E PP-AMPED and a main pulse amplifier output pulse energy, E MP-AMPED with E MP-AMPED >10×E PP-AMPED .
12. A device as recited in claim 7 wherein E MP <10×E PP .
13. A device as recited in claim 7 wherein said pre-pulse seed laser comprises a sub-atmospheric, sealed, radio-frequency discharge, CO 2 laser.
14. A device as recited in claim 7 wherein said pre-pulse seed laser and said main pulse seed laser have gain media comprising CO 2 , and λ 1 and λ 2 correspond to rotational lines in different vibrational branches.
15. A device as recited in claim 7 wherein said pre-pulse seed laser and said main pulse seed laser have gain media comprising CO 2 , and λ 1 and λ 2 correspond to rotational lines in different vibrational branches and wherein said vibrational branches do not share a common upper level.
16. A device comprising:
an optical amplifier having a gain media comprising CO 2 ,
a pre-pulse seed laser generating a pre-pulse output having wavelength λ 1 ,
a main pulse seed laser generating a main pulse output having wavelength, λ 2 , with λ 1 ≠λ 2 , and λ 1 and λ 2 correspond to rotational lines in a same CO 2 gain media vibrational branch; and
a beam combiner for directing the pre-pulse output and the main pulse output on a common path through the optical amplifier.
17. A device recited in claim 16 wherein the seed laser comprises a tuning module for tuning the pre-pulse output to wavelength λ 1 .
18. A device recited in claim 17 wherein the tuning module comprises a grating.
19. A device as recited in claim 16 wherein said pre-pulse seed laser comprises a sub-atmospheric, sealed, radio-frequency discharge, CO 2 laser.
20. A device as recited in claim 16 wherein said beam combiner comprises a dichroic beam combiner and said λ 1 and said λ 2 are separated by at least three rotational lines in said vibrational branch.