Drive laser for EUV light source
View Patent ↗A laser light source is disclosed having a laser oscillator producing an output beam; a first amplifier amplifying the output beam to produce a first amplified beam, and a second amplifier amplifying the first amplified beam to produce a second amplified beam. For the source, the first amplifier may have a gain medium characterized by a saturation energy (E s, 1 ) and a small signal gain (g o, 1 ); and the second amplifier may have a gain medium characterized by a saturation energy (E s, 2 ) and a small signal gain (g o, 2 ), with (g o, 1 )>(g o, 2 ) and (E s, 2 )>(E s, 1 ). In another aspect, a laser oscillator of a laser light source may be a cavity dumped laser oscillator, e.g. a mode-locked laser oscillator, q-switched laser oscillator and may further comprising a temporal pulse stretcher.
1. A laser light source comprising;
a laser oscillator producing an output beam;
a first amplifier amplifying said output beam to produce a first amplified beam, said first amplifier having a gain medium characterized by a saturation energy (E s, 1 ) and a small signal gain (g o, 1 ); and
a second amplifier amplifying said first amplified beam to produce a second amplified beam, said second amplifier having a gain medium characterized by a saturation energy (E s, 2 ) and a small signal gain (g o, 2 ), with (g o, 1 )>(g o, 2 ) and (E s, 2 )>(E s, 1 ); wherein said first amplifier gain medium comprises a gas having a first gas composition and said second amplifier gain medium comprises a gas having a gas composition different from said first gas composition.
2. A laser light source as recited in claim 1 wherein said gas comprises CO 2 .
3. A laser light source as recited in claim 1 further comprises a third amplifier amplifying said second amplified beam to produce a third amplified beam, said third amplifier having a gain medium characterized by a saturation energy (E s, 3 ) and a small signal gain (g o, 3 ), with (g o, 1 )>(g o, 2 )>(g o,3 ) and (E s, 3 )>(E s, 2 )>(E s, 1 ).
4. A laser light source as recited in claim 1 wherein said laser oscillator is a cavity dumped laser oscillator.
5. A laser light source as recited in claim 1 wherein said laser oscillator is a mode-locked laser oscillator.
6. A laser light source as recited in claim 1 wherein said laser oscillator is a q-switched laser oscillator.
7. A laser light source as recited in claim 4 further comprising a temporal pulse stretcher.
8. A laser light source as recited in claim 7 wherein said temporal pulse stretcher is positioned to receive laser pulses from said oscillator and produce stretched pulses therefrom for amplification by said first amplifier.
9. A laser light source as recited in claim 1 wherein said first amplifier gain medium is a gas at a gas pressure P 1 , and said second amplifier gain medium is a gas at a gas pressure P 2 , with P 1 ≠P 2 .
10. A laser light source comprising;
a laser oscillator producing an output beam;
a first amplifier amplifying said output beam to produce a first amplified beam, said first amplifier having a gain medium characterized by a saturation energy (E s, 1 ) and a small signal gain (g o, 1 ); and
a second amplifier amplifying said first amplified beam to produce a second amplified beam, said second amplifier having a gain medium characterized by a saturation energy (E s, 2 ) and a small signal gain (g o, 2 ), with (g o, 1 )>(g o, 2 ) and (E s, 2 )>(E s, 1 ) wherein said first amplifier gain medium is a gas at a gas pressure P 1 , and said second amplifier gain medium is a gas at a gas pressure P 2 , with P 1 ≠P 2 .
11. A laser light source as recited in claim 10 wherein said first amplifier gain medium comprises a gas having a first gas composition.
12. A laser light source as recited in claim 11 wherein said second amplifier gain medium comprises a gas having a gas composition different from said first gas composition.
13. A laser light source as recited in claim 11 wherein said gas comprises CO 2 .
14. A laser light source as recited in claim 10 further comprises a third amplifier amplifying said second amplified beam to produce a third amplified beam, said third amplifier having a gain medium characterized by a saturation energy (E s, 3 ) and a small signal gain (g o, 3 ), with (g o, 1 )>(g o, 2 )>(g o, 3 ) and (E s, 3 )>(E s, 2 )>(E s, 1 ).
15. A laser light source as recited in claim 10 wherein said laser oscillator is a cavity dumped laser oscillator.
16. A laser light source as recited in claim 10 wherein said laser oscillator is a mode-locked laser oscillator.
17. A laser light source as recited in claim 10 wherein said laser oscillator is a q-switched laser oscillator.
18. A laser light source as recited in claim 15 further comprising a temporal pulse stretcher.
19. A laser light source as recited in claim 18 wherein said temporal pulse stretcher is positioned to receive laser pulses from said oscillator and produce stretched pulses therefrom for amplification by said first amplifier.