Quasi-phase-matched parametric chirped pulse amplification systems

Abstract

Use of quasi-phase-matched (QPM) materials for parametric chirped pulse amplification (PCPA) substantially reduces the required pump peak power and pump brightness, allowing exploitation of spatially-multimode and long duration pump pulses. It also removes restrictions on pump wavelength and amplification bandwidth. This allows substantial simplification in pump laser design for a high-energy PCPA system and, consequently, the construction of compact diode-pumped sources of high-energy ultrashort optical pulses. Also, this allows elimination of gain-narrowing and phase-distortion limitations on minimum pulse duration, which typically arise in a chirped pulse amplification system. One example of a compact source of high-energy ultrashort pulses is a multimode-core fiber based PCPA system. Limitations on pulse energy due to the limited core size for single-mode fibers are circumvented by using large multimode core. Limitations on pulse duration and beam quality due to multimode core are circumvented by using a PCPA scheme. Additionally, the large core of the multimode fiber facilitates cladding-pumping by inexpensive and high-power multiple-mode laser diodes.

What is claimed is: 
     
       1. An optical pulse amplification and delivery system, comprising:
 a pump source generating optical pump pulses of a predetermined duration; 
 a signal source generating optical signal pulses; 
 combining elements receiving and combining the optical pump pulses and the optical signal pulses, and providing combined optical pulses which are substantially temporally overlapped; a parametric amplifier comprising a quasi-phase-matched crystal receiving the combined optical pulses and amplifying the optical signal pulses using energy of the optical pump pulses; 
 a compressor which compresses the amplified optical signal pulses to a time duration substantially shorter than the predetermined duration of said optical pump pulses; and 
 an application unit receiving an output of said compressor and applying said output to a specified location. 
 
     
     
       2. A system as claimed in  claim 1 , wherein said application unit comprises a machine tool. 
     
     
       3. A system as claimed in  claim 1 , wherein said application unit comprises a surgical instrument. 
     
     
       4. A system as claimed in  claim 1 , wherein said combined optical pulses as delivered to said application unit, are femtosecond regime duration pulses. 
     
     
       5. A system as claimed in  claim 1 , wherein said pump source comprises one of a diode laser system and a diode laser system combined in cascade with a Yb fiber amplifier system. 
     
     
       6. The optical pulse amplification system of  claim 1 , wherein said signal source comprises:
 a signal pulse generator; and 
 a stretcher receiving and stretching signal pulses generated by the signal pulse generator, to a duration approximating said predetermined duration. 
 
     
     
       7. The optical pulse amplification system of  claim 1 , wherein said predetermined duration is greater than about 100 picoseconds. 
     
     
       8. The optical pulse amplification system of  claim 1 , wherein said pump source is a multimode source. 
     
     
       9. The optical pulse amplification system of  claim 1 , wherein said pump source comprises at least one multimode fiber amplifier. 
     
     
       10. An optical pulse amplification and delivery system, comprising:
 a pump source generating optical pump pulses;   a signal source generating optical signal pulses;   combining elements receiving and combining the optical pump pulses and the optical signal pulses, and providing combined optical pulses which are substantially temporally overlapped;   an amplifier including a non-linear crystal receiving the combined optical pulses and amplifying the optical signal pulses using energy of the optical pump pulses;   a compressor for compressing the amplified optical signal pulses to a time duration substantially shorter than the predetermined duration of said optical pump pulses; and   an application unit receiving an output of said compressor and applying said output to a specified location.   
     
     
       11. An optical pulse amplification and delivery system, comprising:
 a pump source generating optical pump pulses of a predetermined duration;   a signal source generating optical signal pulses;   combining elements receiving and combining the optical pump pulses and the optical signal pulses, and providing combined optical pulses which are substantially temporally overlapped;   an amplifier including a non-linear crystal receiving the combined optical pulses and amplifying the optical signal pulses using energy of the optical pump pulses; and   a compressor for compressing the amplified optical signal pulses to a time duration substantially shorter than the predetermined duration of said optical pump pulses.   
     
     
       12. The optical pulse amplification system of claim 10, wherein said signal source comprises:
 a signal pulse generator; and   a stretcher receiving and stretching signal pulses generated by the signal pulse generator.   
     
     
       13. The optical pulse amplification system of claim 11, wherein said signal source comprises:
 a signal pulse generator; and   a stretcher receiving and stretching signal pulses generated by the signal pulse generator, to a duration approximating said predetermined duration.   
     
     
       14. The optical pulse amplification system of claim 11, wherein said compressor comprises a diffraction grating pair.