Ultrathin harmonic generators
- Lawrence Livermore National Lab., CA (United States). Nonlinear Optical Materials Group
In second-harmonic generation in optical materials with extremely large nonlinearity (about 1,000 that in KDP), efficient conversion may be expected for gain lengths of just a few micrometers. If the gain length is less than the coherence length, the phase-matching condition normally invoked for KDP and other common nonlinear materials may not apply. Devices based on such ultrathin media are potentially insensitive to wavelength, bandwidth, temperature, and poor beam quality. The authors have analyzed harmonic generation in ultrathin media to evaluate their materials requirements. They show that in such devices the conversion efficiency to the second harmonic is necessarily limited to about 25%, because higher harmonics are also necessarily generated with significant efficiencies. Ultrathin devices are therefore subject to large thermal loads, and perhaps optical damage arising from the generation of strong ultraviolet or soft X-ray harmonics. Whereas ultrathin media are not as efficient as conventional phase-matched crystals for second-harmonic generation, they do generate phase-coherent, multiple higher harmonics. As a consequence, they can generate optical square waves electromagnetic shock waves, and may find application as coherent soft X-ray generators.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6908484
- Journal Information:
- IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States), Vol. 27:9; ISSN 0018-9197
- Country of Publication:
- United States
- Language:
- English
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