Download or read book Experimental and Theoretical Study of Cw HF Chemical Laser Overtone Performance written by David Leon Carroll and published by . This book was released on 1992 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overtone performance of the UIUC supersonic cw HF chemical laser was characterized as a function of flow rates, cavity pressure, mode volume, mirror reflectivity and method of He injection. The overtone performance was optimized by the same set of flow rates that optimized the fundamental performance. When the absorption/scattering losses of the mirrors were taken into account, an overtone efficiency of 70-90% was achieved, which is the highest reported to date. The overtone efficiency was a strong function of media saturation. There was no significant change in overtone power and efficiency as the mode volume increased. However, there were an increase in the number of lasing lines and a shift to higher J lines. Overtone performance was as sensitive to cavity pressure as fundamental performance. There was no significant change in overtone efficiency when the method of He injection was changed. Base region absorption by ground state HF has a significant effect on fundamental and overtone performance. Even with very high degrees of saturation, approximately 10% of the total power was lost when the He purge was turned off. For a laser having an extensive data base with well characterized mirrors to firmly establish the Rigrod parameters g$sb0$ and I$sb{rm sat}$, the accuracy to which the mirror reflectivities can be deduced using measured mirror transmissivities, measured outcoupled power and Rigrod theory is approximately $pm$0.07% for high reflectivity overtone mirrors. Rigrod theory shows that a higher media saturation yields a higher overall overtone efficiency, but does not necessarily yield a higher measureable power (power in the bucket). For low absorption/scattering loss overtone mirrors and a 5% penalty in outcoupled power, the intracavity flux and hence the mirror loading can be reduced by more than a factor of two when the gain length is long enough to well saturate the media. The inclusion of HF-H$sb2$ multi-quantum VV transfer reactions in the ORNECL model significantly improved the prediction of the zero power gains for the H$sb2$ rich UI supersonic laser. The inclusion of absorption by SF$sb{rm x}$ molecules in the model significantly improved the prediction of the Fabry-Perot spectra.
Download or read book Experimental and Theoretical Study of CW Hydrogen Fluoride Chemical Laser Residual Fundamental Gain written by Panagiotis Theodoros Theodoropoulos and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new technique that uses a multi-line probe beam to measure the gain on several lines simultaneously was developed. This new technique was used to measure the gains of the peak fundamental lines P$sb1$ (4-9) and P$sb2$(4-9) while lasing on the overtone, for three levels of media saturation. The suppression of the fundamental gains obtained at relatively high media saturation with 99.7/99.7% reflective mirrors was essentially the same as that obtained with 55% higher intracavity flux with 99.8/99.86% reflective mirrors. The gains of the low J lines P$sb1$(4-6) and P$sb2$(4-6) were suppressed 41% to 84%; the gains of the high J lines P$sb1$(7-9) and P$sb2$(7-9) were suppressed 3% to 43%. The 1 $to$ 0 lines were suppressed more than the 2 $to$ 1 lines. The maximum suppression occurred between 2 and 6 mm downstream from the nozzle exit plane, near the center of the 9 mm overtone beam. Simulation of the experiments with a rotational nonequilibrium computer model showed that the fundamental gains are determined by three independent mechanisms when lasing occurs on the overtone. First, overtone lasing decreases the gains of the P$sb1$(J) and P$sb2$(J) lines whose upper or lower levels are directly involved in P$sb{20}$(J) overtone lasing. Second, overtone lasing reduces the rate at which the low J v = 2 states are populated by rotational relaxation and increases the rate at which the low J v = 0 states are populated by rotational relaxation, resulting in suppression of the low J fundamental gains whose upper or lower levels are not directly involved in overtone lasing. Third, overtone lasing reduces the rate at which the HF(0,J) and HF(1,J) states are populated by the various collisional deactivation processes. With 10% of the original rotational relaxation rate, the computer model was in reasonable agreement with the measured zero power gain profiles. The model over predicted the fundamental gain suppression ($Deltaalpha$) for the P$sb1$(8,9) and P$sb2$(8,9) lines whose upper or lower levels were directly involved in overtone lasing, and under predicted the suppression for lines P$sb1$(4) and P$sb2$(4,5). The model predicted the suppression for lines P$sb1$(5-7) and P$sb2$(6,7) reasonably well. With the original rotational relaxation rate, the model was in reasonable agreement with the measured suppression of all P$sb1$(4-9) and P$sb2$(4-9) lines. However, with the original RR rate, the model's agreement with the experimental zero power gain profiles was not adequate.
Download or read book A Theoretical and Experimental Study of Cw HF Chemical Laser Performance written by Wolfram Otto Mosebach and published by . This book was released on 1982 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Theoretical Study of Cw HF Chemical Laser Residual Fundamental Gain written by Panagiotis Theodoros Theodoropoulos and published by . This book was released on 1992 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of CW HF Chemical Laser Overtone Performance written by John Willis Otto and published by . This book was released on 1993 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Resonators and Coherent Optics written by Anup Bhowmik and published by . This book was released on 1993 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Symposium on Gas Flow and Chemical Lasers written by and published by . This book was released on 1994 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Cw HF Chemical Laser Amplifier Performance and Zero Power Gain written by Panagiotis Theodoros Theodoropoulos and published by . This book was released on 1987 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pulsed Hydrogen Fluoride Overtone Chemical Laser Studies written by and published by . This book was released on 1993 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study of HF chemical lasers operating on overtone transitions, OTs, in a photolytically initiated, pulsed laser facility was conducted. The primary objective was to obtain comparisons of the specific energy performance of pulsed HF, chain reaction driven, chemical laser resonators when operating only on fundamental transitions, delta V = 1, and only on first overtone transitions, delta V = 2. The initial efforts were the buildup of the experimental test facility with which excellent performance as an FT HF laser was demonstrated. However, attempts to produce OT lasing using lamda- variable reflectivity mirror coatings (to promote and suppress, simultaneously, the OT and FT mechanisms) were only marginally successful, even though major facility modifications were made to reduce cavity losses, suppress FT superradiance (ASE), suppress parasitic modes and increase pulse duration. Finally, CW OT lasing was demonstrated using the OT optical components in a combustion-driven, blowdown test facility. A specific energy level, sigma = 266 w/gm/sec, was inferred from the measurements. HF Chemical lasers, HF Overtone lasers, Pulsed photolytically initiated chemical lasers.
Download or read book An Experimental Study of Fabry Perot and Stable Resonator CW HF Chemical Laser Performance written by Gus Tsioulos and published by . This book was released on 1985 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the International Conference on Lasers written by and published by . This book was released on 2001 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical Performance of an HF Chemical CW Laser written by George Emanuel and published by . This book was released on 1972 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantitative analysis of an HF cw chemical laser is presented that includes the influence of stimulated emission on the reacting medium. The numerically determined solutions encompass one-dimensional fluid mechanics, chemical kinetics, radiative de-excitation, and their mutual interaction. A comprehensive parametric study examines the effects due to changed plenum conditions, mixture ratios, and cavity parameters. Detailed discussions are presented of (1) vibration-vibration and vibration-translation energy exchange, (2) chemical efficiency, (3) mechanisms that cause lasing termination, and (4) cavity operation with a selective grating. (Author).
Download or read book High power Laser Ablation written by and published by . This book was released on 2004 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 30th Plasmadynamics and Lasers Conference written by and published by . This book was released on 1999 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Cw HF Chemical Laser Performance written by Anthony James Eyre and published by . This book was released on 1999 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 1996 with total page 1422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
