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 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 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 Theoretical Analysis of the Hydrogen Chloride and Hydrogen Fluoride Chemical Laser Systems written by Paul A. Kittle and published by . This book was released on 1967 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report gives the results of gain calculations, developed by J.C. Polanyi, when applied to the hydrogen fluoride and hydrogen chloride chemical lasing systems. The details of converting existing experimental and theoretical information into data usable in the gain calculations are discussed. The computer programs are supplied in the appendix. (Author).
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 A Theoretical and Experimental Investigation of the Mechanisms of the Hydrogen fluoride Pulsed Chemical Laser written by Joseph J. T. Hough and published by . This book was released on 1975 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Supersonic Cw HF Chemical Laser Zero Power Gain written by Thuong Xuan Nguyen and published by . This book was released on 1990 with total page 464 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 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book AIAA 24th Plasmadynamics Lasers Conference 93 3151 93 3195 written by and published by . This book was released on 1993 with total page 488 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 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 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 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 A Theoretical Assessment of Vibrational to Rotational Energy Exchange in the Hydrogen Fluoride Chemical Laser written by Robert Clinton Brown and published by . This book was released on 1980 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 36th AIAA Plasmadynamics and Lasers Conference 05 5037 05 5390 written by and published by . This book was released on 2005 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 01 2862 01 2952 written by and published by . This book was released on 2001 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrogen Fluoride Chemical Laser a Demonstration of Pure Chemical Pumping written by Paul A. Kittle and published by . This book was released on 1968 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report describes two types of apparatus - a single pulse system and a flow system - used to demonstrate the phenomenon of chemical pumping. The results of experiments leading to the successful demonstration of chemical pumping are described. The comparisons between theoretical and experimental results are discussed. (Author).
