{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/20805"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/20805","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Experimental and theoretical study of CW hydrogen fluoride chemical laser residual fundamental gain","abstract":"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.","abstract_html":"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.","abstract_has_math":true,"creators":["Theodoropoulos, Panagiotis Theodoros"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Sentman, Lee H."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:49:48Z","date_published":"2011-05-07T12:49:48Z","updated_at":"2026-07-22T22:25:16Z","subjects":["Engineering, Aerospace"],"languages":["eng"],"rights":["Copyright 1992 Theodoropoulos, Panagiotis Theodoros"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9236606","(UMI)AAI9236606"],"render_values":[{"text":"AAI9236606","href":null,"code":true},{"text":"(UMI)AAI9236606","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/20805","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Sentman, Lee H."]},{"key":"dc:creator","label":"Author","values":["Theodoropoulos, Panagiotis Theodoros"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:49:48Z","10000-01-01","1992"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Aerospace"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1992 Theodoropoulos, Panagiotis Theodoros"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9236606","(UMI)AAI9236606","http://hdl.handle.net/2142/20805"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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 ($\\Delta\\alpha$) 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.","Made available in DSpace on 2011-05-07T12:49:48Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9236606.pdf: 14512934 bytes, checksum: aeb71679a76b64d4cfd6364e80e18091 (MD5) Previous issue date: 1992","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:46:23Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:20:47-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Experimental and theoretical study of CW hydrogen fluoride chemical laser residual fundamental gain"]}]}],"canonical_facts":{"dc:contributor":["Sentman, Lee H."],"dc:creator":["Theodoropoulos, Panagiotis Theodoros"],"dc:date":["2011-05-07T12:49:48Z","10000-01-01","1992"],"dc:description":["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 ($\\Delta\\alpha$) 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.","Made available in DSpace on 2011-05-07T12:49:48Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9236606.pdf: 14512934 bytes, checksum: aeb71679a76b64d4cfd6364e80e18091 (MD5) Previous issue date: 1992","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:46:23Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:20:47-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9236606","(UMI)AAI9236606","http://hdl.handle.net/2142/20805"],"dc:language":["eng"],"dc:rights":["Copyright 1992 Theodoropoulos, Panagiotis Theodoros"],"dc:subject":["Engineering, Aerospace"],"dc:title":["Experimental and theoretical study of CW hydrogen fluoride chemical laser residual fundamental gain"],"dc:type":["text"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:16Z"}