{"686423":{"#nid":"686423","#data":{"type":"event","title":"MS Defense by Federico Preve","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003EFederico Preve\u003C\/strong\u003E\u003Cbr\u003E\u003Cem\u003E(Advisor: Prof. Steinberg]\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003Ewill defend a doctoral master\u2019s thesis entitled,\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ELow Noise Double-Beam Laser Absorption Spectroscopy for Ammonia Sensing\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EOn\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWednesday, November 26 at 11:00 a.m.\u0026nbsp;\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003E\u0026nbsp;Ben T. Zinn Combustion Laboratory Room 107\u003C\/strong\u003E\u003Cbr\u003E\u003Cbr\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAbstract\u003C\/strong\u003E\u003Cbr\u003EThis thesis focuses on adapting an active noise-cancellation circuit for double-beam laser absorption spectroscopy to improve ammonia concentration measurements. By suppressing common-mode laser intensity noise, the circuit enhances absorption sensitivity without requiring complex modulation techniques. In this approach, a tunable diode laser beam is split into two paths: a signal beam that passes through an absorption cell and a reference beam that bypasses any absorbing medium. The two beams are independently detected, and their corresponding photocurrents are fed into an electronic circuit designed to suppress the common-mode noise on laser intensity, thereby enhancing the diagnostic technique\u2019s accuracy. This architecture remains cost-effective and has the potential to achieve shot-noise-limited performance.\u003C\/p\u003E\u003Cp\u003EA circuit originally designed by Philip Hobbs was adapted, simulated in Analog Devices LTspice, prototyped on a breadboard and ultimately implemented on a printed circuit board. Performance was evaluated using a water-vapor absorption setup and compared against both a standard DAS sensor and a commercial double-beam noise-cancellation module from MKS\u2013Newport. Results show a clear improvement in NEA over standard DAS, with performance approaching that of the commercial system. Finally, extended-range InGaAs photodetectors were integrated to enable ammonia detection, and the circuit was used to record room-temperature ammonia absorption line shapes and time-resolved absorption measurements of ammonia oxidation under post-reflected shock conditions in shock-tube experiments.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee\u003C\/strong\u003E\u003C\/p\u003E\u003Cul\u003E\u003Cli\u003EProf. Adam Steinberg \u2013 School of Aerospace Engineering (advisor)\u003C\/li\u003E\u003Cli\u003EProf. Wenting Sun\u2013 School of Aerospace Engineering\u003C\/li\u003E\u003Cli\u003EDr. Shawn Wehe \u2013 Principal Research Engineer, School of Aerospace Engineering\u003C\/li\u003E\u003C\/ul\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ELow Noise Double-Beam Laser Absorption Spectroscopy for Ammonia Sensing\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Low Noise Double-Beam Laser Absorption Spectroscopy for Ammonia Sensing"}],"uid":"27707","created_gmt":"2025-11-13 21:32:09","changed_gmt":"2025-11-13 21:33:05","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-11-26T11:00:00-05:00","event_time_end":"2025-11-26T13:00:00-05:00","event_time_end_last":"2025-11-26T13:00:00-05:00","gmt_time_start":"2025-11-26 16:00:00","gmt_time_end":"2025-11-26 18:00:00","gmt_time_end_last":"2025-11-26 18:00:00","rrule":null,"timezone":"America\/New_York"},"location":" Ben T. Zinn Combustion Laboratory Room 107","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"111531","name":"ms defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}