Ultrahigh intensity laser for laser wakefield acceleration

The next generation of high peak power CPA laser systems will be improved in compactness, simplicity, and cost. Yb:glass is a suitable choice for the amplifier medium in such a laser system necessary for an all-optical GeV accelerator. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87564/2/68_1.pd

The development of high-peak-power and average-power ytterbium-doped chirped-pulse amplifiers.

This thesis will investigate ytterbium-doped laser materials and new techniques to produce simpler and more compact chirped-pulse amplification (CPA) laser systems. Yb:glass is a promising directly diode-pumped material as a result of several attractive properties. The 2-ms upper-state lifetime, broad fluorescence spectrum, 15-wt% doping concentration, greater than 40-J/cm 2 saturation fluence, and 7% quantum defect of Yb:glass distinguish it as a material which can amplify short pulses, can be pumped easily by free-running lasers or laser diodes, and can store an extremely high energy density for CPA. The two difficulties of Yb:glass are its relatively low emission cross-section and poor thermal conductivity. The former problem is addressed by using a low-gain low-loss regenerative amplifier to efficiently extract the stored energy. Spectroscopic measurements and simulations of the quasi-3-level CPA process are performed to optimize the extraction efficiency and amplified bandwidth. Based on these simulations, a Yb:glass regnerative amplifier was constructed producing 150 mJ, the highest energy obtained from a short-pulse regenerative amplifier. This regenerative amplifier pumped by a free-running high-energy pump source in combination with a diode-pumped Yb:glass oscillator demonstrate a compact terawatt laser system with excellent beam quality defined by the regenerative cavity. One solution for the thermal problem is introduced and demonstrated through the use of a moving gain medium. The laser medium is pumped with a uniform transverse spatial profile and is lased during the resulting transient uniform temperature profile. This simple technique for the removal of thermal problems is well-suited for long pulse energy extraction from Yb:glass, in which the high saturation fluence can be fully taken advantage. A technique for the precise control of the gain spectrum by spatially dispersing an injected pulse in a regenerative amplifier is discussed. This technique results in numerous advantages, including increasing the mode size using the bandwidth of the laser. Broadening the spectrum by greater than a factor of five in a spatially-dispersed Yb:YAG laser demonstrates the feasibility for a truly directly-diode-pumped high-average-power 100-fs source.Ph.D.Applied SciencesElectrical engineeringOpticsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131606/2/9929787.pd

Congenital chylous ascites presenting with bilateral inguinal hernia and umbilical hernia: A case report: Congenital chylous ascites

Chylous ascites refers to the leakage of lipid rich milky fluid into the peritoneal cavity. This usually occurs following trauma or obstruction of the lymphatic system. Moreover, an existing clear ascitic fluid can turn chylous as a secondary event. Milky appearance on gross appearance along with high fat (triglyceride) content usually suggestive of the diagnosis. We are reporting a 3 months infant with chylous ascites diagnosed during bilateral inguinal herniotomy. The patient presented bilateral scrotal with umbilical swelling for last one month. Examination showed bilateral inguinal hernia, umbilical hernia with mild abdominal distension. Bilateral herniotomy and subsequent ultrasound guided paracentesis revealed milky peritoneal fluid. Biochemical analysis revealed plenty of lymphocytes,   high  triglyceride  content  with  increased cellularity and no abnormal cells suggestive of chylous ascites. Lymphoscintigraphy revealed leak from retroperitoneal   lymphatics.   Child   improved   following dietary modification and octreotide therapy without any surgical intervention. The aim of this case report is to describe the unusual presentation, it’s clinical and biochemical factors and role of conservative treatment of a patient with congenital chylous ascites

Ultrafast ytterbium-doped bulk lasers and laser amplifiers

We review recent achievements with ultrafast bulk lasers and amplifiers based on Yb:YAG and Yb:glass. Special attention is paid to those aspects of the quasi-three-level nature of these gain media that are important for short-pulse generation. The potential of Yb-doped media for efficient short-pulse generation and amplification is compared to their Nd-doped counterparts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42156/1/340-69-1-3_90690003.pd

Investigation of human anthrax outbreak in Koraput district of Odisha, India

Background: Anthrax is a zoonotic infection resulting from the bacteria Bacillus anthracis. Humans contract cutaneous anthrax by coming into contact, and gastrointestinal (GI) anthrax by consumption of infected animals or animal products. An outbreak investigation was conducted to confirm the occurrence of the anthrax outbreak, comprehend its extent, understand the epidemiological characteristics, identify the outbreak's cause, and propose control measures. Methods: A descriptive epidemiology was carried out for this outbreak investigation. We defined a suspected human cutaneous anthrax case as appearance of skin lesions and symptoms (itching/redness/swelling) and a suspected case of GI anthrax as appearance of diarrhoea/abdominal pain/vomiting in a resident of Koraput district after being associated with slaughtering and/or consumption of carcass during 5th April to 15th May 2023. The etiological hypothesis was formulated using descriptive epidemiological methods. Laboratory confirmation was performed by real-time polymerase chain reaction (RT-PCR). Statistical analyses were conducted using SPSS 25. Results: A total of 47 clinically suspected anthrax cases were identified during the outbreak in five villages of Koraput district in Odisha. The epidemic curve indicated multiple point-source exposures starting from 13th April 2023. About 10 cases were identified by RT-PCR testing as confirmed cases of anthrax. No death was recorded in this outbreak investigation. Conclusions: Based on a thorough examination of epidemiological survey results and laboratory findings, we conclude that the outbreak was of human cutaneous and GI anthrax. Exposures from handling dead animals were associated with cutaneous anthrax, whereas eating uncooked meat of dead sheep was associated with gastrointestinal anthrax