Graduate Exam Abstract

David Alessi

M.S. Final

December 8, 2006, 2:30 pm

Engineering B2

Demonstration Of High Repetition Rate Soft X-Ray Lasers At Wavelengths Near 30 Nm In Ne-Like Ions

Abstract: This thesis describes the development and characterization of soft x-ray lasers operating at 5 Hz in at wavelengths near 30 nm in transitions of neon-like ions. The results were obtained using laser-created plasmas formed by irradiation of solid targets with pulses from a high power Ti:Sapphire laser. The use of a pumping configuration consisting of a normal incidence plasma forming pre-pulse and a delayed grazing incidence short pulse allows for efficient pumping. Lasing was observed on the 2p53p1S0’2p53s1P1 transition of Ne-like titanium (» = 32.6 nm) Ne-like vanadium (» = 30.4 nm), and Ne-like chromium (» = 28.6 nm). Lasing was also observed in the 2p53d1P1’2p53p1P1 transition of Ne-like titanium (» = 30.1 nm) which relies on optical trapping of the 2.335 nm resonant transition linking the laser upper level to the ground state (2s22p6). Of these laser transitions, the 32.6 nm and 30.4 nm lasers in Ne-like Ti and V operated in the gain saturated regime. All of the lasers were measured to produce maximum intensity when the pump laser operated at a grazing incidence angle of 20º. The 32.6 nm Ne-like Ti laser intensity is optimal with a 6 ps FWHM pump pulse duration. The 32.6 nm Ne-like Ti was measured to produce an average power in excess of 2 µW operating at 5 Hz repetition rate. The peak spectral brightness of this laser is on the order of 1x1024 photons s-1 mm-2 mrad-2 within 0.01% spectral bandwidth and exceeds by several orders of magnitude that of a third generation synchrotron beam line operating at this wavelength.

Adviser: Dr. Jorge Rocca
Non-ECE Member: Dr. Chiao-Yao She (physics)
Member 3: Dr. Carmen Menoni
Addional Members:


Program of Study: