Andrew J. Merriam

Efficient gas-phase generation of coherent vacuum ultraviolet radiation.

We report the demonstration of a pulsed atomic lead (Pb) vapor-based vacuum ultraviolet frequency converter from 233 to 186 nm with unity photon-conversion efficiency. This conversion is attained without phase matching.

Nonlinear optics at maximum coherence

We describe nonlinear optical processes which utilize maximum coherence of a non–allowed transition. The nonlinear susceptibility for such processes is of the same order of magnitude as is the linear susceptibility. This allows frequency converters and optical parametric oscillators with bandwidths which are on order of their centre frequency.

Efficient self-seeding of a pulsed Ti3+:Al2O3 laser.

We describe the design considerations and operating characteristics of a compact, widely tunable, narrow-linewidth, megawatt-class pulsed laser system based on Ti(3+):Al(2)O(3) (Ti:sapphire) pumped by the second harmonic of a 1.06-microm Nd:YAG laser. The system delivers 10 mJ in a 5-ns near-transform-limited single-longitudinal-mode (SLM) pulse with a threshold of 20 mJ and a slope efficiency greater than 40%. By the technique of self-seeding, in which a portion of the gain mediums spontaneous fluorescence is coupled back to the laser cavity, SLM operation may be obtained across the entire gain profile of Ti:sapphire with a minimum number of optical components and without external seeding.

Efficient self-seeding of a pulsed Ti:sapphire laser

We report the tunable single longitudinal mode (SLM) operation of a pulsed Ti:sapphire laser based on a simple, dual cavity, Littman-type stable resonator geometry, which routinely generates SLM output pulses with several-nanosecond durations and energies up to 10 mJ.

Efficient vapor-phase vacuum ultraviolet (VUV) frequency conversion

Summary form only given. The techniques of electromagnetically induced transparency (EIT) may be employed in order to create an effective nonlinear response at a given wavelength which is equal in magnitude to the linear response at that wavelength. Physically, this allows frequency converters wherein 100% photon-to-photon conversion occurs in a single coherence length, i.e., in that distance which causes a /spl pi/ phase slip between the driving polarization and the generated electromagnetic wave. These ideas were first implemented by Jain et al. (1996), to convert 425 nm to 293 nm, in a medium consisting of a single isotope of Pb. This paper reports the demonstration of a vapor-phase VUV frequency converter from 233 nm to 186 nm with an energy conversion efficiency exceeding 35%; the maximum generated signal energy and power were 250 /spl mu/J and 25 kW. The net conversion efficiency to 186 nm, including all beams, is roughly 2%. These wavelengths were chosen to demonstrate the utility of this type of frequency converter to generate wavelengths outside the transparency window of most crystalline media. Our technique involves the application of two strong laser fields which are almost two-photon resonant with a Raman transition of the Pb atoms.

Efficient gas-phase VUV frequency up-conversion

We describe a pulsed, atomic lead (Pb) vapor-based vacuum ultraviolet (VUV) frequency converter from 233 to 186 nm with near-unity photon conversion efficiency. This conversion is attained without phasematching and is accomplished by using electromagnetically induced transparency to drive a Raman transition to near-maximal coherence without loss or beam blow-up. Under these conditions, the linear and nonlinear polarizations of the generated 186-nm field are of the same order and complete conversion from the 233-nm field occurs within a single (nonphasematched) coherence length.