Jonathan M Evans

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OBJECTIVE To evaluate the technique of native collagen fluorescence imaging for assessing the extent of welded areas for tissues exposed to different near-infrared (NIR) laser wavelengths. BACKGROUND Native fluorescence imaging may be used to identify the distribution of collagen and elastin in tissues. Our past work demonstrated that different welding(More)
It is demonstrated that the incorporation of an acousto-optic modulator within the cavity of a self-mode-locked Ti:sapphire laser can lead to self-starting and stable generation of pulses that have durations of 60 fs when the acousto-optic device is driven regeneratively from the laser output. Data are also presented that show that the application of(More)
The predictions of two models of sound propagation in concentrated emulsions are compared with experimental measurements of ultrasonic velocity and attenuation in emulsions with volume fractions up to 0.7. The core-shell model includes irreversible heat transfer, viscoinertial forces, and multiple scattering [McClements et al., J. Acoust. Soc. Am. 105,(More)
Continuous-wave and mode-locked Cr(4+):Ca(2)GeO(4) lasers that use a fiber laser pump source were demonstrated. The continuous-wave Cr(4+):Ca(2)GeO(4) laser yielded a maximum output power of 415 mW at 1420 nm and a tuning range of 1335-1492 nm. With a saturable-absorber mirror, 60-ps pulses and 110-mW maximum output power were generated from a passively(More)
Nine dioxygenated D-homoandrostanes were incubated with Rhizopus nigricans to investigate the effect of D-ring modification on microbiological hydroxylation. Structure determination of the products by NMR spectroscopy, and in certain cases independent synthesis of their oxidised products, showed that in contrast to 5 alpha-androstanes the majority of the(More)
Continuous-wave tunable laser operation of direct diode-pumped Cr(4+):Mg(2)SiO(4) (Cr:forsterite) and Cr(4+):Ca(2)GeO(4) (cunyite) crystal were demonstrated. Diode-pumped Cr:forsterite was tunable over the 1236-1300-nm spectral range. The maximum output of 10 mW was measured at 1260 nm for 640 mW of pump power absorbed by the crystal. Diode-pumped laser(More)
A method is described by which a wavefront-reconstruction technique is utilized to record the effects of a turbulent medium on the propagation of optical beams. By this technique both amplitude and phase information in a two-dimensional cross section of a received optical beam are recorded. The mode structure of the source is not seen to be critical in this(More)