Dale Capewell

Serial time-encoded amplified microscopy (STEAM) is an entirely new imaging modality that enables ultrafast continuous real-time imaging with high sensitivity. By means of optical image amplification, STEAM overcomes the fundamental tradeoff between sensitivity and speed that affects virtually all optical imaging systems. Unlike the conventional microscope systems, the performance of STEAM depends not only on the lenses, but also on the properties of other components that are unique to STEAM, namely the spatial disperser, the group velocity dispersion element, and the back-end electronic digitizer. In this paper, we present an analysis that shows how these considerations affect the spatial resolution, and how they create a trade-off between the number of pixels and the frame rate of the STEAM imager. We also quantify how STEAM's optical image amplification feature improves the imaging sensitivity. These analyses not only provide valuable insight into the operation of STEAM technology but also serve as a blue print for implementation and optimization of this new imaging technology.

We demonstrate an endoscope-compatible single-fiber-based device that performs simultaneous confocal microscopy and high-precision laser microsurgery. The method is based on mapping of two-dimensional sample coordinates onto the optical spectrum and allows us to perform two-dimensional imaging and microsurgery without any mechanical movement of the probe or the sample. The technology holds promise for creating highly miniaturized endoscopes for applications such as brain tumor, pediatric, and endovascular surgeries where high-precision, small, and flexible probes are required.

The Direct Simulation Monte Carlo (DSMC) method for simulating rarified gasdynamics has been applied to the problem of pulses laser deposition. Both 1D and 2D axisymmetric simulations were carried out. In both, a source of silicon expands into the background gas of argon in the presence of a diffusely reflecting substrate. Density, temperature, and axial flow velocity for each species are computed as functions of position and time. Particle flux and energy incident on the substrate are also monitored as functions of time. The simulation results are in good agreement with experimental plume diagnostics and film growth rates vs. pressure data.