Ultrafast laser micromachining is a promising candidate for micro- and nano-fabrication technology. Due to the high
precision of femtosecond ablation, laser-machined features can be added to devices prototyped by lithography. To
accomplish that, parametric studies of laser interrogation of materials of interest are necessary. We present femtosecond
laser ablation studies of glass, PDMS, fused silica, and diamond films. Samples were ablated by a 800 nm laser beam
with pulse width of 200 fs laser and repetition rates of up to 250 kHz. Our results include single- and multi-pulse laser
machining for fluidic and photonic devices. Feature size and structural dependences on ablation rates are discussed.
A freely diffusing single fluorescent molecule may be scrutinized for an extended duration within a confocal microscope
by actively trapping it within the femtoliter probe region. We present results from computational models and ongoing
experiments that research the use of multi-focal pulse-interleaved excitation with time-gated single photon counting and
maximum-likelihood estimation of the position for active control of the electrophoretic and/or electro-osmotic motion
that re-centers the molecule and compensates for diffusion. The molecule is held within a region with approximately
constant irradiance until it photobleaches and/or is replaced by the next molecule. The same photons used for
determining the position within the trap are also available for performing spectroscopic measurements, for applications
such as the study of conformational changes of single proteins. Generalization of the trap to multi-wavelength excitation
and to spectrally-resolved emission is being developed. Also, the effectiveness of the maximum-likelihood position
estimates and semi-empirical algorithms for trap control is discussed.