Ultra-fast laser has been used in laser sensing and laser communication systems as well as for raison d'etre of
Target-to-Noise Ratio (TNR or SNR) remote control. Foundation of these quite different applications is in unique ability of ultrafast
laser to change photonic characteristics when ultra-short laser pulse interacts with photonic semiconductor. Ultrafast
laser is capable to sweep potential free carriers for period of time that is comparable with free carrier's life time and
thereto, ultra-short pulse is able to "bleach" photonic bandgap semiconductor making it temporally insensitive to its
genuine in-band irradiance. Energy transfer into semiconductor lattice follows the "bleaching". Energy transfer may
have different physical mechanisms-direct thermal as well as
non-thermal or electronic transfer, leading initially to
temporal lattice structure changes, and, with respect to pulse intensity, eventually to band gap collapse and even phase
changes in the semiconductor. However, for the purpose of fine sensing the only mild lattice disturbance is important.
That will limit focus of our consideration of laser-semiconductor interaction by relatively low intensity ultra-fast and
fast laser pulses. Ultra-fast and fast lasers open almost unlimited opportunities in band gap photonic applications by
allowing remotely engineer the characteristics of active and passive systems such as bandwidth, spectral responsivity,
detectivity, response time etc. In this paper we will discuss applications of ultra-fast lasers-lasers with femto-seconds
pulse width and, to some extend-fast lasers-with picoseconds pulse width, to remote engineering of photonic
characteristics of active and passive IR and electro-optical systems.