Different last pulse lengths are often used to incite different effects from nanoparticles. Higher energy, shorter laser pulses, for example, are often used in laser-induced flourescence (LIF). Alternatively, nanosecond laser pulses can be used for laser-induced breakdown spectroscopy (LIBS) or laser-induced incandescence (LII). Depending on your intended purpose, you could use any number of these types. For example, LII can be used to detect the volume fraction of nanoparticles in an aerosol. What is your intended purpose?

Thank you Timothy for your response. I wish to know, what pulse duration would be appropriate for nanoparticle detection . if the intended pulsed laser is not used, what would be the additional effects or shaort comings while using the larger or shorter pulses than required pulse duraions.

I would agree with Héctor García. Also important is the material you are examining. Metal or carbonaceous nanoparticles can withstand much higher temperatures and thus have a different range of technique that can be used to detect them. Lower melting point materials of complex geometries will be subjected to distortion at those same laser fluences.

It would also depend on whether the nanoparticles are in an aerosol, where laser-induced incandescence (LII) with a nanosecond pulse could do what you want, or solution, where a technique like dynamics light scattering (DLS) is a good option.

Thank you Gracia and Timothy for your responses to my query. My study was to detect the metal nanoparticles dispersed in aqueous solution. So, if use a different pulse duration lasers, i want to know the changes in detection profiles. Assume the particles to be spherical in nature. For a nanometer sized sphere, would it be proper to use a micro or pico/femtosecond laser pulses.