“…Glasses containing metal nanoparticles exhibit an ultrafast electron response within a few of picoseconds, and also have large third-order optical nonlinearities because of the large local-field enhancement factor and the strong resonant absorption of the surface plasmon [1][2][3][4][5][6][7][8]. Thus, these materials have been intensively studied since the middle eighties of the last century, owing to their applications in ultrafast all-optical switching, ultrafast imaging, optical telecommunication, signal processing, and so forth [7][8][9][10][11][12].…”