used to characterize the material based upon the optical signal changes when used as an optical laser a propagating optical signal is again coupled into the microbubble to create circulating wgms an active lasing material is disposed within the microbubble and functions to efficiently amplify the circulating wgms fig4 illustrates an exemplary optical sensor 20 utilizing microbubble 10 of fig2 as a resonating device as shown a sample material liquid or gas is introduced into microcapillary 12 and flows therethrough in this particular embodiment input coupling of a u201c probing u201d optical signal is provided by an optical fiber taper 16 that is positioned with respect to microbubble 10 such a waist section 18 of optical fiber taper 16 contacts the outer surface of microbubble 10 in alternative embodiments an optical prism grating waveguide or other suitable coupling device may be used to introduce the probing optical signal to microbubble 10 referring back to fig4 the evanescent portion of the propagating optical signal will penetrate through the curved film forming the outer surface of microbubble 10 and begin to circulate as wgms along the interior of microbubble 10 the circulating wgms will interact with the sample material introduced to microcapillary 12 advantageously the geometry of microbubble 10 will confine the circulating wgms to the central region of microbubble 10 forcing these modes to continue to circulate and create the desired high q factor cavity that will continuously interact with the sample material and create a high sensitivity optical.