Research Of PDMS-based Microfluidic Lasers

Microfluidic light sources represent a novel way to integrate light sources into microfluidic system. In contract to traditional lasers, micro liquid dye lasers have the following advantages: size miniaturization, diversification in tunable means and integration in microchip. This paper studies two PDMS-based micro lasers.Whispering gallery mode optical microcavities have high quality factor and good optical field localization. We use convenient method to fabricate microcavities with tunable sizes. By brushing a layer of dye-doped polydimethylsiloxane(PDMS) on an optical fiber, the bottle-shaped microcavities can be self-formed due to the high surface tension. Different diameters can be fabricated by brushing different volume droplets with different speeds. Since PDMS has thermosetting, solid microcavities with high quality factor will be formed after heating. The threshold of whispering gallery mode laser in microcavities can be as low as several ?J/mm2. This paper discusses not only the relationship between lasing radiation and polarization property of pump laser, but also the relationship of lasing threshold with the size of microcavities. The convenient fabrication method and high quality factor make these microcavities very suitable for integration in microfluidic system.In this work, we introduce an on chip random laser based on PDMS wrinkle induced disordered structure, which further simplifies the random laser fabrication process by getting rid of lithography procedures. Stretched PDMS strips are disposed by plasma. After the relaxation of disposed PDMS, the wrinkles are formed at the surface of PDMS. Due to the disorder of the wrinkles, multiple scattering can be efficaciously amplified. As a result, lasing action with a relatively low threshold can be established when the optical gain is larger than the optical loss without a cavity resonator. The sensitivity of emission spectrum with respect to pump position perturbation also indicates the randomness of the wrinkle period. It also indicts the stable of our random laser that the laser emission spectrums at a randomly selected position with same pump energy are consistent. The chip-scale disorder-based light source delivers the possibility in microfluidic laser source integration as well as in related optofluidic laser applications.