Song Jiangxin, Lin Jintian, Tang Jialei, Liao Yang, He Fei, Wang Zhaohui, Qiao Lingling, Sugioka Koji, Cheng Ya
Opt Express. 2014 Jun 16;22(12):14792-802. doi: 10.1364/OE.22.014792.
We report on fabrication of a microtoroid resonator of a high-quality factor (i.e., Q-factor of ~3.24 × 10(6) measured under the critical coupling condition) integrated in a microfluidic channel using femtosecond laser three-dimensional (3D) micromachining. Coupling of light into and out of the microresonator has been realized with a fiber taper that is reliably assembled with the microtoroid. The assembly of the fiber to the microtoroid is achieved by welding the fiber taper onto the sidewall of the microtoroid using CO2 laser irradiation. The integrated microresonator maintains a high Q-factor of 3.21 × 10(5) as measured in air, which should still be sufficient for many sensing applications. We test the functionality of the integrated optofluidic sensor by performing bulk refractive index sensing of purified water doped with tiny amount of salt. It is shown that a detection limit of ~1.2 × 10(-4) refractive index unit can be achieved. Our result showcases the capability of integration of high-Q microresonators with complex microfluidic systems using femtosecond laser 3D micromachining.
我们报道了利用飞秒激光三维（3D）微加工技术，在微流控通道中制造出高品质因数（即在临界耦合条件下测得的品质因数约为3.24×10⁶）的微环谐振器。通过与微环可靠组装的光纤锥实现了光与微谐振器的耦合输入和输出。通过使用CO₂激光照射将光纤锥焊接到微环的侧壁上，实现了光纤与微环的组装。集成微谐振器在空气中测量时保持3.21×10⁵的高品质因数，这对于许多传感应用来说应该仍然足够。我们通过对掺杂少量盐的纯净水进行体折射率传感来测试集成光流体传感器的功能。结果表明，折射率单位的检测限约为1.2×10⁻⁴。我们的结果展示了利用飞秒激光3D微加工技术将高Q微谐振器与复杂微流控系统集成的能力。
