Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Lab Chip. 2018 Feb 13;18(4):595-600. doi: 10.1039/c8lc00008e.
Discriminating edible oils from gutter oils has significance in food safety, as illegal gutter oils cannot meet a variety of criteria such as the acid value, peroxide value and quality. To discriminate these illegal cooking oils, we propose an ultrasensitive optofluidic detection method based on a hybrid-waveguide coupler. Prior to the straight waveguide inscription in the cladding of the silica tube using a femtosecond laser, a section of coreless fibre is firstly spliced with the ST to supply a platform for the inscription of an S-band waveguide. Then a pair of microfluidic channels are ablated on the ST using the fs laser to enable liquid analytes to flow in and out of the air channel. In the transmission spectrum, a unique resonant loss dip can be observed, which is produced by coupling the light from the laser inscribed waveguide to the liquid core when the phase-matching condition is met. This hybrid-waveguide coupler with a simplified structure realizes dynamic optofluidic refractive index sensing with an ultrahigh sensitivity of -112 743 nm RIU, a detection limit of 2.08 × 10 RIU and a refractive index detection range from 1.4591 to 1.4622. This novel method can be used for food safety detection, specifically, for the discrimination of gutter oils.
鉴别食用油和地沟油对食品安全具有重要意义，因为非法地沟油无法满足酸值、过氧化物值和质量等多种标准。为了鉴别这些非法食用油，我们提出了一种基于混合波导耦合器的超灵敏光流检测方法。在使用飞秒激光对石英管包层进行直波导刻写之前，首先将无芯光纤与 ST 光纤熔接，为 S 波段波导的刻写提供平台。然后使用飞秒激光在 ST 上烧蚀一对微流道，使液体分析物能够在空气通道内外流动。在传输光谱中，可以观察到一个独特的共振损耗陷波，这是由激光刻写波导中的光与满足相位匹配条件时的液体芯耦合产生的。这种具有简化结构的混合波导耦合器实现了动态光流折射率传感，具有超高灵敏度-112743nm RIU、检测限为 2.08×10 RIU 和折射率检测范围为 1.4591 至 1.4622。这种新方法可用于食品安全检测，特别是用于鉴别地沟油。
