A High Refractive Index Plasmonic Sensor Based on D-Shaped Photonic Crystal Fiber With Laterally Accessible Hollow-Core

Abstract

A unique surface plasmon resonance (SPR) sensor based on photonic crystal fiber (PCF) is proposed in this paper, which consists of a D-shaped profile where a gold film is coated on its flat surface and a laterally accessible hollow core in which the analyte is infiltrated. The spectral sensitivity and the amplitude sensitivity of the proposed sensor are investigated by the finite element method when it is completely and partly immersed into the analyte solution. Simulation results indicate that the proposed sensor can detect the refractive index of the analyte higher than that of the PCF background, and shows higher sensitivity when its core portion is immersed into the analyte. In this way, this sensor can provide the ability of anti-interference from the metal coating. The proposed sensor can be conveniently coated with metal films and provides a possibility for real time sensing, which are not possible with traditional PCF-based SPR sensors.

A Large Detection-Range Plasmonic Sensor Based on An H-Shaped Photonic Crystal Fiber

“…Because the core mode with the electric field predominantly orthogonal to the metal surface can be more readily coupled to the SPP modes on the metal surface [8,9,18,22,[32][33][34], in this design the y-polarized core mode has a better SPR phenomenon than the x-polarized core mode, thus providing a better sensing performance. In what follows, we mainly investigate the sensing performance of the y-polarized core mode.…”

“…By measuring the shift of the peak wavelength, the change in n a can be determined. The sensitivity of the sensor is given by [8,9,12,[14][15][16][17][18][19][20][21][22]24]:…”

“…The laborious process will make the sensor more fragile. In recent years, many researchers have focused on different types of photonic crystal fiber (PCF)-based SPR sensor [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. By introducing air holes in the core area of the PCF, the effective refractive index (n eff ) of the core mode can be reduced, thus easily realizing the phase matching between the core mode and the SPP modes [14][15][16][17][18].…”

“…By introducing air holes in the core area of the PCF, the effective refractive index (n eff ) of the core mode can be reduced, thus easily realizing the phase matching between the core mode and the SPP modes [14][15][16][17][18]. These PCF-based SPR sensors have the advantages of miniaturization, high sensitivity and multi-parameter measurement, which make them more competitive in SPR sensing applications [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. However, currently, PCF-based SPR sensors have two principal challenges: the first problem is the difficult process of the sensor's fabrication, such as metal coating and analyte filling.…”

“…Therefore, it is difficult to coat them with metal film uniformly and to fill them with liquid analyte within the predetermined parameters. Furthermore, these processing methods make it difficult to reuse for the replacement of analyte; Another problem is the narrow refractive index (RI) range of the sensor detection, either employing low RI or high RI PCF-SPR sensors [14][15][16][17][18][19][20][21][22][23]. In these sensors, in order to meet the total reflection condition, the highest RI value detected by the low RI PCF-SPR sensors is lower than that of the fiber materials [14][15][16][17][18][19], whereas the lowest RI value detected by the high RI PCF-SPR sensors must be higher than that of the fiber materials [20][21][22][23].…”