Optimization of Single-/Multi-/Single-Mode Intrinsic Fabry–Perot Fiber Sensors

In the present frame of work, optical bistability using a Fabry–Perot (FP) cavity containing 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) dye entrapped in poly-methylmethacrylate (PMMA) matrix is experimentally investigated. Optical nonlinear behavior of solid-state samples is studied using a single-mode Q-switched nanosecond Nd:YAG laser operating at 532 nm. Various optical nonlinear parameters such as nonlinear refractive index (n2) and third-order susceptibility (χ3) of the material are numerically estimated from bistability loops. The origin of optically bistable behavior is attributed to photoisomerization-assisted nonlinear refraction phenomenon. It is observed that nonlinear refraction dominates over nonlinear absorption in giving rise to the optical bistability. The study shows that DCM dye entrapped in solid-state matrices are promising candidate for polymer-based optical switches, data processing, and communication systems.

Download Full-text

Opto-Microfluidic Fabry-Perot Sensor with Extended Air Cavity and Enhanced Pressure Sensitivity

Micromachines ◽

10.3390/mi13010019 ◽

2021 ◽

Vol 13 (1) ◽

pp. 19

Author(s):

Pengfei Zhang ◽

Chao Wang ◽

Liuwei Wan ◽

Qianqian Zhang ◽

Zidan Gong ◽

...

Keyword(s):

Static Pressure ◽

Liquid Surface ◽

Microfluidic Channel ◽

Single Mode ◽

Pressure Sensitivity ◽

Air Cavity ◽

Surface Reflection ◽

Sensor Structure ◽

Fabry Perot ◽

Silica Capillary

An opto-microfluidic static pressure sensor based on a fiber Fabry-Perot Interferometer (FPI) with extended air cavity for enhancing the measuring sensitivity is proposed. The FPI is constructed in a microfluidic channel by the combination of the fixed fiber-end reflection and floating liquid surface reflection faces. A change of the aquatic pressure will cause a drift of the liquid surface and the pressure can be measured by detecting the shift of the FPI spectrum. Sensitivity of the sensor structure can be enhanced significantly by extending the air region of the FPI. The structure is manufactured by using a common single-mode optical fiber, and a silica capillary with the inner wall coated with a hydrophobic film. A sample with 3500 μm air cavity length has demonstrated the pressure sensitivity of about 32.4 μm/kPa, and the temperature cross-sensitivity of about 0.33 kPa/K.

Download Full-text

Large Plasmonic Resonance Shifts From Metal Loss in Slits

10.21203/rs.3.rs-346025/v1 ◽

2021 ◽

Author(s):

Zohreh Sharifi ◽

Reuven Gordon

Keyword(s):

Time Domain ◽

Finite Difference Time Domain ◽

Single Mode ◽

Metal Loss ◽

Plasmonic Resonance ◽

Reflection Phase ◽

Past Experiment ◽

Fabry Perot ◽

The Impact ◽

Difference Time

Abstract The impact of loss on the plasmonic resonances in metal-insulatormetal slits is analyzed, particularly the signiﬁcant effect of loss on the reﬂection phase. The reﬂection is calculated analytically using single mode matching theory with the unconjugated form of the orthogonality relation. This theoretical calculation agrees well with comprehensive simulations, but differs substantially from the conjugated orthogonality result, as was used in past analytical works. This reﬂection phase has a large impact on the plasmonic resonance wavelengths, which are calculated using a Fabry-Pérot theory and compared with past experiment and ﬁnite-difference time-domain simulations.

Download Full-text