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A dual-channel propagation controlled photonic crystal fiber (PCF)-based plasmonic sensor was presented to detect multiple analytes simultaneously. Plasmonic micro-channels were placed on the outer surface of the PCF, which facilitates an easy sensing mechanism. The sensor was numerically investigated by the finite element method (FEM) with the perfectly matched layer (PML) boundary conditions. The proposed sensor performances were analyzed based on optimized sensor parameters, such as confinement loss, resonance coupling, resolution, sensitivity, and figure of merit (FOM). The proposed sensor showed a maximum wavelength sensitivity (WS) of 25,000 nm/refractive index unit (RIU) with a maximum sensor resolution (SR) of 4.0 × 10−6 RIU for channel 2 (Ch-2), and WS of 3000 nm/RIU with SR of 3.33 × 10−5 RIU for channel 1 (Ch-1). To the best of our knowledge, the proposed sensor exhibits the highest WS compared with the previously reported multi-analyte based PCF surface plasmon resonance (SPR) sensors. The proposed sensor could detect the unknown analytes within the refractive index (RI) range of 1.32 to 1.39 in the visible to near infrared region (550 to 1300 nm). In addition, the proposed sensor offers the maximum Figure of Merit (FOM) of 150 and 500 RIU−1 with the limit of detection (LOD) of 1.11 × 10−8 RIU2/nm and 1.6 × 10−10 RIU2/nm for Ch-1 and Ch-2, respectively. Due to its highly sensitive nature, the proposed multi-analyte PCF SPR sensor could be a prominent candidate in the field of biosensing to detect biomolecule interactions and chemical sensing.

A type-II (with broken bandgap) W-shaped nano-heterostructure having layers combination of AlSb, InAs and GaAsSb compound semiconductors has been proposed which can be utilized as high intensity lasing source in MIR (mid infrared region). For this heterostructure, a multiband band k.p Hamiltonian has been simplified to compute the required carrier’s wavefunctions, their subband structures and matrix dipole elements accountable for the probabilistic transitions which results into the high optical gain. For 2-D charge carrier density of 1.5 × 1012 cm−2, the computed results confirm that only the light hole (LH) subbands take part in optical transition in order to produce the high optical gain of the order of ~8850 /cm which corresponds to ~5.2 µm. Keeping in view its high optical gain at ~5.2 µm, the proposed type-II AlSb/InAs/GaAsSb heterostructure can be useful in the environmental monitoring, particularly important for sensing the CO2, CO and NO toxic gases available in the polluted environment. Moreover, this type-II heterostructure can also play an important role in traditional applications such as industrial, medical, MIR spectroscopy, and telecommunications applications which require ~5200 nm wavelength.