AOMatDev 2022 Abstracts

Area 1 - Advanced Optical Materials and Devices

Nr: 5

Polymer-based Nanoplasmonic Chemical Sensors and Biosensors


Nunzio Cennamo, Francesco Arcadio and Luigi Zeni

Abstract: In this work, nanoplasmonic sensors realized on Poly(methyl methacrylate) (PMMA) chips for bio/chemical applications will be presented. In particular, on a PMMA substrate gold nanograting patterns are produced by exploiting e-beam lithography process to realize highly sensitive plasmonic sensor chips. The main advantage of this sensing approach is based on the capability to consider the PMMA substrate as a transparent substrate (monitoring the nanoplasmonic sensor chip via transmission mode) or to regard it as a slab waveguide (monitoring the nanoplasmonic chip via evanescent field). Therefore, different experimental sensor configurations can be used to change the performances of the nanoplasmonic sensors, obtaining several sensor tools useful for different bio/chemical application fields, such as Point-of-care applications. For instance, when the PMMA substrate is used as a slab waveguide, the nanostrips' orientation forming the grating pattern with respect to the direction of the input light (longitudinal or orthogonal) influences the performances. On the other hand, when the PMMA substrate is used as a transparent substrate, the orientation of the nanograting is not essential. However, both these experimental configurations used to monitor the PMMA-based nanoplasmonic chips present pros and cons. In addition, in nanoplasmonic sensors, in general terms, the use of polymers instead of other materials presents several pros and cons, as will be shown in this work.

Nr: 42

Beam Power and Energy Effects on Dynamics of Creation and Relaxation Photoinduced Birefringence on PAZO Films


Maria Raposo, Ana Monteiro and Paulo A. Ribeiro

Abstract: The influence of writing laser beam power and wavelength in the photoinduced birefringence dynamics on layer-by-layer films of poly(allylamine hydrochloride) (PAH) and poly{1-(4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido)-1,2-ethanediyl, sodium salt} (PAZO) was investigated. Photoinduced birefringence creation/decay dynamics studies, in these PAZO films were characterized in the 5 to 100 mW writing laser power range at the wavelength of 514 nm, showed that the maximum birefringence creation kinetics followed a biexponential behavior, with a slow process and a fast process clearly distinguished, and the fast process accounting for more than 60% of birefringence. The time constants for both fast and slow processes decreased with increasing power of writing beam. The effect of wavelength/energy at fixed writing power on the birefringence creation and relaxation are analyzed in PAZO which have been proven to be stable even at high temperatures. Experimental results show that the increase of laser power turned lead to buildup and relaxation, processes faster, and allows to obtain birefringence values of ~10-4 for different values of applied irradiance. Finally, for a variable wavelength value, the build-up process turned slower whereas the relaxation process stands approximately the same.

Short Papers
Paper Nr: 1

Long Period Grating based Biosensing Technology for the Detection of Vitamin D3


Flavio Esposito, Lucia Sansone, Anubhav Srivastava, Angela M. Cusano, Stefania Campopiano, Michele Giordano and Agostino Iadiccico

Abstract: The label-free detection of vitamin D by employing fiber optic biosensor is reported in this work. Here, the long period grating (LPG) which is inscribed into a specialty fiber i.e., double cladding fiber (DCF) having W-type refractive index profile, is basically employed as a foundation for biosensing. The wet-chemical etching is performed to the outer cladding of the fiber to induce mode transition phenomenon which resulted in an enhanced sensitivity of -1400 nm/RIU towards surrounding medium along with significant visibility (> 15 dB) of grating’s resonance band. The sensing surface of an LPG device is then coated with a graphene oxide (GO) layer of nanometric thickness providing carboxylic functional groups for grafting of 25-OH-D3 specific antibody for vitamin D3. Finally, the detection of vitamin D3 was tested using concentrations in buffer solutions within the clinical range of 1-100 ng/mL resulting a limit of detection (LOD) lower than 1 ng/mL.