Table 3.

Comprised A Pro and Cons comparative analysis of different techniques.

Method/Technique	Accuracy	Non-Destructive	Suitability for thin eggshells	Speed	Limitations	Simultaneous Measurement of (n, α, ε’, ε’’, σ)?	Cost	Reference
Micrometer Screw (mechanical)	High accuracy (± 1 μm)	No	No	Slow	Requires drilling, and treated as destructive technique	No	Economical	Portugal et al., (2012)5
Ultrasound (Acoustic Method)	Moderate accuracy	Yes	Not suitable for thin shells	Fast	Poor resolution for very thin shells, water coupling also needed and require impedance matching and may not accurately capture the adhesion status between the thin film and substrate;	No	Economical	Voisey & Hamilton, (1976)8
Optical Coherence Tomography (OCT)	High	Yes	Not suitable	Moderate	Limited penetration capability, difficult for fragile shells	No	Expensive	Sabuncu & Akdoğan, (2014)35
X-ray Micro-CT Scanning	Very High (± 0.1 μm)	Yes	Yes suitable for thin shells also	Slow	Expensive, high radiation exposure and hazardous.	No	Expensive	Maurer et al., (2015)1
Magnetic Hall Effect (HETG)	High (± 5 μm)	Yes	Yes suitable for thin shells too	Fast	It requires calibration, not suitable for fragile eggs	No	Economical	Santolo, (2018)10
Cross-section SEM	± 1 μm	No	Yes	Slow	Requires sample coating	No	Expensive	Maurer G (2012)5
Terahertz Time-Domain Spectroscopy (THz-TDS)	High (± 10 μm)	Yes	Yes	Fast	Sensitive to water molecules and need supply of dry air during experiment.expensive	Yes	Expensive	Khaliduzzaman et al. (2020)28