Effect of fabrication error on the sensitivity of a one-dimensional photonic crystal sensor for cancer detection

One-dimensional photonic crystal (1D-PC) biosensors are promising for applications like cancer detection due to their high sensitivity, but their performance is often compromised by unavoidable fabrication errors. However, theoretical analyses often do not quantitatively assess the impact of these fabrication errors on key sensor performance parameters, such as sensitivity and peak width. This study addresses this issue by performing a statistical analysis to investigate how random fabrication deviations influence these performance metrics, thereby providing a more realistic evaluation of sensor stability and robustness. For a designed 1D-PC biosensor, the transmission spectrum was first calculated using the transfer matrix method (TMM). A statistical simulation was then performed to analyze how random errors in layer thickness affect the sensor's performance at various error levels (δ) and at two incidence angles, 0° and 85°, with 100 iterations per level. The results showed that as fabrication errors increase, the values for the transmission peak position and Full Width at Half Maximum (FWHM) deviate from their ideal, error-free state. The sensitivity also fluctuates around the ideal value. Interestingly, it was found that some sensor instances could achieve sensitivities higher than the ideal, error-free value. The findings confirm that the 85° incidence angle, previously optimized¹ for high sensitivity, also provides enhanced resistance to fabrication errors compared to normal incidence, making it a robust choice for practical applications and guiding the design of more stable biosensors.