# Wave-Shaped Microstructure Cancer Detection Sensor in Terahertz Band: Design and Analysis
## 1 Introduction  
Photonic Crystal Fiber (PCF) has emerged as the most sought-after technology for improving performance and lowering the cost of producing optical fibers because of its huge promise in sensing applications. PCF is incredibly flexible in its design. The core and cladding of this low-loss microstructure fiber are made of a photonic crystal material. It is possible to improve the optical and guiding qualities by changing the size, shape, and placement of air holes. Academics have recently paid a lot of attention to PCF's ability to detect chemical and biological components due to its exceptional features, such as light transmission with low dispersion preservation [1] and confinement loss (CL) with high nonlinearity preservation [2]. The effective area, relative sensitivity, and CL are important guiding characteristics in detection. A lower effective area value provides a larger numerical aperture. PCFs with higher sensitivity and numerical aperture are highly desirable for sensing applications [3, 4]. In Solid Core PCF (SC-PCF), the core is made of robust silicon, while the cladding section is made up of various air rings. The hollow core PCF is arguably the most intriguing type due to its distinct light guide characteristics. The PCF is known as a Hollow-Core PCF if it has a number of small-scaled silicate tubes running along itslongitude that is optically guided by the hollow core in its center (HC-PCF) [5]. As a hollow-core PCF structure was taken into consideration for our design, the HC-PCF contains more analytical volumes than the porous core inside the core region, which improves the contact between light and the materials. A polarization mechanism is also used by the HC-PCF. Both adding stress to the core [6; 7] and producing birefringence due to a strong anisotropy in the hole's structure [8] have been used to demonstrate this. Furthermore, the photonic fiber's background materials (PCF) Topas, Teflon, and Zeonex are used successfully [9; 10; 11; 12]. Cancer is an uncontrolled cell proliferation (often created from one defective cell) [13]. The cancer cells may infect nearby tissues, spread across the body, enter remote areas of the body, and promote the growth of new blood vessels that will feed them. This is due to the loss of the cancer cells' usual growth and spread-controlling systems. Any tissue in the body can give rise to cancerous (malignant) cells. The second leading cause of death today is cancer. The World Health Organization estimates that cancer will be responsible for roughly 10 million deaths in 2020 [14]. Blood cancer, skin cancer, cervical cancer, breast cancer, and adrenal gland cancer are the five basic forms of cancer that typically affect humans. Stages I, II, and III are used to classify malignant cells. In stage I, patients may be cured. Stage II patients may also get treatment; however, stage III patients are always incurable [15]. So, early cancer cell detection is essential for more effective treatment. For the most part, multiple blood tests such as complete blood counts, blood protein analyses, tumor marker analyses, and urine examinations are carried out to detect cancer, but the results are often unable to pinpoint the organ that has been impacted [16]. Taking samples of suspect cells for examination during a biopsy is the only reliable method for determining which cells are malignant [17]. Additional popular diagnostic techniques for finding tumors include positron emission tomography (PET), ultrasound tests, magnetic resonance imaging (MRI), and computed tomography (CT) scans [18; 19; 20]. The lengthy nature of these procedures, which can take anything from two minutes to two or three days, may have negative impacts on cancer patients, for whom a prompt diagnosis is essential. Researchers in opto-electronics are working to create quick cancer cell detectors as a result. RI vary between normal and malignant cells, and as a result, when exposed to the same light source, they will propagate light differently.